</table>
</sect1>
-
- <sect1 id="views-overview">
- <title>System Views</title>
-
- <para>
- In addition to the system catalogs, <productname>PostgreSQL</productname>
- provides a number of built-in views. Some system views provide convenient
- access to some commonly used queries on the system catalogs. Other views
- provide access to internal server state.
- </para>
-
- <para>
- The information schema (<xref linkend="information-schema"/>) provides
- an alternative set of views which overlap the functionality of the system
- views. Since the information schema is SQL-standard whereas the views
- described here are <productname>PostgreSQL</productname>-specific,
- it's usually better to use the information schema if it provides all
- the information you need.
- </para>
-
- <para>
- <xref linkend="view-table"/> lists the system views described here.
- More detailed documentation of each view follows below.
- There are some additional views that provide access to accumulated
- statistics; they are described in
- <xref linkend="monitoring-stats-views-table"/>.
- </para>
-
- <para>
- Except where noted, all the views described here are read-only.
- </para>
-
- <table id="view-table">
- <title>System Views</title>
-
- <tgroup cols="2">
- <thead>
- <row>
- <entry>View Name</entry>
- <entry>Purpose</entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry><link linkend="view-pg-available-extensions"><structname>pg_available_extensions</structname></link></entry>
- <entry>available extensions</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-available-extension-versions"><structname>pg_available_extension_versions</structname></link></entry>
- <entry>available versions of extensions</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-backend-memory-contexts"><structname>pg_backend_memory_contexts</structname></link></entry>
- <entry>backend memory contexts</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-config"><structname>pg_config</structname></link></entry>
- <entry>compile-time configuration parameters</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-cursors"><structname>pg_cursors</structname></link></entry>
- <entry>open cursors</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-file-settings"><structname>pg_file_settings</structname></link></entry>
- <entry>summary of configuration file contents</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-group"><structname>pg_group</structname></link></entry>
- <entry>groups of database users</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-hba-file-rules"><structname>pg_hba_file_rules</structname></link></entry>
- <entry>summary of client authentication configuration file contents</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-ident-file-mappings"><structname>pg_ident_file_mappings</structname></link></entry>
- <entry>summary of client user name mapping configuration file contents</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-indexes"><structname>pg_indexes</structname></link></entry>
- <entry>indexes</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-locks"><structname>pg_locks</structname></link></entry>
- <entry>locks currently held or awaited</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-matviews"><structname>pg_matviews</structname></link></entry>
- <entry>materialized views</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-policies"><structname>pg_policies</structname></link></entry>
- <entry>policies</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-prepared-statements"><structname>pg_prepared_statements</structname></link></entry>
- <entry>prepared statements</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-prepared-xacts"><structname>pg_prepared_xacts</structname></link></entry>
- <entry>prepared transactions</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-publication-tables"><structname>pg_publication_tables</structname></link></entry>
- <entry>publications and information of their associated tables</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-replication-origin-status"><structname>pg_replication_origin_status</structname></link></entry>
- <entry>information about replication origins, including replication progress</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-replication-slots"><structname>pg_replication_slots</structname></link></entry>
- <entry>replication slot information</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-roles"><structname>pg_roles</structname></link></entry>
- <entry>database roles</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-rules"><structname>pg_rules</structname></link></entry>
- <entry>rules</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-seclabels"><structname>pg_seclabels</structname></link></entry>
- <entry>security labels</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-sequences"><structname>pg_sequences</structname></link></entry>
- <entry>sequences</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-settings"><structname>pg_settings</structname></link></entry>
- <entry>parameter settings</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-shadow"><structname>pg_shadow</structname></link></entry>
- <entry>database users</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-shmem-allocations"><structname>pg_shmem_allocations</structname></link></entry>
- <entry>shared memory allocations</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-stats"><structname>pg_stats</structname></link></entry>
- <entry>planner statistics</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-stats-ext"><structname>pg_stats_ext</structname></link></entry>
- <entry>extended planner statistics</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-stats-ext-exprs"><structname>pg_stats_ext_exprs</structname></link></entry>
- <entry>extended planner statistics for expressions</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-tables"><structname>pg_tables</structname></link></entry>
- <entry>tables</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-timezone-abbrevs"><structname>pg_timezone_abbrevs</structname></link></entry>
- <entry>time zone abbreviations</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-timezone-names"><structname>pg_timezone_names</structname></link></entry>
- <entry>time zone names</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-user"><structname>pg_user</structname></link></entry>
- <entry>database users</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-user-mappings"><structname>pg_user_mappings</structname></link></entry>
- <entry>user mappings</entry>
- </row>
-
- <row>
- <entry><link linkend="view-pg-views"><structname>pg_views</structname></link></entry>
- <entry>views</entry>
- </row>
-
- </tbody>
- </tgroup>
- </table>
- </sect1>
-
- <sect1 id="view-pg-available-extensions">
- <title><structname>pg_available_extensions</structname></title>
-
- <indexterm zone="view-pg-available-extensions">
- <primary>pg_available_extensions</primary>
- </indexterm>
-
- <para>
- The <structname>pg_available_extensions</structname> view lists the
- extensions that are available for installation.
- See also the
- <link linkend="catalog-pg-extension"><structname>pg_extension</structname></link>
- catalog, which shows the extensions currently installed.
- </para>
-
- <table>
- <title><structname>pg_available_extensions</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>name</structfield> <type>name</type>
- </para>
- <para>
- Extension name
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>default_version</structfield> <type>text</type>
- </para>
- <para>
- Name of default version, or <literal>NULL</literal> if none is
- specified
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>installed_version</structfield> <type>text</type>
- </para>
- <para>
- Currently installed version of the extension,
- or <literal>NULL</literal> if not installed
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>comment</structfield> <type>text</type>
- </para>
- <para>
- Comment string from the extension's control file
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- The <structname>pg_available_extensions</structname> view is read-only.
- </para>
- </sect1>
-
- <sect1 id="view-pg-available-extension-versions">
- <title><structname>pg_available_extension_versions</structname></title>
-
- <indexterm zone="view-pg-available-extension-versions">
- <primary>pg_available_extension_versions</primary>
- </indexterm>
-
- <para>
- The <structname>pg_available_extension_versions</structname> view lists the
- specific extension versions that are available for installation.
- See also the <link
- linkend="catalog-pg-extension"><structname>pg_extension</structname></link>
- catalog, which shows the extensions currently installed.
- </para>
-
- <table>
- <title><structname>pg_available_extension_versions</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>name</structfield> <type>name</type>
- </para>
- <para>
- Extension name
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>version</structfield> <type>text</type>
- </para>
- <para>
- Version name
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>installed</structfield> <type>bool</type>
- </para>
- <para>
- True if this version of this extension is currently
- installed
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>superuser</structfield> <type>bool</type>
- </para>
- <para>
- True if only superusers are allowed to install this extension
- (but see <structfield>trusted</structfield>)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>trusted</structfield> <type>bool</type>
- </para>
- <para>
- True if the extension can be installed by non-superusers
- with appropriate privileges
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>relocatable</structfield> <type>bool</type>
- </para>
- <para>
- True if extension can be relocated to another schema
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>schema</structfield> <type>name</type>
- </para>
- <para>
- Name of the schema that the extension must be installed into,
- or <literal>NULL</literal> if partially or fully relocatable
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>requires</structfield> <type>name[]</type>
- </para>
- <para>
- Names of prerequisite extensions,
- or <literal>NULL</literal> if none
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>comment</structfield> <type>text</type>
- </para>
- <para>
- Comment string from the extension's control file
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- The <structname>pg_available_extension_versions</structname> view is
- read-only.
- </para>
- </sect1>
-
- <sect1 id="view-pg-backend-memory-contexts">
- <title><structname>pg_backend_memory_contexts</structname></title>
-
- <indexterm zone="view-pg-backend-memory-contexts">
- <primary>pg_backend_memory_contexts</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_backend_memory_contexts</structname> displays all
- the memory contexts of the server process attached to the current session.
- </para>
- <para>
- <structname>pg_backend_memory_contexts</structname> contains one row
- for each memory context.
- </para>
-
- <table>
- <title><structname>pg_backend_memory_contexts</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>name</structfield> <type>text</type>
- </para>
- <para>
- Name of the memory context
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>ident</structfield> <type>text</type>
- </para>
- <para>
- Identification information of the memory context. This field is truncated at 1024 bytes
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>parent</structfield> <type>text</type>
- </para>
- <para>
- Name of the parent of this memory context
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>level</structfield> <type>int4</type>
- </para>
- <para>
- Distance from TopMemoryContext in context tree
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>total_bytes</structfield> <type>int8</type>
- </para>
- <para>
- Total bytes allocated for this memory context
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>total_nblocks</structfield> <type>int8</type>
- </para>
- <para>
- Total number of blocks allocated for this memory context
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>free_bytes</structfield> <type>int8</type>
- </para>
- <para>
- Free space in bytes
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>free_chunks</structfield> <type>int8</type>
- </para>
- <para>
- Total number of free chunks
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>used_bytes</structfield> <type>int8</type>
- </para>
- <para>
- Used space in bytes
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- By default, the <structname>pg_backend_memory_contexts</structname> view can be
- read only by superusers or roles with the privileges of the
- <literal>pg_read_all_stats</literal> role.
- </para>
- </sect1>
-
- <sect1 id="view-pg-config">
- <title><structname>pg_config</structname></title>
-
- <indexterm zone="view-pg-config">
- <primary>pg_config</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_config</structname> describes the
- compile-time configuration parameters of the currently installed
- version of <productname>PostgreSQL</productname>. It is intended, for example, to
- be used by software packages that want to interface to
- <productname>PostgreSQL</productname> to facilitate finding the required header
- files and libraries. It provides the same basic information as the
- <xref linkend="app-pgconfig"/> <productname>PostgreSQL</productname> client
- application.
- </para>
-
- <para>
- By default, the <structname>pg_config</structname> view can be read
- only by superusers.
- </para>
-
- <table>
- <title><structname>pg_config</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>name</structfield> <type>text</type>
- </para>
- <para>
- The parameter name
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>setting</structfield> <type>text</type>
- </para>
- <para>
- The parameter value
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- </sect1>
-
- <sect1 id="view-pg-cursors">
- <title><structname>pg_cursors</structname></title>
-
- <indexterm zone="view-pg-cursors">
- <primary>pg_cursors</primary>
- </indexterm>
-
- <para>
- The <structname>pg_cursors</structname> view lists the cursors that
- are currently available. Cursors can be defined in several ways:
- <itemizedlist>
- <listitem>
- <para>
- via the <link linkend="sql-declare"><command>DECLARE</command></link>
- statement in SQL
- </para>
- </listitem>
-
- <listitem>
- <para>
- via the Bind message in the frontend/backend protocol, as
- described in <xref linkend="protocol-flow-ext-query"/>
- </para>
- </listitem>
-
- <listitem>
- <para>
- via the Server Programming Interface (SPI), as described in
- <xref linkend="spi-interface"/>
- </para>
- </listitem>
- </itemizedlist>
-
- The <structname>pg_cursors</structname> view displays cursors
- created by any of these means. Cursors only exist for the duration
- of the transaction that defines them, unless they have been
- declared <literal>WITH HOLD</literal>. Therefore non-holdable
- cursors are only present in the view until the end of their
- creating transaction.
-
- <note>
- <para>
- Cursors are used internally to implement some of the components
- of <productname>PostgreSQL</productname>, such as procedural languages.
- Therefore, the <structname>pg_cursors</structname> view might include cursors
- that have not been explicitly created by the user.
- </para>
- </note>
- </para>
-
- <table>
- <title><structname>pg_cursors</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>name</structfield> <type>text</type>
- </para>
- <para>
- The name of the cursor
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>statement</structfield> <type>text</type>
- </para>
- <para>
- The verbatim query string submitted to declare this cursor
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>is_holdable</structfield> <type>bool</type>
- </para>
- <para>
- <literal>true</literal> if the cursor is holdable (that is, it
- can be accessed after the transaction that declared the cursor
- has committed); <literal>false</literal> otherwise
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>is_binary</structfield> <type>bool</type>
- </para>
- <para>
- <literal>true</literal> if the cursor was declared
- <literal>BINARY</literal>; <literal>false</literal>
- otherwise
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>is_scrollable</structfield> <type>bool</type>
- </para>
- <para>
- <literal>true</literal> if the cursor is scrollable (that is, it
- allows rows to be retrieved in a nonsequential manner);
- <literal>false</literal> otherwise
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>creation_time</structfield> <type>timestamptz</type>
- </para>
- <para>
- The time at which the cursor was declared
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- The <structname>pg_cursors</structname> view is read-only.
- </para>
-
- </sect1>
-
- <sect1 id="view-pg-file-settings">
- <title><structname>pg_file_settings</structname></title>
-
- <indexterm zone="view-pg-file-settings">
- <primary>pg_file_settings</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_file_settings</structname> provides a summary of
- the contents of the server's configuration file(s). A row appears in
- this view for each <quote>name = value</quote> entry appearing in the files,
- with annotations indicating whether the value could be applied
- successfully. Additional row(s) may appear for problems not linked to
- a <quote>name = value</quote> entry, such as syntax errors in the files.
- </para>
-
- <para>
- This view is helpful for checking whether planned changes in the
- configuration files will work, or for diagnosing a previous failure.
- Note that this view reports on the <emphasis>current</emphasis> contents of the
- files, not on what was last applied by the server. (The
- <link linkend="view-pg-settings"><structname>pg_settings</structname></link>
- view is usually sufficient to determine that.)
- </para>
-
- <para>
- By default, the <structname>pg_file_settings</structname> view can be read
- only by superusers.
- </para>
-
- <table>
- <title><structname>pg_file_settings</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>sourcefile</structfield> <type>text</type>
- </para>
- <para>
- Full path name of the configuration file
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>sourceline</structfield> <type>int4</type>
- </para>
- <para>
- Line number within the configuration file where the entry appears
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>seqno</structfield> <type>int4</type>
- </para>
- <para>
- Order in which the entries are processed (1..<replaceable>n</replaceable>)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>name</structfield> <type>text</type>
- </para>
- <para>
- Configuration parameter name
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>setting</structfield> <type>text</type>
- </para>
- <para>
- Value to be assigned to the parameter
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>applied</structfield> <type>bool</type>
- </para>
- <para>
- True if the value can be applied successfully
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>error</structfield> <type>text</type>
- </para>
- <para>
- If not null, an error message indicating why this entry could
- not be applied
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- If the configuration file contains syntax errors or invalid parameter
- names, the server will not attempt to apply any settings from it, and
- therefore all the <structfield>applied</structfield> fields will read as false.
- In such a case there will be one or more rows with
- non-null <structfield>error</structfield> fields indicating the
- problem(s). Otherwise, individual settings will be applied if possible.
- If an individual setting cannot be applied (e.g., invalid value, or the
- setting cannot be changed after server start) it will have an appropriate
- message in the <structfield>error</structfield> field. Another way that
- an entry might have <structfield>applied</structfield> = false is that it is
- overridden by a later entry for the same parameter name; this case is not
- considered an error so nothing appears in
- the <structfield>error</structfield> field.
- </para>
-
- <para>
- See <xref linkend="config-setting"/> for more information about the various
- ways to change run-time parameters.
- </para>
-
-</sect1>
-
- <sect1 id="view-pg-group">
- <title><structname>pg_group</structname></title>
-
- <indexterm zone="view-pg-group">
- <primary>pg_group</primary>
- </indexterm>
-
- <!-- Unlike information_schema.applicable_roles, this shows no members for
- pg_database_owner. The v8.1 catalog would have shown no members if
- that role had existed at the time. -->
- <para>
- The view <structname>pg_group</structname> exists for backwards
- compatibility: it emulates a catalog that existed in
- <productname>PostgreSQL</productname> before version 8.1.
- It shows the names and members of all roles that are marked as not
- <structfield>rolcanlogin</structfield>, which is an approximation to the set
- of roles that are being used as groups.
- </para>
-
- <table>
- <title><structname>pg_group</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>groname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
- </para>
- <para>
- Name of the group
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>grosysid</structfield> <type>oid</type>
- (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>oid</structfield>)
- </para>
- <para>
- ID of this group
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>grolist</structfield> <type>oid[]</type>
- (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>oid</structfield>)
- </para>
- <para>
- An array containing the IDs of the roles in this group
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- </sect1>
-
- <sect1 id="view-pg-hba-file-rules">
- <title><structname>pg_hba_file_rules</structname></title>
-
- <indexterm zone="view-pg-hba-file-rules">
- <primary>pg_hba_file_rules</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_hba_file_rules</structname> provides a summary of
- the contents of the client authentication configuration file,
- <link linkend="auth-pg-hba-conf"><filename>pg_hba.conf</filename></link>.
- A row appears in this view for each
- non-empty, non-comment line in the file, with annotations indicating
- whether the rule could be applied successfully.
- </para>
-
- <para>
- This view can be helpful for checking whether planned changes in the
- authentication configuration file will work, or for diagnosing a previous
- failure. Note that this view reports on the <emphasis>current</emphasis> contents
- of the file, not on what was last loaded by the server.
- </para>
-
- <para>
- By default, the <structname>pg_hba_file_rules</structname> view can be read
- only by superusers.
- </para>
-
- <table>
- <title><structname>pg_hba_file_rules</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>line_number</structfield> <type>int4</type>
- </para>
- <para>
- Line number of this rule in <filename>pg_hba.conf</filename>
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>type</structfield> <type>text</type>
- </para>
- <para>
- Type of connection
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>database</structfield> <type>text[]</type>
- </para>
- <para>
- List of database name(s) to which this rule applies
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>user_name</structfield> <type>text[]</type>
- </para>
- <para>
- List of user and group name(s) to which this rule applies
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>address</structfield> <type>text</type>
- </para>
- <para>
- Host name or IP address, or one
- of <literal>all</literal>, <literal>samehost</literal>,
- or <literal>samenet</literal>, or null for local connections
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>netmask</structfield> <type>text</type>
- </para>
- <para>
- IP address mask, or null if not applicable
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>auth_method</structfield> <type>text</type>
- </para>
- <para>
- Authentication method
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>options</structfield> <type>text[]</type>
- </para>
- <para>
- Options specified for authentication method, if any
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>error</structfield> <type>text</type>
- </para>
- <para>
- If not null, an error message indicating why this
- line could not be processed
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- Usually, a row reflecting an incorrect entry will have values for only
- the <structfield>line_number</structfield> and <structfield>error</structfield> fields.
- </para>
-
- <para>
- See <xref linkend="client-authentication"/> for more information about
- client authentication configuration.
- </para>
- </sect1>
-
- <sect1 id="view-pg-ident-file-mappings">
- <title><structname>pg_ident_file_mappings</structname></title>
-
- <indexterm zone="view-pg-ident-file-mappings">
- <primary>pg_ident_file_mappings</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_ident_file_mappings</structname> provides a summary
- of the contents of the client user name mapping configuration file,
- <link linkend="auth-username-maps"><filename>pg_ident.conf</filename></link>.
- A row appears in this view for each non-empty, non-comment line in the file,
- with annotations indicating whether the rule could be applied successfully.
- </para>
-
- <para>
- This view can be helpful for checking whether planned changes in the
- authentication configuration file will work, or for diagnosing a previous
- failure. Note that this view reports on the <emphasis>current</emphasis>
- contents of the file, not on what was last loaded by the server.
- </para>
-
- <para>
- By default, the <structname>pg_ident_file_mappings</structname> view can be
- read only by superusers.
- </para>
-
- <table>
- <title><structname>pg_ident_file_mappings</structname> Columns</title> <tgroup
- cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>line_number</structfield> <type>int4</type>
- </para>
- <para>
- Line number of this rule in <filename>pg_ident.conf</filename>
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>map_name</structfield> <type>text</type>
- </para>
- <para>
- Name of the map
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>sys_name</structfield> <type>text</type>
- </para>
- <para>
- Detected user name of the client
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>pg_username</structfield> <type>text</type>
- </para>
- <para>
- Requested PostgreSQL user name
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>error</structfield> <type>text</type>
- </para>
- <para>
- If not <literal>NULL</literal>, an error message indicating why this
- line could not be processed
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- Usually, a row reflecting an incorrect entry will have values for only
- the <structfield>line_number</structfield> and <structfield>error</structfield> fields.
- </para>
-
- <para>
- See <xref linkend="client-authentication"/> for more information about
- client authentication configuration.
- </para>
- </sect1>
-
- <sect1 id="view-pg-indexes">
- <title><structname>pg_indexes</structname></title>
-
- <indexterm zone="view-pg-indexes">
- <primary>pg_indexes</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_indexes</structname> provides access to
- useful information about each index in the database.
- </para>
-
- <table>
- <title><structname>pg_indexes</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>schemaname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
- </para>
- <para>
- Name of schema containing table and index
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>tablename</structfield> <type>name</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
- </para>
- <para>
- Name of table the index is for
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>indexname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
- </para>
- <para>
- Name of index
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>tablespace</structfield> <type>name</type>
- (references <link linkend="catalog-pg-tablespace"><structname>pg_tablespace</structname></link>.<structfield>spcname</structfield>)
- </para>
- <para>
- Name of tablespace containing index (null if default for database)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>indexdef</structfield> <type>text</type>
- </para>
- <para>
- Index definition (a reconstructed <xref linkend="sql-createindex"/>
- command)
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- </sect1>
-
- <sect1 id="view-pg-locks">
- <title><structname>pg_locks</structname></title>
-
- <indexterm zone="view-pg-locks">
- <primary>pg_locks</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_locks</structname> provides access to
- information about the locks held by active processes within the
- database server. See <xref linkend="mvcc"/> for more discussion
- of locking.
- </para>
-
- <para>
- <structname>pg_locks</structname> contains one row per active lockable
- object, requested lock mode, and relevant process. Thus, the same
- lockable object might
- appear many times, if multiple processes are holding or waiting
- for locks on it. However, an object that currently has no locks on it
- will not appear at all.
- </para>
-
- <para>
- There are several distinct types of lockable objects:
- whole relations (e.g., tables), individual pages of relations,
- individual tuples of relations,
- transaction IDs (both virtual and permanent IDs),
- and general database objects (identified by class OID and object OID,
- in the same way as in <link linkend="catalog-pg-description"><structname>pg_description</structname></link> or
- <link linkend="catalog-pg-depend"><structname>pg_depend</structname></link>). Also, the right to extend a
- relation is represented as a separate lockable object, as is the right to
- update <structname>pg_database</structname>.<structfield>datfrozenxid</structfield>.
- Also, <quote>advisory</quote> locks can be taken on numbers that have
- user-defined meanings.
- </para>
-
- <table>
- <title><structname>pg_locks</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>locktype</structfield> <type>text</type>
- </para>
- <para>
- Type of the lockable object:
- <literal>relation</literal>,
- <literal>extend</literal>,
- <literal>frozenid</literal>,
- <literal>page</literal>,
- <literal>tuple</literal>,
- <literal>transactionid</literal>,
- <literal>virtualxid</literal>,
- <literal>spectoken</literal>,
- <literal>object</literal>,
- <literal>userlock</literal>, or
- <literal>advisory</literal>.
- (See also <xref linkend="wait-event-lock-table"/>.)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>database</structfield> <type>oid</type>
- (references <link linkend="catalog-pg-database"><structname>pg_database</structname></link>.<structfield>oid</structfield>)
- </para>
- <para>
- OID of the database in which the lock target exists, or
- zero if the target is a shared object, or
- null if the target is a transaction ID
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>relation</structfield> <type>oid</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield>)
- </para>
- <para>
- OID of the relation targeted by the lock, or null if the target is not
- a relation or part of a relation
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>page</structfield> <type>int4</type>
- </para>
- <para>
- Page number targeted by the lock within the relation,
- or null if the target is not a relation page or tuple
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>tuple</structfield> <type>int2</type>
- </para>
- <para>
- Tuple number targeted by the lock within the page,
- or null if the target is not a tuple
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>virtualxid</structfield> <type>text</type>
- </para>
- <para>
- Virtual ID of the transaction targeted by the lock,
- or null if the target is not a virtual transaction ID
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>transactionid</structfield> <type>xid</type>
- </para>
- <para>
- ID of the transaction targeted by the lock,
- or null if the target is not a transaction ID
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>classid</structfield> <type>oid</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield>)
- </para>
- <para>
- OID of the system catalog containing the lock target, or null if the
- target is not a general database object
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>objid</structfield> <type>oid</type>
- (references any OID column)
- </para>
- <para>
- OID of the lock target within its system catalog, or null if the
- target is not a general database object
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>objsubid</structfield> <type>int2</type>
- </para>
- <para>
- Column number targeted by the lock (the
- <structfield>classid</structfield> and <structfield>objid</structfield> refer to the
- table itself),
- or zero if the target is some other general database object,
- or null if the target is not a general database object
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>virtualtransaction</structfield> <type>text</type>
- </para>
- <para>
- Virtual ID of the transaction that is holding or awaiting this lock
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>pid</structfield> <type>int4</type>
- </para>
- <para>
- Process ID of the server process holding or awaiting this
- lock, or null if the lock is held by a prepared transaction
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>mode</structfield> <type>text</type>
- </para>
- <para>
- Name of the lock mode held or desired by this process (see <xref linkend="locking-tables"/> and <xref linkend="xact-serializable"/>)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>granted</structfield> <type>bool</type>
- </para>
- <para>
- True if lock is held, false if lock is awaited
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>fastpath</structfield> <type>bool</type>
- </para>
- <para>
- True if lock was taken via fast path, false if taken via main
- lock table
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>waitstart</structfield> <type>timestamptz</type>
- </para>
- <para>
- Time when the server process started waiting for this lock,
- or null if the lock is held.
- Note that this can be null for a very short period of time after
- the wait started even though <structfield>granted</structfield>
- is <literal>false</literal>.
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- <structfield>granted</structfield> is true in a row representing a lock
- held by the indicated process. False indicates that this process is
- currently waiting to acquire this lock, which implies that at least one
- other process is holding or waiting for a conflicting lock mode on the same
- lockable object. The waiting process will sleep until the other lock is
- released (or a deadlock situation is detected). A single process can be
- waiting to acquire at most one lock at a time.
- </para>
-
- <para>
- Throughout running a transaction, a server process holds an exclusive lock
- on the transaction's virtual transaction ID. If a permanent ID is assigned
- to the transaction (which normally happens only if the transaction changes
- the state of the database), it also holds an exclusive lock on the
- transaction's permanent transaction ID until it ends. When a process finds
- it necessary to wait specifically for another transaction to end, it does
- so by attempting to acquire share lock on the other transaction's ID
- (either virtual or permanent ID depending on the situation). That will
- succeed only when the other transaction terminates and releases its locks.
- </para>
-
- <para>
- Although tuples are a lockable type of object,
- information about row-level locks is stored on disk, not in memory,
- and therefore row-level locks normally do not appear in this view.
- If a process is waiting for a
- row-level lock, it will usually appear in the view as waiting for the
- permanent transaction ID of the current holder of that row lock.
- </para>
-
- <para>
- Advisory locks can be acquired on keys consisting of either a single
- <type>bigint</type> value or two integer values.
- A <type>bigint</type> key is displayed with its
- high-order half in the <structfield>classid</structfield> column, its low-order half
- in the <structfield>objid</structfield> column, and <structfield>objsubid</structfield> equal
- to 1. The original <type>bigint</type> value can be reassembled with the
- expression <literal>(classid::bigint << 32) |
- objid::bigint</literal>. Integer keys are displayed with the
- first key in the
- <structfield>classid</structfield> column, the second key in the <structfield>objid</structfield>
- column, and <structfield>objsubid</structfield> equal to 2. The actual meaning of
- the keys is up to the user. Advisory locks are local to each database,
- so the <structfield>database</structfield> column is meaningful for an advisory lock.
- </para>
-
- <para>
- <structname>pg_locks</structname> provides a global view of all locks
- in the database cluster, not only those relevant to the current database.
- Although its <structfield>relation</structfield> column can be joined
- against <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield> to identify locked
- relations, this will only work correctly for relations in the current
- database (those for which the <structfield>database</structfield> column
- is either the current database's OID or zero).
- </para>
-
- <para>
- The <structfield>pid</structfield> column can be joined to the
- <structfield>pid</structfield> column of the
- <link linkend="monitoring-pg-stat-activity-view">
- <structname>pg_stat_activity</structname></link>
- view to get more
- information on the session holding or awaiting each lock,
- for example
-<programlisting>
-SELECT * FROM pg_locks pl LEFT JOIN pg_stat_activity psa
- ON pl.pid = psa.pid;
-</programlisting>
- Also, if you are using prepared transactions, the
- <structfield>virtualtransaction</structfield> column can be joined to the
- <structfield>transaction</structfield> column of the <link
- linkend="view-pg-prepared-xacts"><structname>pg_prepared_xacts</structname></link>
- view to get more information on prepared transactions that hold locks.
- (A prepared transaction can never be waiting for a lock,
- but it continues to hold the locks it acquired while running.)
- For example:
-<programlisting>
-SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
- ON pl.virtualtransaction = '-1/' || ppx.transaction;
-</programlisting>
- </para>
-
- <para>
- While it is possible to obtain information about which processes block
- which other processes by joining <structname>pg_locks</structname> against
- itself, this is very difficult to get right in detail. Such a query would
- have to encode knowledge about which lock modes conflict with which
- others. Worse, the <structname>pg_locks</structname> view does not expose
- information about which processes are ahead of which others in lock wait
- queues, nor information about which processes are parallel workers running
- on behalf of which other client sessions. It is better to use
- the <function>pg_blocking_pids()</function> function
- (see <xref linkend="functions-info-session-table"/>) to identify which
- process(es) a waiting process is blocked behind.
- </para>
-
- <para>
- The <structname>pg_locks</structname> view displays data from both the
- regular lock manager and the predicate lock manager, which are
- separate systems; in addition, the regular lock manager subdivides its
- locks into regular and <firstterm>fast-path</firstterm> locks.
- This data is not guaranteed to be entirely consistent.
- When the view is queried,
- data on fast-path locks (with <structfield>fastpath</structfield> = <literal>true</literal>)
- is gathered from each backend one at a time, without freezing the state of
- the entire lock manager, so it is possible for locks to be taken or
- released while information is gathered. Note, however, that these locks are
- known not to conflict with any other lock currently in place. After
- all backends have been queried for fast-path locks, the remainder of the
- regular lock manager is locked as a unit, and a consistent snapshot of all
- remaining locks is collected as an atomic action. After unlocking the
- regular lock manager, the predicate lock manager is similarly locked and all
- predicate locks are collected as an atomic action. Thus, with the exception
- of fast-path locks, each lock manager will deliver a consistent set of
- results, but as we do not lock both lock managers simultaneously, it is
- possible for locks to be taken or released after we interrogate the regular
- lock manager and before we interrogate the predicate lock manager.
- </para>
-
- <para>
- Locking the regular and/or predicate lock manager could have some
- impact on database performance if this view is very frequently accessed.
- The locks are held only for the minimum amount of time necessary to
- obtain data from the lock managers, but this does not completely eliminate
- the possibility of a performance impact.
- </para>
-
- </sect1>
-
- <sect1 id="view-pg-matviews">
- <title><structname>pg_matviews</structname></title>
-
- <indexterm zone="view-pg-matviews">
- <primary>pg_matviews</primary>
- </indexterm>
-
- <indexterm zone="view-pg-matviews">
- <primary>materialized views</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_matviews</structname> provides access to
- useful information about each materialized view in the database.
- </para>
-
- <table>
- <title><structname>pg_matviews</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>schemaname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
- </para>
- <para>
- Name of schema containing materialized view
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>matviewname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
- </para>
- <para>
- Name of materialized view
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>matviewowner</structfield> <type>name</type>
- (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
- </para>
- <para>
- Name of materialized view's owner
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>tablespace</structfield> <type>name</type>
- (references <link linkend="catalog-pg-tablespace"><structname>pg_tablespace</structname></link>.<structfield>spcname</structfield>)
- </para>
- <para>
- Name of tablespace containing materialized view (null if default for database)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>hasindexes</structfield> <type>bool</type>
- </para>
- <para>
- True if materialized view has (or recently had) any indexes
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>ispopulated</structfield> <type>bool</type>
- </para>
- <para>
- True if materialized view is currently populated
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>definition</structfield> <type>text</type>
- </para>
- <para>
- Materialized view definition (a reconstructed <xref linkend="sql-select"/> query)
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- </sect1>
-
- <sect1 id="view-pg-policies">
- <title><structname>pg_policies</structname></title>
-
- <indexterm zone="view-pg-policies">
- <primary>pg_policies</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_policies</structname> provides access to
- useful information about each row-level security policy in the database.
- </para>
-
- <table>
- <title><structname>pg_policies</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>schemaname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
- </para>
- <para>
- Name of schema containing table policy is on
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>tablename</structfield> <type>name</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
- </para>
- <para>
- Name of table policy is on
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>policyname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-policy"><structname>pg_policy</structname></link>.<structfield>polname</structfield>)
- </para>
- <para>
- Name of policy
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>permissive</structfield> <type>text</type>
- </para>
- <para>
- Is the policy permissive or restrictive?
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>roles</structfield> <type>name[]</type>
- </para>
- <para>
- The roles to which this policy applies
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>cmd</structfield> <type>text</type>
- </para>
- <para>
- The command type to which the policy is applied
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>qual</structfield> <type>text</type>
- </para>
- <para>
- The expression added to the security barrier qualifications for
- queries that this policy applies to
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>with_check</structfield> <type>text</type>
- </para>
- <para>
- The expression added to the WITH CHECK qualifications for
- queries that attempt to add rows to this table
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- </sect1>
-
- <sect1 id="view-pg-prepared-statements">
- <title><structname>pg_prepared_statements</structname></title>
-
- <indexterm zone="view-pg-prepared-statements">
- <primary>pg_prepared_statements</primary>
- </indexterm>
-
- <para>
- The <structname>pg_prepared_statements</structname> view displays
- all the prepared statements that are available in the current
- session. See <xref linkend="sql-prepare"/> for more information about prepared
- statements.
- </para>
-
- <para>
- <structname>pg_prepared_statements</structname> contains one row
- for each prepared statement. Rows are added to the view when a new
- prepared statement is created and removed when a prepared statement
- is released (for example, via the <link linkend="sql-deallocate"><command>DEALLOCATE</command></link> command).
- </para>
-
- <table>
- <title><structname>pg_prepared_statements</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>name</structfield> <type>text</type>
- </para>
- <para>
- The identifier of the prepared statement
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>statement</structfield> <type>text</type>
- </para>
- <para>
- The query string submitted by the client to create this
- prepared statement. For prepared statements created via SQL,
- this is the <command>PREPARE</command> statement submitted by
- the client. For prepared statements created via the
- frontend/backend protocol, this is the text of the prepared
- statement itself.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>prepare_time</structfield> <type>timestamptz</type>
- </para>
- <para>
- The time at which the prepared statement was created
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>parameter_types</structfield> <type>regtype[]</type>
- </para>
- <para>
- The expected parameter types for the prepared statement in the
- form of an array of <type>regtype</type>. The OID corresponding
- to an element of this array can be obtained by casting the
- <type>regtype</type> value to <type>oid</type>.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>result_types</structfield> <type>regtype[]</type>
- </para>
- <para>
- The types of the columns returned by the prepared statement in the
- form of an array of <type>regtype</type>. The OID corresponding
- to an element of this array can be obtained by casting the
- <type>regtype</type> value to <type>oid</type>.
- If the prepared statement does not provide a result (e.g., a DML
- statement), then this field will be null.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>from_sql</structfield> <type>bool</type>
- </para>
- <para>
- <literal>true</literal> if the prepared statement was created
- via the <command>PREPARE</command> SQL command;
- <literal>false</literal> if the statement was prepared via the
- frontend/backend protocol
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>generic_plans</structfield> <type>int8</type>
- </para>
- <para>
- Number of times generic plan was chosen
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>custom_plans</structfield> <type>int8</type>
- </para>
- <para>
- Number of times custom plan was chosen
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- The <structname>pg_prepared_statements</structname> view is read-only.
- </para>
- </sect1>
-
- <sect1 id="view-pg-prepared-xacts">
- <title><structname>pg_prepared_xacts</structname></title>
-
- <indexterm zone="view-pg-prepared-xacts">
- <primary>pg_prepared_xacts</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_prepared_xacts</structname> displays
- information about transactions that are currently prepared for two-phase
- commit (see <xref linkend="sql-prepare-transaction"/> for details).
- </para>
-
- <para>
- <structname>pg_prepared_xacts</structname> contains one row per prepared
- transaction. An entry is removed when the transaction is committed or
- rolled back.
- </para>
-
- <table>
- <title><structname>pg_prepared_xacts</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>transaction</structfield> <type>xid</type>
- </para>
- <para>
- Numeric transaction identifier of the prepared transaction
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>gid</structfield> <type>text</type>
- </para>
- <para>
- Global transaction identifier that was assigned to the transaction
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>prepared</structfield> <type>timestamptz</type>
- </para>
- <para>
- Time at which the transaction was prepared for commit
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>owner</structfield> <type>name</type>
- (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
- </para>
- <para>
- Name of the user that executed the transaction
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>database</structfield> <type>name</type>
- (references <link linkend="catalog-pg-database"><structname>pg_database</structname></link>.<structfield>datname</structfield>)
- </para>
- <para>
- Name of the database in which the transaction was executed
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- When the <structname>pg_prepared_xacts</structname> view is accessed, the
- internal transaction manager data structures are momentarily locked, and
- a copy is made for the view to display. This ensures that the
- view produces a consistent set of results, while not blocking
- normal operations longer than necessary. Nonetheless
- there could be some impact on database performance if this view is
- frequently accessed.
- </para>
-
- </sect1>
-
- <sect1 id="view-pg-publication-tables">
- <title><structname>pg_publication_tables</structname></title>
-
- <indexterm zone="view-pg-publication-tables">
- <primary>pg_publication_tables</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_publication_tables</structname> provides
- information about the mapping between publications and information of
- tables they contain. Unlike the underlying catalog
- <link linkend="catalog-pg-publication-rel"><structname>pg_publication_rel</structname></link>,
- this view expands publications defined as <literal>FOR ALL TABLES</literal>
- and <literal>FOR ALL TABLES IN SCHEMA</literal>, so for such publications
- there will be a row for each eligible table.
- </para>
-
- <table>
- <title><structname>pg_publication_tables</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>pubname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-publication"><structname>pg_publication</structname></link>.<structfield>pubname</structfield>)
- </para>
- <para>
- Name of publication
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>schemaname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
- </para>
- <para>
- Name of schema containing table
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>tablename</structfield> <type>name</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
- </para>
- <para>
- Name of table
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>attnames</structfield> <type>name[]</type>
- (references <link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>.<structfield>attname</structfield>)
- </para>
- <para>
- Names of table columns included in the publication. This contains all
- the columns of the table when the user didn't specify the column list
- for the table.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>rowfilter</structfield> <type>text</type>
- </para>
- <para>
- Expression for the table's publication qualifying condition
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
- </sect1>
-
- <sect1 id="view-pg-replication-origin-status">
- <title><structname>pg_replication_origin_status</structname></title>
-
- <indexterm zone="view-pg-replication-origin-status">
- <primary>pg_replication_origin_status</primary>
- </indexterm>
-
- <para>
- The <structname>pg_replication_origin_status</structname> view
- contains information about how far replay for a certain origin has
- progressed. For more on replication origins
- see <xref linkend="replication-origins"/>.
- </para>
-
- <table>
- <title><structname>pg_replication_origin_status</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>local_id</structfield> <type>oid</type>
- (references <link linkend="catalog-pg-replication-origin"><structname>pg_replication_origin</structname></link>.<structfield>roident</structfield>)
- </para>
- <para>
- internal node identifier
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>external_id</structfield> <type>text</type>
- (references <link linkend="catalog-pg-replication-origin"><structname>pg_replication_origin</structname></link>.<structfield>roname</structfield>)
- </para>
- <para>
- external node identifier
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>remote_lsn</structfield> <type>pg_lsn</type>
- </para>
- <para>
- The origin node's LSN up to which data has been replicated.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>local_lsn</structfield> <type>pg_lsn</type>
- </para>
- <para>
- This node's LSN at which <literal>remote_lsn</literal> has
- been replicated. Used to flush commit records before persisting
- data to disk when using asynchronous commits.
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
- </sect1>
-
- <sect1 id="view-pg-replication-slots">
- <title><structname>pg_replication_slots</structname></title>
-
- <indexterm zone="view-pg-replication-slots">
- <primary>pg_replication_slots</primary>
- </indexterm>
-
- <para>
- The <structname>pg_replication_slots</structname> view provides a listing
- of all replication slots that currently exist on the database cluster,
- along with their current state.
- </para>
-
- <para>
- For more on replication slots,
- see <xref linkend="streaming-replication-slots"/> and <xref linkend="logicaldecoding"/>.
- </para>
-
- <table>
- <title><structname>pg_replication_slots</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>slot_name</structfield> <type>name</type>
- </para>
- <para>
- A unique, cluster-wide identifier for the replication slot
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>plugin</structfield> <type>name</type>
- </para>
- <para>
- The base name of the shared object containing the output plugin this logical slot is using, or null for physical slots.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>slot_type</structfield> <type>text</type>
- </para>
- <para>
- The slot type: <literal>physical</literal> or <literal>logical</literal>
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>datoid</structfield> <type>oid</type>
- (references <link linkend="catalog-pg-database"><structname>pg_database</structname></link>.<structfield>oid</structfield>)
- </para>
- <para>
- The OID of the database this slot is associated with, or
- null. Only logical slots have an associated database.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>database</structfield> <type>name</type>
- (references <link linkend="catalog-pg-database"><structname>pg_database</structname></link>.<structfield>datname</structfield>)
- </para>
- <para>
- The name of the database this slot is associated with, or
- null. Only logical slots have an associated database.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>temporary</structfield> <type>bool</type>
- </para>
- <para>
- True if this is a temporary replication slot. Temporary slots are
- not saved to disk and are automatically dropped on error or when
- the session has finished.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>active</structfield> <type>bool</type>
- </para>
- <para>
- True if this slot is currently actively being used
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>active_pid</structfield> <type>int4</type>
- </para>
- <para>
- The process ID of the session using this slot if the slot
- is currently actively being used. <literal>NULL</literal> if
- inactive.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>xmin</structfield> <type>xid</type>
- </para>
- <para>
- The oldest transaction that this slot needs the database to
- retain. <literal>VACUUM</literal> cannot remove tuples deleted
- by any later transaction.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>catalog_xmin</structfield> <type>xid</type>
- </para>
- <para>
- The oldest transaction affecting the system catalogs that this
- slot needs the database to retain. <literal>VACUUM</literal> cannot
- remove catalog tuples deleted by any later transaction.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>restart_lsn</structfield> <type>pg_lsn</type>
- </para>
- <para>
- The address (<literal>LSN</literal>) of oldest WAL which still
- might be required by the consumer of this slot and thus won't be
- automatically removed during checkpoints unless this LSN
- gets behind more than <xref linkend="guc-max-slot-wal-keep-size"/>
- from the current LSN. <literal>NULL</literal>
- if the <literal>LSN</literal> of this slot has never been reserved.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>confirmed_flush_lsn</structfield> <type>pg_lsn</type>
- </para>
- <para>
- The address (<literal>LSN</literal>) up to which the logical
- slot's consumer has confirmed receiving data. Data older than this is
- not available anymore. <literal>NULL</literal> for physical slots.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>wal_status</structfield> <type>text</type>
- </para>
- <para>
- Availability of WAL files claimed by this slot.
- Possible values are:
- <itemizedlist>
- <listitem>
- <para><literal>reserved</literal> means that the claimed files
- are within <varname>max_wal_size</varname>.</para>
- </listitem>
- <listitem>
- <para><literal>extended</literal> means
- that <varname>max_wal_size</varname> is exceeded but the files are
- still retained, either by the replication slot or
- by <varname>wal_keep_size</varname>.
- </para>
- </listitem>
- <listitem>
- <para>
- <literal>unreserved</literal> means that the slot no longer
- retains the required WAL files and some of them are to be removed at
- the next checkpoint. This state can return
- to <literal>reserved</literal> or <literal>extended</literal>.
- </para>
- </listitem>
- <listitem>
- <para>
- <literal>lost</literal> means that some required WAL files have
- been removed and this slot is no longer usable.
- </para>
- </listitem>
- </itemizedlist>
- The last two states are seen only when
- <xref linkend="guc-max-slot-wal-keep-size"/> is
- non-negative. If <structfield>restart_lsn</structfield> is NULL, this
- field is null.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>safe_wal_size</structfield> <type>int8</type>
- </para>
- <para>
- The number of bytes that can be written to WAL such that this slot
- is not in danger of getting in state "lost". It is NULL for lost
- slots, as well as if <varname>max_slot_wal_keep_size</varname>
- is <literal>-1</literal>.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>two_phase</structfield> <type>bool</type>
- </para>
- <para>
- True if the slot is enabled for decoding prepared transactions. Always
- false for physical slots.
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
- </sect1>
-
- <sect1 id="view-pg-roles">
- <title><structname>pg_roles</structname></title>
-
- <indexterm zone="view-pg-roles">
- <primary>pg_roles</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_roles</structname> provides access to
- information about database roles. This is simply a publicly
- readable view of
- <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>
- that blanks out the password field.
- </para>
-
- <table>
- <title><structname>pg_roles</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>rolname</structfield> <type>name</type>
- </para>
- <para>
- Role name
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>rolsuper</structfield> <type>bool</type>
- </para>
- <para>
- Role has superuser privileges
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>rolinherit</structfield> <type>bool</type>
- </para>
- <para>
- Role automatically inherits privileges of roles it is a
- member of
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>rolcreaterole</structfield> <type>bool</type>
- </para>
- <para>
- Role can create more roles
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>rolcreatedb</structfield> <type>bool</type>
- </para>
- <para>
- Role can create databases
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>rolcanlogin</structfield> <type>bool</type>
- </para>
- <para>
- Role can log in. That is, this role can be given as the initial
- session authorization identifier
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>rolreplication</structfield> <type>bool</type>
- </para>
- <para>
- Role is a replication role. A replication role can initiate replication
- connections and create and drop replication slots.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>rolconnlimit</structfield> <type>int4</type>
- </para>
- <para>
- For roles that can log in, this sets maximum number of concurrent
- connections this role can make. -1 means no limit.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>rolpassword</structfield> <type>text</type>
- </para>
- <para>
- Not the password (always reads as <literal>********</literal>)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>rolvaliduntil</structfield> <type>timestamptz</type>
- </para>
- <para>
- Password expiry time (only used for password authentication);
- null if no expiration
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>rolbypassrls</structfield> <type>bool</type>
- </para>
- <para>
- Role bypasses every row-level security policy, see
- <xref linkend="ddl-rowsecurity"/> for more information.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>rolconfig</structfield> <type>text[]</type>
- </para>
- <para>
- Role-specific defaults for run-time configuration variables
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>oid</structfield> <type>oid</type>
- (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>oid</structfield>)
- </para>
- <para>
- ID of role
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- </sect1>
-
- <sect1 id="view-pg-rules">
- <title><structname>pg_rules</structname></title>
-
- <indexterm zone="view-pg-rules">
- <primary>pg_rules</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_rules</structname> provides access to
- useful information about query rewrite rules.
- </para>
-
- <table>
- <title><structname>pg_rules</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>schemaname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
- </para>
- <para>
- Name of schema containing table
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>tablename</structfield> <type>name</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
- </para>
- <para>
- Name of table the rule is for
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>rulename</structfield> <type>name</type>
- (references <link linkend="catalog-pg-rewrite"><structname>pg_rewrite</structname></link>.<structfield>rulename</structfield>)
- </para>
- <para>
- Name of rule
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>definition</structfield> <type>text</type>
- </para>
- <para>
- Rule definition (a reconstructed creation command)
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- The <structname>pg_rules</structname> view excludes the <literal>ON SELECT</literal> rules
- of views and materialized views; those can be seen in
- <link linkend="view-pg-views"><structname>pg_views</structname></link> and <link linkend="view-pg-matviews"><structname>pg_matviews</structname></link>.
- </para>
-
- </sect1>
-
- <sect1 id="view-pg-seclabels">
- <title><structname>pg_seclabels</structname></title>
-
- <indexterm zone="view-pg-seclabels">
- <primary>pg_seclabels</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_seclabels</structname> provides information about
- security labels. It as an easier-to-query version of the
- <link linkend="catalog-pg-seclabel"><structname>pg_seclabel</structname></link> catalog.
- </para>
-
- <table>
- <title><structname>pg_seclabels</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>objoid</structfield> <type>oid</type>
- (references any OID column)
- </para>
- <para>
- The OID of the object this security label pertains to
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>classoid</structfield> <type>oid</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield>)
- </para>
- <para>
- The OID of the system catalog this object appears in
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>objsubid</structfield> <type>int4</type>
- </para>
- <para>
- For a security label on a table column, this is the column number (the
- <structfield>objoid</structfield> and <structfield>classoid</structfield> refer to
- the table itself). For all other object types, this column is
- zero.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>objtype</structfield> <type>text</type>
- </para>
- <para>
- The type of object to which this label applies, as text.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>objnamespace</structfield> <type>oid</type>
- (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>oid</structfield>)
- </para>
- <para>
- The OID of the namespace for this object, if applicable;
- otherwise NULL.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>objname</structfield> <type>text</type>
- </para>
- <para>
- The name of the object to which this label applies, as text.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>provider</structfield> <type>text</type>
- (references <link linkend="catalog-pg-seclabel"><structname>pg_seclabel</structname></link>.<structfield>provider</structfield>)
- </para>
- <para>
- The label provider associated with this label.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>label</structfield> <type>text</type>
- (references <link linkend="catalog-pg-seclabel"><structname>pg_seclabel</structname></link>.<structfield>label</structfield>)
- </para>
- <para>
- The security label applied to this object.
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
- </sect1>
-
- <sect1 id="view-pg-sequences">
- <title><structname>pg_sequences</structname></title>
-
- <indexterm zone="view-pg-sequences">
- <primary>pg_sequences</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_sequences</structname> provides access to
- useful information about each sequence in the database.
- </para>
-
- <table>
- <title><structname>pg_sequences</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>schemaname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
- </para>
- <para>
- Name of schema containing sequence
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>sequencename</structfield> <type>name</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
- </para>
- <para>
- Name of sequence
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>sequenceowner</structfield> <type>name</type>
- (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
- </para>
- <para>
- Name of sequence's owner
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>data_type</structfield> <type>regtype</type>
- (references <link linkend="catalog-pg-type"><structname>pg_type</structname></link>.<structfield>oid</structfield>)
- </para>
- <para>
- Data type of the sequence
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>start_value</structfield> <type>int8</type>
- </para>
- <para>
- Start value of the sequence
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>min_value</structfield> <type>int8</type>
- </para>
- <para>
- Minimum value of the sequence
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>max_value</structfield> <type>int8</type>
- </para>
- <para>
- Maximum value of the sequence
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>increment_by</structfield> <type>int8</type>
- </para>
- <para>
- Increment value of the sequence
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>cycle</structfield> <type>bool</type>
- </para>
- <para>
- Whether the sequence cycles
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>cache_size</structfield> <type>int8</type>
- </para>
- <para>
- Cache size of the sequence
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>last_value</structfield> <type>int8</type>
- </para>
- <para>
- The last sequence value written to disk. If caching is used,
- this value can be greater than the last value handed out from the
- sequence. Null if the sequence has not been read from yet. Also, if
- the current user does not have <literal>USAGE</literal>
- or <literal>SELECT</literal> privilege on the sequence, the value is
- null.
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
- </sect1>
-
- <sect1 id="view-pg-settings">
- <title><structname>pg_settings</structname></title>
-
- <indexterm zone="view-pg-settings">
- <primary>pg_settings</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_settings</structname> provides access to
- run-time parameters of the server. It is essentially an alternative
- interface to the <link linkend="sql-show"><command>SHOW</command></link>
- and <link linkend="sql-set"><command>SET</command></link> commands.
- It also provides access to some facts about each parameter that are
- not directly available from <link linkend="sql-show"><command>SHOW</command></link>, such as minimum and
- maximum values.
- </para>
-
- <table>
- <title><structname>pg_settings</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>name</structfield> <type>text</type>
- </para>
- <para>
- Run-time configuration parameter name
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>setting</structfield> <type>text</type>
- </para>
- <para>
- Current value of the parameter
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>unit</structfield> <type>text</type>
- </para>
- <para>
- Implicit unit of the parameter
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>category</structfield> <type>text</type>
- </para>
- <para>
- Logical group of the parameter
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>short_desc</structfield> <type>text</type>
- </para>
- <para>
- A brief description of the parameter
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>extra_desc</structfield> <type>text</type>
- </para>
- <para>
- Additional, more detailed, description of the parameter
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>context</structfield> <type>text</type>
- </para>
- <para>
- Context required to set the parameter's value (see below)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>vartype</structfield> <type>text</type>
- </para>
- <para>
- Parameter type (<literal>bool</literal>, <literal>enum</literal>,
- <literal>integer</literal>, <literal>real</literal>, or <literal>string</literal>)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>source</structfield> <type>text</type>
- </para>
- <para>
- Source of the current parameter value
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>min_val</structfield> <type>text</type>
- </para>
- <para>
- Minimum allowed value of the parameter (null for non-numeric
- values)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>max_val</structfield> <type>text</type>
- </para>
- <para>
- Maximum allowed value of the parameter (null for non-numeric
- values)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>enumvals</structfield> <type>text[]</type>
- </para>
- <para>
- Allowed values of an enum parameter (null for non-enum
- values)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>boot_val</structfield> <type>text</type>
- </para>
- <para>
- Parameter value assumed at server startup if the parameter is
- not otherwise set
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>reset_val</structfield> <type>text</type>
- </para>
- <para>
- Value that <link linkend="sql-reset"><command>RESET</command></link> would reset the parameter to
- in the current session
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>sourcefile</structfield> <type>text</type>
- </para>
- <para>
- Configuration file the current value was set in (null for
- values set from sources other than configuration files, or when
- examined by a user who neither is a superuser nor has privileges of
- <literal>pg_read_all_settings</literal>); helpful when using
- <literal>include</literal> directives in configuration files
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>sourceline</structfield> <type>int4</type>
- </para>
- <para>
- Line number within the configuration file the current value was
- set at (null for values set from sources other than configuration files,
- or when examined by a user who neither is a superuser nor has privileges of
- <literal>pg_read_all_settings</literal>).
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>pending_restart</structfield> <type>bool</type>
- </para>
- <para>
- <literal>true</literal> if the value has been changed in the
- configuration file but needs a restart; or <literal>false</literal>
- otherwise.
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- There are several possible values of <structfield>context</structfield>.
- In order of decreasing difficulty of changing the setting, they are:
- </para>
-
- <variablelist>
- <varlistentry>
- <!-- PGC_INTERNAL -->
- <term><literal>internal</literal></term>
- <listitem>
- <para>
- These settings cannot be changed directly; they reflect internally
- determined values. Some of them may be adjustable by rebuilding the
- server with different configuration options, or by changing options
- supplied to <application>initdb</application>.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <!-- PGC_POSTMASTER -->
- <term><literal>postmaster</literal></term>
- <listitem>
- <para>
- These settings can only be applied when the server starts, so any change
- requires restarting the server. Values for these settings are typically
- stored in the <filename>postgresql.conf</filename> file, or passed on
- the command line when starting the server. Of course, settings with any
- of the lower <structfield>context</structfield> types can also be
- set at server start time.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <!-- PGC_SIGHUP -->
- <term><literal>sighup</literal></term>
- <listitem>
- <para>
- Changes to these settings can be made in
- <filename>postgresql.conf</filename> without restarting the server.
- Send a <systemitem>SIGHUP</systemitem> signal to the postmaster to
- cause it to re-read <filename>postgresql.conf</filename> and apply
- the changes. The postmaster will also forward the
- <systemitem>SIGHUP</systemitem> signal to its child processes so that
- they all pick up the new value.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <!-- PGC_SU_BACKEND -->
- <term><literal>superuser-backend</literal></term>
- <listitem>
- <para>
- Changes to these settings can be made in
- <filename>postgresql.conf</filename> without restarting the server.
- They can also be set for a particular session in the connection request
- packet (for example, via <application>libpq</application>'s <literal>PGOPTIONS</literal>
- environment variable), but only if the connecting user is a superuser
- or has been granted the appropriate <literal>SET</literal> privilege.
- However, these settings never change in a session after it is started.
- If you change them in <filename>postgresql.conf</filename>, send a
- <systemitem>SIGHUP</systemitem> signal to the postmaster to cause it to
- re-read <filename>postgresql.conf</filename>. The new values will only
- affect subsequently-launched sessions.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <!-- PGC_BACKEND -->
- <term><literal>backend</literal></term>
- <listitem>
- <para>
- Changes to these settings can be made in
- <filename>postgresql.conf</filename> without restarting the server.
- They can also be set for a particular session in the connection request
- packet (for example, via <application>libpq</application>'s <literal>PGOPTIONS</literal>
- environment variable); any user can make such a change for their session.
- However, these settings never change in a session after it is started.
- If you change them in <filename>postgresql.conf</filename>, send a
- <systemitem>SIGHUP</systemitem> signal to the postmaster to cause it to
- re-read <filename>postgresql.conf</filename>. The new values will only
- affect subsequently-launched sessions.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <!-- PGC_SUSET -->
- <term><literal>superuser</literal></term>
- <listitem>
- <para>
- These settings can be set from <filename>postgresql.conf</filename>,
- or within a session via the <command>SET</command> command; but only superusers
- and users with the appropriate <literal>SET</literal> privilege
- can change them via <command>SET</command>. Changes in
- <filename>postgresql.conf</filename> will affect existing sessions
- only if no session-local value has been established with <command>SET</command>.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <!-- PGC_USERSET -->
- <term><literal>user</literal></term>
- <listitem>
- <para>
- These settings can be set from <filename>postgresql.conf</filename>,
- or within a session via the <command>SET</command> command. Any user is
- allowed to change their session-local value. Changes in
- <filename>postgresql.conf</filename> will affect existing sessions
- only if no session-local value has been established with <command>SET</command>.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
-
- <para>
- See <xref linkend="config-setting"/> for more information about the various
- ways to change these parameters.
- </para>
-
- <para>
- This view does not display <link linkend="runtime-config-custom">customized options</link>
- until the extension module that defines them has been loaded.
- </para>
-
- <para>
- This view cannot be inserted into or deleted from, but it can be updated. An
- <command>UPDATE</command> applied to a row of <structname>pg_settings</structname>
- is equivalent to executing the <command>SET</command> command on that named
- parameter. The change only affects the value used by the current
- session. If an <command>UPDATE</command> is issued within a transaction
- that is later aborted, the effects of the <command>UPDATE</command> command
- disappear when the transaction is rolled back. Once the surrounding
- transaction is committed, the effects will persist until the end of the
- session, unless overridden by another <command>UPDATE</command> or
- <command>SET</command>.
- </para>
-
- </sect1>
-
- <sect1 id="view-pg-shadow">
- <title><structname>pg_shadow</structname></title>
-
- <indexterm zone="view-pg-shadow">
- <primary>pg_shadow</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_shadow</structname> exists for backwards
- compatibility: it emulates a catalog that existed in
- <productname>PostgreSQL</productname> before version 8.1.
- It shows properties of all roles that are marked as
- <structfield>rolcanlogin</structfield> in
- <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.
- </para>
-
- <para>
- The name stems from the fact that this table
- should not be readable by the public since it contains passwords.
- <link linkend="view-pg-user"><structname>pg_user</structname></link>
- is a publicly readable view on
- <structname>pg_shadow</structname> that blanks out the password field.
- </para>
-
- <table>
- <title><structname>pg_shadow</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>usename</structfield> <type>name</type>
- (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
- </para>
- <para>
- User name
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>usesysid</structfield> <type>oid</type>
- (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>oid</structfield>)
- </para>
- <para>
- ID of this user
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>usecreatedb</structfield> <type>bool</type>
- </para>
- <para>
- User can create databases
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>usesuper</structfield> <type>bool</type>
- </para>
- <para>
- User is a superuser
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>userepl</structfield> <type>bool</type>
- </para>
- <para>
- User can initiate streaming replication and put the system in and
- out of backup mode.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>usebypassrls</structfield> <type>bool</type>
- </para>
- <para>
- User bypasses every row-level security policy, see
- <xref linkend="ddl-rowsecurity"/> for more information.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>passwd</structfield> <type>text</type>
- </para>
- <para>
- Password (possibly encrypted); null if none. See
- <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>
- for details of how encrypted passwords are stored.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>valuntil</structfield> <type>timestamptz</type>
- </para>
- <para>
- Password expiry time (only used for password authentication)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>useconfig</structfield> <type>text[]</type>
- </para>
- <para>
- Session defaults for run-time configuration variables
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- </sect1>
-
- <sect1 id="view-pg-shmem-allocations">
- <title><structname>pg_shmem_allocations</structname></title>
-
- <indexterm zone="view-pg-shmem-allocations">
- <primary>pg_shmem_allocations</primary>
- </indexterm>
-
- <para>
- The <structname>pg_shmem_allocations</structname> view shows allocations
- made from the server's main shared memory segment. This includes both
- memory allocated by <productname>PostgreSQL</productname> itself and memory
- allocated by extensions using the mechanisms detailed in
- <xref linkend="xfunc-shared-addin" />.
- </para>
-
- <para>
- Note that this view does not include memory allocated using the dynamic
- shared memory infrastructure.
- </para>
-
- <table>
- <title><structname>pg_shmem_allocations</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>name</structfield> <type>text</type>
- </para>
- <para>
- The name of the shared memory allocation. NULL for unused memory
- and <literal><anonymous></literal> for anonymous
- allocations.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>off</structfield> <type>int8</type>
- </para>
- <para>
- The offset at which the allocation starts. NULL for anonymous
- allocations, since details related to them are not known.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>size</structfield> <type>int8</type>
- </para>
- <para>
- Size of the allocation
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>allocated_size</structfield> <type>int8</type>
- </para>
- <para>
- Size of the allocation including padding. For anonymous
- allocations, no information about padding is available, so the
- <literal>size</literal> and <literal>allocated_size</literal> columns
- will always be equal. Padding is not meaningful for free memory, so
- the columns will be equal in that case also.
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- Anonymous allocations are allocations that have been made
- with <literal>ShmemAlloc()</literal> directly, rather than via
- <literal>ShmemInitStruct()</literal> or
- <literal>ShmemInitHash()</literal>.
- </para>
-
- <para>
- By default, the <structname>pg_shmem_allocations</structname> view can be
- read only by superusers or roles with privileges of the
- <literal>pg_read_all_stats</literal> role.
- </para>
- </sect1>
-
- <sect1 id="view-pg-stats">
- <title><structname>pg_stats</structname></title>
-
- <indexterm zone="view-pg-stats">
- <primary>pg_stats</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_stats</structname> provides access to
- the information stored in the <link
- linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link>
- catalog. This view allows access only to rows of
- <link linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link> that correspond to tables the
- user has permission to read, and therefore it is safe to allow public
- read access to this view.
- </para>
-
- <para>
- <structname>pg_stats</structname> is also designed to present the
- information in a more readable format than the underlying catalog
- — at the cost that its schema must be extended whenever new slot types
- are defined for <link linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link>.
- </para>
-
- <table>
- <title><structname>pg_stats</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>schemaname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
- </para>
- <para>
- Name of schema containing table
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>tablename</structfield> <type>name</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
- </para>
- <para>
- Name of table
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>attname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>.<structfield>attname</structfield>)
- </para>
- <para>
- Name of column described by this row
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>inherited</structfield> <type>bool</type>
- </para>
- <para>
- If true, this row includes inheritance child columns, not just the
- values in the specified table
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>null_frac</structfield> <type>float4</type>
- </para>
- <para>
- Fraction of column entries that are null
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>avg_width</structfield> <type>int4</type>
- </para>
- <para>
- Average width in bytes of column's entries
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>n_distinct</structfield> <type>float4</type>
- </para>
- <para>
- If greater than zero, the estimated number of distinct values in the
- column. If less than zero, the negative of the number of distinct
- values divided by the number of rows. (The negated form is used when
- <command>ANALYZE</command> believes that the number of distinct values is
- likely to increase as the table grows; the positive form is used when
- the column seems to have a fixed number of possible values.) For
- example, -1 indicates a unique column in which the number of distinct
- values is the same as the number of rows.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>most_common_vals</structfield> <type>anyarray</type>
- </para>
- <para>
- A list of the most common values in the column. (Null if
- no values seem to be more common than any others.)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>most_common_freqs</structfield> <type>float4[]</type>
- </para>
- <para>
- A list of the frequencies of the most common values,
- i.e., number of occurrences of each divided by total number of rows.
- (Null when <structfield>most_common_vals</structfield> is.)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>histogram_bounds</structfield> <type>anyarray</type>
- </para>
- <para>
- A list of values that divide the column's values into groups of
- approximately equal population. The values in
- <structfield>most_common_vals</structfield>, if present, are omitted from this
- histogram calculation. (This column is null if the column data type
- does not have a <literal><</literal> operator or if the
- <structfield>most_common_vals</structfield> list accounts for the entire
- population.)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>correlation</structfield> <type>float4</type>
- </para>
- <para>
- Statistical correlation between physical row ordering and
- logical ordering of the column values. This ranges from -1 to +1.
- When the value is near -1 or +1, an index scan on the column will
- be estimated to be cheaper than when it is near zero, due to reduction
- of random access to the disk. (This column is null if the column data
- type does not have a <literal><</literal> operator.)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>most_common_elems</structfield> <type>anyarray</type>
- </para>
- <para>
- A list of non-null element values most often appearing within values of
- the column. (Null for scalar types.)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>most_common_elem_freqs</structfield> <type>float4[]</type>
- </para>
- <para>
- A list of the frequencies of the most common element values, i.e., the
- fraction of rows containing at least one instance of the given value.
- Two or three additional values follow the per-element frequencies;
- these are the minimum and maximum of the preceding per-element
- frequencies, and optionally the frequency of null elements.
- (Null when <structfield>most_common_elems</structfield> is.)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>elem_count_histogram</structfield> <type>float4[]</type>
- </para>
- <para>
- A histogram of the counts of distinct non-null element values within the
- values of the column, followed by the average number of distinct
- non-null elements. (Null for scalar types.)
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- The maximum number of entries in the array fields can be controlled on a
- column-by-column basis using the <link linkend="sql-altertable"><command>ALTER
- TABLE SET STATISTICS</command></link>
- command, or globally by setting the
- <xref linkend="guc-default-statistics-target"/> run-time parameter.
- </para>
-
- </sect1>
-
- <sect1 id="view-pg-stats-ext">
- <title><structname>pg_stats_ext</structname></title>
-
- <indexterm zone="view-pg-stats-ext">
- <primary>pg_stats_ext</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_stats_ext</structname> provides access to
- information about each extended statistics object in the database,
- combining information stored in the <link
- linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>
- and <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>
- catalogs. This view allows access only to rows of
- <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link> and <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>
- that correspond to tables the user has permission to read, and therefore
- it is safe to allow public read access to this view.
- </para>
-
- <para>
- <structname>pg_stats_ext</structname> is also designed to present the
- information in a more readable format than the underlying catalogs
- — at the cost that its schema must be extended whenever new types
- of extended statistics are added to <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>.
- </para>
-
- <table>
- <title><structname>pg_stats_ext</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>schemaname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
- </para>
- <para>
- Name of schema containing table
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>tablename</structfield> <type>name</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
- </para>
- <para>
- Name of table
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>statistics_schemaname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
- </para>
- <para>
- Name of schema containing extended statistics object
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>statistics_name</structfield> <type>name</type>
- (references <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>.<structfield>stxname</structfield>)
- </para>
- <para>
- Name of extended statistics object
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>statistics_owner</structfield> <type>name</type>
- (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
- </para>
- <para>
- Owner of the extended statistics object
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>attnames</structfield> <type>name[]</type>
- (references <link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>.<structfield>attname</structfield>)
- </para>
- <para>
- Names of the columns included in the extended statistics object
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>exprs</structfield> <type>text[]</type>
- </para>
- <para>
- Expressions included in the extended statistics object
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>kinds</structfield> <type>char[]</type>
- </para>
- <para>
- Types of extended statistics object enabled for this record
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>inherited</structfield> <type>bool</type>
- (references <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>.<structfield>stxdinherit</structfield>)
- </para>
- <para>
- If true, the stats include inheritance child columns, not just the
- values in the specified relation
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>n_distinct</structfield> <type>pg_ndistinct</type>
- </para>
- <para>
- N-distinct counts for combinations of column values. If greater
- than zero, the estimated number of distinct values in the combination.
- If less than zero, the negative of the number of distinct values divided
- by the number of rows.
- (The negated form is used when <command>ANALYZE</command> believes that
- the number of distinct values is likely to increase as the table grows;
- the positive form is used when the column seems to have a fixed number
- of possible values.) For example, -1 indicates a unique combination of
- columns in which the number of distinct combinations is the same as the
- number of rows.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>dependencies</structfield> <type>pg_dependencies</type>
- </para>
- <para>
- Functional dependency statistics
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>most_common_vals</structfield> <type>text[]</type>
- </para>
- <para>
- A list of the most common combinations of values in the columns.
- (Null if no combinations seem to be more common than any others.)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>most_common_val_nulls</structfield> <type>bool[]</type>
- </para>
- <para>
- A list of NULL flags for the most common combinations of values.
- (Null when <structfield>most_common_vals</structfield> is.)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>most_common_freqs</structfield> <type>float8[]</type>
- </para>
- <para>
- A list of the frequencies of the most common combinations,
- i.e., number of occurrences of each divided by total number of rows.
- (Null when <structfield>most_common_vals</structfield> is.)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>most_common_base_freqs</structfield> <type>float8[]</type>
- </para>
- <para>
- A list of the base frequencies of the most common combinations,
- i.e., product of per-value frequencies.
- (Null when <structfield>most_common_vals</structfield> is.)
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- The maximum number of entries in the array fields can be controlled on a
- column-by-column basis using the <link linkend="sql-altertable"><command>ALTER
- TABLE SET STATISTICS</command></link> command, or globally by setting the
- <xref linkend="guc-default-statistics-target"/> run-time parameter.
- </para>
-
- </sect1>
-
- <sect1 id="view-pg-stats-ext-exprs">
- <title><structname>pg_stats_ext_exprs</structname></title>
-
- <indexterm zone="view-pg-stats-ext-exprs">
- <primary>pg_stats_ext_exprs</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_stats_ext_exprs</structname> provides access to
- information about all expressions included in extended statistics objects,
- combining information stored in the <link
- linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>
- and <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>
- catalogs. This view allows access only to rows of
- <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link> and <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>
- that correspond to tables the user has permission to read, and therefore
- it is safe to allow public read access to this view.
- </para>
-
- <para>
- <structname>pg_stats_ext_exprs</structname> is also designed to present
- the information in a more readable format than the underlying catalogs
- — at the cost that its schema must be extended whenever the structure
- of statistics in <structname>pg_statistic_ext</structname> changes.
- </para>
-
- <table>
- <title><structname>pg_stats_ext_exprs</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>schemaname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
- </para>
- <para>
- Name of schema containing table
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>tablename</structfield> <type>name</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
- </para>
- <para>
- Name of table the statistics object is defined on
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>statistics_schemaname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
- </para>
- <para>
- Name of schema containing extended statistics object
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>statistics_name</structfield> <type>name</type>
- (references <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>.<structfield>stxname</structfield>)
- </para>
- <para>
- Name of extended statistics object
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>statistics_owner</structfield> <type>name</type>
- (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
- </para>
- <para>
- Owner of the extended statistics object
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>expr</structfield> <type>text</type>
- </para>
- <para>
- Expression included in the extended statistics object
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>inherited</structfield> <type>bool</type>
- (references <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>.<structfield>stxdinherit</structfield>)
- </para>
- <para>
- If true, the stats include inheritance child columns, not just the
- values in the specified relation
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>null_frac</structfield> <type>float4</type>
- </para>
- <para>
- Fraction of expression entries that are null
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>avg_width</structfield> <type>int4</type>
- </para>
- <para>
- Average width in bytes of expression's entries
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>n_distinct</structfield> <type>float4</type>
- </para>
- <para>
- If greater than zero, the estimated number of distinct values in the
- expression. If less than zero, the negative of the number of distinct
- values divided by the number of rows. (The negated form is used when
- <command>ANALYZE</command> believes that the number of distinct values is
- likely to increase as the table grows; the positive form is used when
- the expression seems to have a fixed number of possible values.) For
- example, -1 indicates a unique expression in which the number of distinct
- values is the same as the number of rows.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>most_common_vals</structfield> <type>anyarray</type>
- </para>
- <para>
- A list of the most common values in the expression. (Null if
- no values seem to be more common than any others.)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>most_common_freqs</structfield> <type>float4[]</type>
- </para>
- <para>
- A list of the frequencies of the most common values,
- i.e., number of occurrences of each divided by total number of rows.
- (Null when <structfield>most_common_vals</structfield> is.)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>histogram_bounds</structfield> <type>anyarray</type>
- </para>
- <para>
- A list of values that divide the expression's values into groups of
- approximately equal population. The values in
- <structfield>most_common_vals</structfield>, if present, are omitted from this
- histogram calculation. (This expression is null if the expression data type
- does not have a <literal><</literal> operator or if the
- <structfield>most_common_vals</structfield> list accounts for the entire
- population.)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>correlation</structfield> <type>float4</type>
- </para>
- <para>
- Statistical correlation between physical row ordering and
- logical ordering of the expression values. This ranges from -1 to +1.
- When the value is near -1 or +1, an index scan on the expression will
- be estimated to be cheaper than when it is near zero, due to reduction
- of random access to the disk. (This expression is null if the expression's
- data type does not have a <literal><</literal> operator.)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>most_common_elems</structfield> <type>anyarray</type>
- </para>
- <para>
- A list of non-null element values most often appearing within values of
- the expression. (Null for scalar types.)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>most_common_elem_freqs</structfield> <type>float4[]</type>
- </para>
- <para>
- A list of the frequencies of the most common element values, i.e., the
- fraction of rows containing at least one instance of the given value.
- Two or three additional values follow the per-element frequencies;
- these are the minimum and maximum of the preceding per-element
- frequencies, and optionally the frequency of null elements.
- (Null when <structfield>most_common_elems</structfield> is.)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>elem_count_histogram</structfield> <type>float4[]</type>
- </para>
- <para>
- A histogram of the counts of distinct non-null element values within the
- values of the expression, followed by the average number of distinct
- non-null elements. (Null for scalar types.)
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- The maximum number of entries in the array fields can be controlled on a
- column-by-column basis using the <link linkend="sql-altertable"><command>ALTER
- TABLE SET STATISTICS</command></link> command, or globally by setting the
- <xref linkend="guc-default-statistics-target"/> run-time parameter.
- </para>
-
- </sect1>
-
- <sect1 id="view-pg-tables">
- <title><structname>pg_tables</structname></title>
-
- <indexterm zone="view-pg-tables">
- <primary>pg_tables</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_tables</structname> provides access to
- useful information about each table in the database.
- </para>
-
- <table>
- <title><structname>pg_tables</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>schemaname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
- </para>
- <para>
- Name of schema containing table
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>tablename</structfield> <type>name</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
- </para>
- <para>
- Name of table
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>tableowner</structfield> <type>name</type>
- (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
- </para>
- <para>
- Name of table's owner
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>tablespace</structfield> <type>name</type>
- (references <link linkend="catalog-pg-tablespace"><structname>pg_tablespace</structname></link>.<structfield>spcname</structfield>)
- </para>
- <para>
- Name of tablespace containing table (null if default for database)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>hasindexes</structfield> <type>bool</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relhasindex</structfield>)
- </para>
- <para>
- True if table has (or recently had) any indexes
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>hasrules</structfield> <type>bool</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relhasrules</structfield>)
- </para>
- <para>
- True if table has (or once had) rules
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>hastriggers</structfield> <type>bool</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relhastriggers</structfield>)
- </para>
- <para>
- True if table has (or once had) triggers
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>rowsecurity</structfield> <type>bool</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relrowsecurity</structfield>)
- </para>
- <para>
- True if row security is enabled on the table
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- </sect1>
-
- <sect1 id="view-pg-timezone-abbrevs">
- <title><structname>pg_timezone_abbrevs</structname></title>
-
- <indexterm zone="view-pg-timezone-abbrevs">
- <primary>pg_timezone_abbrevs</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_timezone_abbrevs</structname> provides a list
- of time zone abbreviations that are currently recognized by the datetime
- input routines. The contents of this view change when the
- <xref linkend="guc-timezone-abbreviations"/> run-time parameter is modified.
- </para>
-
- <table>
- <title><structname>pg_timezone_abbrevs</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>abbrev</structfield> <type>text</type>
- </para>
- <para>
- Time zone abbreviation
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>utc_offset</structfield> <type>interval</type>
- </para>
- <para>
- Offset from UTC (positive means east of Greenwich)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>is_dst</structfield> <type>bool</type>
- </para>
- <para>
- True if this is a daylight-savings abbreviation
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- While most timezone abbreviations represent fixed offsets from UTC,
- there are some that have historically varied in value
- (see <xref linkend="datetime-config-files"/> for more information).
- In such cases this view presents their current meaning.
- </para>
-
- </sect1>
-
- <sect1 id="view-pg-timezone-names">
- <title><structname>pg_timezone_names</structname></title>
-
- <indexterm zone="view-pg-timezone-names">
- <primary>pg_timezone_names</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_timezone_names</structname> provides a list
- of time zone names that are recognized by <command>SET TIMEZONE</command>,
- along with their associated abbreviations, UTC offsets,
- and daylight-savings status. (Technically,
- <productname>PostgreSQL</productname> does not use UTC because leap
- seconds are not handled.)
- Unlike the abbreviations shown in <link
- linkend="view-pg-timezone-abbrevs"><structname>pg_timezone_abbrevs</structname></link>, many of these names imply a set of daylight-savings transition
- date rules. Therefore, the associated information changes across local DST
- boundaries. The displayed information is computed based on the current
- value of <function>CURRENT_TIMESTAMP</function>.
- </para>
-
- <table>
- <title><structname>pg_timezone_names</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>name</structfield> <type>text</type>
- </para>
- <para>
- Time zone name
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>abbrev</structfield> <type>text</type>
- </para>
- <para>
- Time zone abbreviation
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>utc_offset</structfield> <type>interval</type>
- </para>
- <para>
- Offset from UTC (positive means east of Greenwich)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>is_dst</structfield> <type>bool</type>
- </para>
- <para>
- True if currently observing daylight savings
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- </sect1>
-
- <sect1 id="view-pg-user">
- <title><structname>pg_user</structname></title>
-
- <indexterm zone="view-pg-user">
- <primary>pg_user</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_user</structname> provides access to
- information about database users. This is simply a publicly
- readable view of
- <link linkend="view-pg-shadow"><structname>pg_shadow</structname></link>
- that blanks out the password field.
- </para>
-
- <table>
- <title><structname>pg_user</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>usename</structfield> <type>name</type>
- </para>
- <para>
- User name
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>usesysid</structfield> <type>oid</type>
- </para>
- <para>
- ID of this user
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>usecreatedb</structfield> <type>bool</type>
- </para>
- <para>
- User can create databases
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>usesuper</structfield> <type>bool</type>
- </para>
- <para>
- User is a superuser
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>userepl</structfield> <type>bool</type>
- </para>
- <para>
- User can initiate streaming replication and put the system in and
- out of backup mode.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>usebypassrls</structfield> <type>bool</type>
- </para>
- <para>
- User bypasses every row-level security policy, see
- <xref linkend="ddl-rowsecurity"/> for more information.
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>passwd</structfield> <type>text</type>
- </para>
- <para>
- Not the password (always reads as <literal>********</literal>)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>valuntil</structfield> <type>timestamptz</type>
- </para>
- <para>
- Password expiry time (only used for password authentication)
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>useconfig</structfield> <type>text[]</type>
- </para>
- <para>
- Session defaults for run-time configuration variables
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- </sect1>
-
- <sect1 id="view-pg-user-mappings">
- <title><structname>pg_user_mappings</structname></title>
-
- <indexterm zone="view-pg-user-mappings">
- <primary>pg_user_mappings</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_user_mappings</structname> provides access
- to information about user mappings. This is essentially a publicly
- readable view of
- <link linkend="catalog-pg-user-mapping"><structname>pg_user_mapping</structname></link>
- that leaves out the options field if the user has no rights to use
- it.
- </para>
-
- <table>
- <title><structname>pg_user_mappings</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>umid</structfield> <type>oid</type>
- (references <link linkend="catalog-pg-user-mapping"><structname>pg_user_mapping</structname></link>.<structfield>oid</structfield>)
- </para>
- <para>
- OID of the user mapping
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>srvid</structfield> <type>oid</type>
- (references <link linkend="catalog-pg-foreign-server"><structname>pg_foreign_server</structname></link>.<structfield>oid</structfield>)
- </para>
- <para>
- The OID of the foreign server that contains this mapping
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>srvname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-foreign-server"><structname>pg_foreign_server</structname></link>.<structfield>srvname</structfield>)
- </para>
- <para>
- Name of the foreign server
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>umuser</structfield> <type>oid</type>
- (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>oid</structfield>)
- </para>
- <para>
- OID of the local role being mapped, or zero if the user mapping is public
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>usename</structfield> <type>name</type>
- </para>
- <para>
- Name of the local user to be mapped
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>umoptions</structfield> <type>text[]</type>
- </para>
- <para>
- User mapping specific options, as <quote>keyword=value</quote> strings
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- <para>
- To protect password information stored as a user mapping option,
- the <structfield>umoptions</structfield> column will read as null
- unless one of the following applies:
- <itemizedlist>
- <listitem>
- <para>
- current user is the user being mapped, and owns the server or
- holds <literal>USAGE</literal> privilege on it
- </para>
- </listitem>
- <listitem>
- <para>
- current user is the server owner and mapping is for <literal>PUBLIC</literal>
- </para>
- </listitem>
- <listitem>
- <para>
- current user is a superuser
- </para>
- </listitem>
- </itemizedlist>
- </para>
-
- </sect1>
-
-
- <sect1 id="view-pg-views">
- <title><structname>pg_views</structname></title>
-
- <indexterm zone="view-pg-views">
- <primary>pg_views</primary>
- </indexterm>
-
- <para>
- The view <structname>pg_views</structname> provides access to
- useful information about each view in the database.
- </para>
-
- <table>
- <title><structname>pg_views</structname> Columns</title>
- <tgroup cols="1">
- <thead>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- Column Type
- </para>
- <para>
- Description
- </para></entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>schemaname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
- </para>
- <para>
- Name of schema containing view
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>viewname</structfield> <type>name</type>
- (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
- </para>
- <para>
- Name of view
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>viewowner</structfield> <type>name</type>
- (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
- </para>
- <para>
- Name of view's owner
- </para></entry>
- </row>
-
- <row>
- <entry role="catalog_table_entry"><para role="column_definition">
- <structfield>definition</structfield> <type>text</type>
- </para>
- <para>
- View definition (a reconstructed <xref linkend="sql-select"/> query)
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
- </sect1>
-
</chapter>
--- /dev/null
+<!-- doc/src/sgml/system-views.sgml -->
+<!--
+ Documentation of the system views, directed toward PostgreSQL developers
+ -->
+
+<chapter id="views">
+ <title>System Views</title>
+
+ <para>
+ In addition to the system catalogs, <productname>PostgreSQL</productname>
+ provides a number of built-in views. Some system views provide convenient
+ access to some commonly used queries on the system catalogs. Other views
+ provide access to internal server state.
+ </para>
+
+ <para>
+ The information schema (<xref linkend="information-schema"/>) provides
+ an alternative set of views which overlap the functionality of the system
+ views. Since the information schema is SQL-standard whereas the views
+ described here are <productname>PostgreSQL</productname>-specific,
+ it's usually better to use the information schema if it provides all
+ the information you need.
+ </para>
+
+ <para>
+ <xref linkend="view-table"/> lists the system views described here.
+ More detailed documentation of each view follows below.
+ There are some additional views that provide access to accumulated
+ statistics; they are described in
+ <xref linkend="monitoring-stats-views-table"/>.
+ </para>
+
+ <sect1 id="views-overview">
+ <title>Overview</title>
+
+ <para>
+ <xref linkend="view-table"/> lists the system views.
+ More detailed documentation of each catalog follows below.
+ Except where noted, all the views described here are read-only.
+ </para>
+
+ <table id="view-table">
+ <title>System Views</title>
+
+ <tgroup cols="2">
+ <thead>
+ <row>
+ <entry>View Name</entry>
+ <entry>Purpose</entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry><link linkend="view-pg-available-extensions"><structname>pg_available_extensions</structname></link></entry>
+ <entry>available extensions</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-available-extension-versions"><structname>pg_available_extension_versions</structname></link></entry>
+ <entry>available versions of extensions</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-backend-memory-contexts"><structname>pg_backend_memory_contexts</structname></link></entry>
+ <entry>backend memory contexts</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-config"><structname>pg_config</structname></link></entry>
+ <entry>compile-time configuration parameters</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-cursors"><structname>pg_cursors</structname></link></entry>
+ <entry>open cursors</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-file-settings"><structname>pg_file_settings</structname></link></entry>
+ <entry>summary of configuration file contents</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-group"><structname>pg_group</structname></link></entry>
+ <entry>groups of database users</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-hba-file-rules"><structname>pg_hba_file_rules</structname></link></entry>
+ <entry>summary of client authentication configuration file contents</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-ident-file-mappings"><structname>pg_ident_file_mappings</structname></link></entry>
+ <entry>summary of client user name mapping configuration file contents</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-indexes"><structname>pg_indexes</structname></link></entry>
+ <entry>indexes</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-locks"><structname>pg_locks</structname></link></entry>
+ <entry>locks currently held or awaited</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-matviews"><structname>pg_matviews</structname></link></entry>
+ <entry>materialized views</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-policies"><structname>pg_policies</structname></link></entry>
+ <entry>policies</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-prepared-statements"><structname>pg_prepared_statements</structname></link></entry>
+ <entry>prepared statements</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-prepared-xacts"><structname>pg_prepared_xacts</structname></link></entry>
+ <entry>prepared transactions</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-publication-tables"><structname>pg_publication_tables</structname></link></entry>
+ <entry>publications and information of their associated tables</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-replication-origin-status"><structname>pg_replication_origin_status</structname></link></entry>
+ <entry>information about replication origins, including replication progress</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-replication-slots"><structname>pg_replication_slots</structname></link></entry>
+ <entry>replication slot information</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-roles"><structname>pg_roles</structname></link></entry>
+ <entry>database roles</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-rules"><structname>pg_rules</structname></link></entry>
+ <entry>rules</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-seclabels"><structname>pg_seclabels</structname></link></entry>
+ <entry>security labels</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-sequences"><structname>pg_sequences</structname></link></entry>
+ <entry>sequences</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-settings"><structname>pg_settings</structname></link></entry>
+ <entry>parameter settings</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-shadow"><structname>pg_shadow</structname></link></entry>
+ <entry>database users</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-shmem-allocations"><structname>pg_shmem_allocations</structname></link></entry>
+ <entry>shared memory allocations</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-stats"><structname>pg_stats</structname></link></entry>
+ <entry>planner statistics</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-stats-ext"><structname>pg_stats_ext</structname></link></entry>
+ <entry>extended planner statistics</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-stats-ext-exprs"><structname>pg_stats_ext_exprs</structname></link></entry>
+ <entry>extended planner statistics for expressions</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-tables"><structname>pg_tables</structname></link></entry>
+ <entry>tables</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-timezone-abbrevs"><structname>pg_timezone_abbrevs</structname></link></entry>
+ <entry>time zone abbreviations</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-timezone-names"><structname>pg_timezone_names</structname></link></entry>
+ <entry>time zone names</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-user"><structname>pg_user</structname></link></entry>
+ <entry>database users</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-user-mappings"><structname>pg_user_mappings</structname></link></entry>
+ <entry>user mappings</entry>
+ </row>
+
+ <row>
+ <entry><link linkend="view-pg-views"><structname>pg_views</structname></link></entry>
+ <entry>views</entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+ </sect1>
+
+ <sect1 id="view-pg-available-extensions">
+ <title><structname>pg_available_extensions</structname></title>
+
+ <indexterm zone="view-pg-available-extensions">
+ <primary>pg_available_extensions</primary>
+ </indexterm>
+
+ <para>
+ The <structname>pg_available_extensions</structname> view lists the
+ extensions that are available for installation.
+ See also the
+ <link linkend="catalog-pg-extension"><structname>pg_extension</structname></link>
+ catalog, which shows the extensions currently installed.
+ </para>
+
+ <table>
+ <title><structname>pg_available_extensions</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>name</structfield> <type>name</type>
+ </para>
+ <para>
+ Extension name
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>default_version</structfield> <type>text</type>
+ </para>
+ <para>
+ Name of default version, or <literal>NULL</literal> if none is
+ specified
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>installed_version</structfield> <type>text</type>
+ </para>
+ <para>
+ Currently installed version of the extension,
+ or <literal>NULL</literal> if not installed
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>comment</structfield> <type>text</type>
+ </para>
+ <para>
+ Comment string from the extension's control file
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ The <structname>pg_available_extensions</structname> view is read-only.
+ </para>
+ </sect1>
+
+ <sect1 id="view-pg-available-extension-versions">
+ <title><structname>pg_available_extension_versions</structname></title>
+
+ <indexterm zone="view-pg-available-extension-versions">
+ <primary>pg_available_extension_versions</primary>
+ </indexterm>
+
+ <para>
+ The <structname>pg_available_extension_versions</structname> view lists the
+ specific extension versions that are available for installation.
+ See also the <link
+ linkend="catalog-pg-extension"><structname>pg_extension</structname></link>
+ catalog, which shows the extensions currently installed.
+ </para>
+
+ <table>
+ <title><structname>pg_available_extension_versions</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>name</structfield> <type>name</type>
+ </para>
+ <para>
+ Extension name
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>version</structfield> <type>text</type>
+ </para>
+ <para>
+ Version name
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>installed</structfield> <type>bool</type>
+ </para>
+ <para>
+ True if this version of this extension is currently
+ installed
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>superuser</structfield> <type>bool</type>
+ </para>
+ <para>
+ True if only superusers are allowed to install this extension
+ (but see <structfield>trusted</structfield>)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>trusted</structfield> <type>bool</type>
+ </para>
+ <para>
+ True if the extension can be installed by non-superusers
+ with appropriate privileges
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>relocatable</structfield> <type>bool</type>
+ </para>
+ <para>
+ True if extension can be relocated to another schema
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>schema</structfield> <type>name</type>
+ </para>
+ <para>
+ Name of the schema that the extension must be installed into,
+ or <literal>NULL</literal> if partially or fully relocatable
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>requires</structfield> <type>name[]</type>
+ </para>
+ <para>
+ Names of prerequisite extensions,
+ or <literal>NULL</literal> if none
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>comment</structfield> <type>text</type>
+ </para>
+ <para>
+ Comment string from the extension's control file
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ The <structname>pg_available_extension_versions</structname> view is
+ read-only.
+ </para>
+ </sect1>
+
+ <sect1 id="view-pg-backend-memory-contexts">
+ <title><structname>pg_backend_memory_contexts</structname></title>
+
+ <indexterm zone="view-pg-backend-memory-contexts">
+ <primary>pg_backend_memory_contexts</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_backend_memory_contexts</structname> displays all
+ the memory contexts of the server process attached to the current session.
+ </para>
+ <para>
+ <structname>pg_backend_memory_contexts</structname> contains one row
+ for each memory context.
+ </para>
+
+ <table>
+ <title><structname>pg_backend_memory_contexts</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>name</structfield> <type>text</type>
+ </para>
+ <para>
+ Name of the memory context
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>ident</structfield> <type>text</type>
+ </para>
+ <para>
+ Identification information of the memory context. This field is truncated at 1024 bytes
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>parent</structfield> <type>text</type>
+ </para>
+ <para>
+ Name of the parent of this memory context
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>level</structfield> <type>int4</type>
+ </para>
+ <para>
+ Distance from TopMemoryContext in context tree
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>total_bytes</structfield> <type>int8</type>
+ </para>
+ <para>
+ Total bytes allocated for this memory context
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>total_nblocks</structfield> <type>int8</type>
+ </para>
+ <para>
+ Total number of blocks allocated for this memory context
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>free_bytes</structfield> <type>int8</type>
+ </para>
+ <para>
+ Free space in bytes
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>free_chunks</structfield> <type>int8</type>
+ </para>
+ <para>
+ Total number of free chunks
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>used_bytes</structfield> <type>int8</type>
+ </para>
+ <para>
+ Used space in bytes
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ By default, the <structname>pg_backend_memory_contexts</structname> view can be
+ read only by superusers or roles with the privileges of the
+ <literal>pg_read_all_stats</literal> role.
+ </para>
+ </sect1>
+
+ <sect1 id="view-pg-config">
+ <title><structname>pg_config</structname></title>
+
+ <indexterm zone="view-pg-config">
+ <primary>pg_config</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_config</structname> describes the
+ compile-time configuration parameters of the currently installed
+ version of <productname>PostgreSQL</productname>. It is intended, for example, to
+ be used by software packages that want to interface to
+ <productname>PostgreSQL</productname> to facilitate finding the required header
+ files and libraries. It provides the same basic information as the
+ <xref linkend="app-pgconfig"/> <productname>PostgreSQL</productname> client
+ application.
+ </para>
+
+ <para>
+ By default, the <structname>pg_config</structname> view can be read
+ only by superusers.
+ </para>
+
+ <table>
+ <title><structname>pg_config</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>name</structfield> <type>text</type>
+ </para>
+ <para>
+ The parameter name
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>setting</structfield> <type>text</type>
+ </para>
+ <para>
+ The parameter value
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ </sect1>
+
+ <sect1 id="view-pg-cursors">
+ <title><structname>pg_cursors</structname></title>
+
+ <indexterm zone="view-pg-cursors">
+ <primary>pg_cursors</primary>
+ </indexterm>
+
+ <para>
+ The <structname>pg_cursors</structname> view lists the cursors that
+ are currently available. Cursors can be defined in several ways:
+ <itemizedlist>
+ <listitem>
+ <para>
+ via the <link linkend="sql-declare"><command>DECLARE</command></link>
+ statement in SQL
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ via the Bind message in the frontend/backend protocol, as
+ described in <xref linkend="protocol-flow-ext-query"/>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ via the Server Programming Interface (SPI), as described in
+ <xref linkend="spi-interface"/>
+ </para>
+ </listitem>
+ </itemizedlist>
+
+ The <structname>pg_cursors</structname> view displays cursors
+ created by any of these means. Cursors only exist for the duration
+ of the transaction that defines them, unless they have been
+ declared <literal>WITH HOLD</literal>. Therefore non-holdable
+ cursors are only present in the view until the end of their
+ creating transaction.
+
+ <note>
+ <para>
+ Cursors are used internally to implement some of the components
+ of <productname>PostgreSQL</productname>, such as procedural languages.
+ Therefore, the <structname>pg_cursors</structname> view might include cursors
+ that have not been explicitly created by the user.
+ </para>
+ </note>
+ </para>
+
+ <table>
+ <title><structname>pg_cursors</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>name</structfield> <type>text</type>
+ </para>
+ <para>
+ The name of the cursor
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>statement</structfield> <type>text</type>
+ </para>
+ <para>
+ The verbatim query string submitted to declare this cursor
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>is_holdable</structfield> <type>bool</type>
+ </para>
+ <para>
+ <literal>true</literal> if the cursor is holdable (that is, it
+ can be accessed after the transaction that declared the cursor
+ has committed); <literal>false</literal> otherwise
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>is_binary</structfield> <type>bool</type>
+ </para>
+ <para>
+ <literal>true</literal> if the cursor was declared
+ <literal>BINARY</literal>; <literal>false</literal>
+ otherwise
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>is_scrollable</structfield> <type>bool</type>
+ </para>
+ <para>
+ <literal>true</literal> if the cursor is scrollable (that is, it
+ allows rows to be retrieved in a nonsequential manner);
+ <literal>false</literal> otherwise
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>creation_time</structfield> <type>timestamptz</type>
+ </para>
+ <para>
+ The time at which the cursor was declared
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ The <structname>pg_cursors</structname> view is read-only.
+ </para>
+
+ </sect1>
+
+ <sect1 id="view-pg-file-settings">
+ <title><structname>pg_file_settings</structname></title>
+
+ <indexterm zone="view-pg-file-settings">
+ <primary>pg_file_settings</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_file_settings</structname> provides a summary of
+ the contents of the server's configuration file(s). A row appears in
+ this view for each <quote>name = value</quote> entry appearing in the files,
+ with annotations indicating whether the value could be applied
+ successfully. Additional row(s) may appear for problems not linked to
+ a <quote>name = value</quote> entry, such as syntax errors in the files.
+ </para>
+
+ <para>
+ This view is helpful for checking whether planned changes in the
+ configuration files will work, or for diagnosing a previous failure.
+ Note that this view reports on the <emphasis>current</emphasis> contents of the
+ files, not on what was last applied by the server. (The
+ <link linkend="view-pg-settings"><structname>pg_settings</structname></link>
+ view is usually sufficient to determine that.)
+ </para>
+
+ <para>
+ By default, the <structname>pg_file_settings</structname> view can be read
+ only by superusers.
+ </para>
+
+ <table>
+ <title><structname>pg_file_settings</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>sourcefile</structfield> <type>text</type>
+ </para>
+ <para>
+ Full path name of the configuration file
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>sourceline</structfield> <type>int4</type>
+ </para>
+ <para>
+ Line number within the configuration file where the entry appears
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>seqno</structfield> <type>int4</type>
+ </para>
+ <para>
+ Order in which the entries are processed (1..<replaceable>n</replaceable>)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>name</structfield> <type>text</type>
+ </para>
+ <para>
+ Configuration parameter name
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>setting</structfield> <type>text</type>
+ </para>
+ <para>
+ Value to be assigned to the parameter
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>applied</structfield> <type>bool</type>
+ </para>
+ <para>
+ True if the value can be applied successfully
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>error</structfield> <type>text</type>
+ </para>
+ <para>
+ If not null, an error message indicating why this entry could
+ not be applied
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ If the configuration file contains syntax errors or invalid parameter
+ names, the server will not attempt to apply any settings from it, and
+ therefore all the <structfield>applied</structfield> fields will read as false.
+ In such a case there will be one or more rows with
+ non-null <structfield>error</structfield> fields indicating the
+ problem(s). Otherwise, individual settings will be applied if possible.
+ If an individual setting cannot be applied (e.g., invalid value, or the
+ setting cannot be changed after server start) it will have an appropriate
+ message in the <structfield>error</structfield> field. Another way that
+ an entry might have <structfield>applied</structfield> = false is that it is
+ overridden by a later entry for the same parameter name; this case is not
+ considered an error so nothing appears in
+ the <structfield>error</structfield> field.
+ </para>
+
+ <para>
+ See <xref linkend="config-setting"/> for more information about the various
+ ways to change run-time parameters.
+ </para>
+
+</sect1>
+
+ <sect1 id="view-pg-group">
+ <title><structname>pg_group</structname></title>
+
+ <indexterm zone="view-pg-group">
+ <primary>pg_group</primary>
+ </indexterm>
+
+ <!-- Unlike information_schema.applicable_roles, this shows no members for
+ pg_database_owner. The v8.1 catalog would have shown no members if
+ that role had existed at the time. -->
+ <para>
+ The view <structname>pg_group</structname> exists for backwards
+ compatibility: it emulates a catalog that existed in
+ <productname>PostgreSQL</productname> before version 8.1.
+ It shows the names and members of all roles that are marked as not
+ <structfield>rolcanlogin</structfield>, which is an approximation to the set
+ of roles that are being used as groups.
+ </para>
+
+ <table>
+ <title><structname>pg_group</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>groname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
+ </para>
+ <para>
+ Name of the group
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>grosysid</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ ID of this group
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>grolist</structfield> <type>oid[]</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ An array containing the IDs of the roles in this group
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ </sect1>
+
+ <sect1 id="view-pg-hba-file-rules">
+ <title><structname>pg_hba_file_rules</structname></title>
+
+ <indexterm zone="view-pg-hba-file-rules">
+ <primary>pg_hba_file_rules</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_hba_file_rules</structname> provides a summary of
+ the contents of the client authentication configuration file,
+ <link linkend="auth-pg-hba-conf"><filename>pg_hba.conf</filename></link>.
+ A row appears in this view for each
+ non-empty, non-comment line in the file, with annotations indicating
+ whether the rule could be applied successfully.
+ </para>
+
+ <para>
+ This view can be helpful for checking whether planned changes in the
+ authentication configuration file will work, or for diagnosing a previous
+ failure. Note that this view reports on the <emphasis>current</emphasis> contents
+ of the file, not on what was last loaded by the server.
+ </para>
+
+ <para>
+ By default, the <structname>pg_hba_file_rules</structname> view can be read
+ only by superusers.
+ </para>
+
+ <table>
+ <title><structname>pg_hba_file_rules</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>line_number</structfield> <type>int4</type>
+ </para>
+ <para>
+ Line number of this rule in <filename>pg_hba.conf</filename>
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>type</structfield> <type>text</type>
+ </para>
+ <para>
+ Type of connection
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>database</structfield> <type>text[]</type>
+ </para>
+ <para>
+ List of database name(s) to which this rule applies
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>user_name</structfield> <type>text[]</type>
+ </para>
+ <para>
+ List of user and group name(s) to which this rule applies
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>address</structfield> <type>text</type>
+ </para>
+ <para>
+ Host name or IP address, or one
+ of <literal>all</literal>, <literal>samehost</literal>,
+ or <literal>samenet</literal>, or null for local connections
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>netmask</structfield> <type>text</type>
+ </para>
+ <para>
+ IP address mask, or null if not applicable
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>auth_method</structfield> <type>text</type>
+ </para>
+ <para>
+ Authentication method
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>options</structfield> <type>text[]</type>
+ </para>
+ <para>
+ Options specified for authentication method, if any
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>error</structfield> <type>text</type>
+ </para>
+ <para>
+ If not null, an error message indicating why this
+ line could not be processed
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ Usually, a row reflecting an incorrect entry will have values for only
+ the <structfield>line_number</structfield> and <structfield>error</structfield> fields.
+ </para>
+
+ <para>
+ See <xref linkend="client-authentication"/> for more information about
+ client authentication configuration.
+ </para>
+ </sect1>
+
+ <sect1 id="view-pg-ident-file-mappings">
+ <title><structname>pg_ident_file_mappings</structname></title>
+
+ <indexterm zone="view-pg-ident-file-mappings">
+ <primary>pg_ident_file_mappings</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_ident_file_mappings</structname> provides a summary
+ of the contents of the client user name mapping configuration file,
+ <link linkend="auth-username-maps"><filename>pg_ident.conf</filename></link>.
+ A row appears in this view for each non-empty, non-comment line in the file,
+ with annotations indicating whether the rule could be applied successfully.
+ </para>
+
+ <para>
+ This view can be helpful for checking whether planned changes in the
+ authentication configuration file will work, or for diagnosing a previous
+ failure. Note that this view reports on the <emphasis>current</emphasis>
+ contents of the file, not on what was last loaded by the server.
+ </para>
+
+ <para>
+ By default, the <structname>pg_ident_file_mappings</structname> view can be
+ read only by superusers.
+ </para>
+
+ <table>
+ <title><structname>pg_ident_file_mappings</structname> Columns</title> <tgroup
+ cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>line_number</structfield> <type>int4</type>
+ </para>
+ <para>
+ Line number of this rule in <filename>pg_ident.conf</filename>
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>map_name</structfield> <type>text</type>
+ </para>
+ <para>
+ Name of the map
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>sys_name</structfield> <type>text</type>
+ </para>
+ <para>
+ Detected user name of the client
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>pg_username</structfield> <type>text</type>
+ </para>
+ <para>
+ Requested PostgreSQL user name
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>error</structfield> <type>text</type>
+ </para>
+ <para>
+ If not <literal>NULL</literal>, an error message indicating why this
+ line could not be processed
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ Usually, a row reflecting an incorrect entry will have values for only
+ the <structfield>line_number</structfield> and <structfield>error</structfield> fields.
+ </para>
+
+ <para>
+ See <xref linkend="client-authentication"/> for more information about
+ client authentication configuration.
+ </para>
+ </sect1>
+
+ <sect1 id="view-pg-indexes">
+ <title><structname>pg_indexes</structname></title>
+
+ <indexterm zone="view-pg-indexes">
+ <primary>pg_indexes</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_indexes</structname> provides access to
+ useful information about each index in the database.
+ </para>
+
+ <table>
+ <title><structname>pg_indexes</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing table and index
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>tablename</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
+ </para>
+ <para>
+ Name of table the index is for
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>indexname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
+ </para>
+ <para>
+ Name of index
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>tablespace</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-tablespace"><structname>pg_tablespace</structname></link>.<structfield>spcname</structfield>)
+ </para>
+ <para>
+ Name of tablespace containing index (null if default for database)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>indexdef</structfield> <type>text</type>
+ </para>
+ <para>
+ Index definition (a reconstructed <xref linkend="sql-createindex"/>
+ command)
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ </sect1>
+
+ <sect1 id="view-pg-locks">
+ <title><structname>pg_locks</structname></title>
+
+ <indexterm zone="view-pg-locks">
+ <primary>pg_locks</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_locks</structname> provides access to
+ information about the locks held by active processes within the
+ database server. See <xref linkend="mvcc"/> for more discussion
+ of locking.
+ </para>
+
+ <para>
+ <structname>pg_locks</structname> contains one row per active lockable
+ object, requested lock mode, and relevant process. Thus, the same
+ lockable object might
+ appear many times, if multiple processes are holding or waiting
+ for locks on it. However, an object that currently has no locks on it
+ will not appear at all.
+ </para>
+
+ <para>
+ There are several distinct types of lockable objects:
+ whole relations (e.g., tables), individual pages of relations,
+ individual tuples of relations,
+ transaction IDs (both virtual and permanent IDs),
+ and general database objects (identified by class OID and object OID,
+ in the same way as in <link linkend="catalog-pg-description"><structname>pg_description</structname></link> or
+ <link linkend="catalog-pg-depend"><structname>pg_depend</structname></link>). Also, the right to extend a
+ relation is represented as a separate lockable object, as is the right to
+ update <structname>pg_database</structname>.<structfield>datfrozenxid</structfield>.
+ Also, <quote>advisory</quote> locks can be taken on numbers that have
+ user-defined meanings.
+ </para>
+
+ <table>
+ <title><structname>pg_locks</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>locktype</structfield> <type>text</type>
+ </para>
+ <para>
+ Type of the lockable object:
+ <literal>relation</literal>,
+ <literal>extend</literal>,
+ <literal>frozenid</literal>,
+ <literal>page</literal>,
+ <literal>tuple</literal>,
+ <literal>transactionid</literal>,
+ <literal>virtualxid</literal>,
+ <literal>spectoken</literal>,
+ <literal>object</literal>,
+ <literal>userlock</literal>, or
+ <literal>advisory</literal>.
+ (See also <xref linkend="wait-event-lock-table"/>.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>database</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-database"><structname>pg_database</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ OID of the database in which the lock target exists, or
+ zero if the target is a shared object, or
+ null if the target is a transaction ID
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>relation</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ OID of the relation targeted by the lock, or null if the target is not
+ a relation or part of a relation
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>page</structfield> <type>int4</type>
+ </para>
+ <para>
+ Page number targeted by the lock within the relation,
+ or null if the target is not a relation page or tuple
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>tuple</structfield> <type>int2</type>
+ </para>
+ <para>
+ Tuple number targeted by the lock within the page,
+ or null if the target is not a tuple
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>virtualxid</structfield> <type>text</type>
+ </para>
+ <para>
+ Virtual ID of the transaction targeted by the lock,
+ or null if the target is not a virtual transaction ID
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>transactionid</structfield> <type>xid</type>
+ </para>
+ <para>
+ ID of the transaction targeted by the lock,
+ or null if the target is not a transaction ID
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>classid</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ OID of the system catalog containing the lock target, or null if the
+ target is not a general database object
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>objid</structfield> <type>oid</type>
+ (references any OID column)
+ </para>
+ <para>
+ OID of the lock target within its system catalog, or null if the
+ target is not a general database object
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>objsubid</structfield> <type>int2</type>
+ </para>
+ <para>
+ Column number targeted by the lock (the
+ <structfield>classid</structfield> and <structfield>objid</structfield> refer to the
+ table itself),
+ or zero if the target is some other general database object,
+ or null if the target is not a general database object
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>virtualtransaction</structfield> <type>text</type>
+ </para>
+ <para>
+ Virtual ID of the transaction that is holding or awaiting this lock
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>pid</structfield> <type>int4</type>
+ </para>
+ <para>
+ Process ID of the server process holding or awaiting this
+ lock, or null if the lock is held by a prepared transaction
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>mode</structfield> <type>text</type>
+ </para>
+ <para>
+ Name of the lock mode held or desired by this process (see <xref linkend="locking-tables"/> and <xref linkend="xact-serializable"/>)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>granted</structfield> <type>bool</type>
+ </para>
+ <para>
+ True if lock is held, false if lock is awaited
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>fastpath</structfield> <type>bool</type>
+ </para>
+ <para>
+ True if lock was taken via fast path, false if taken via main
+ lock table
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>waitstart</structfield> <type>timestamptz</type>
+ </para>
+ <para>
+ Time when the server process started waiting for this lock,
+ or null if the lock is held.
+ Note that this can be null for a very short period of time after
+ the wait started even though <structfield>granted</structfield>
+ is <literal>false</literal>.
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ <structfield>granted</structfield> is true in a row representing a lock
+ held by the indicated process. False indicates that this process is
+ currently waiting to acquire this lock, which implies that at least one
+ other process is holding or waiting for a conflicting lock mode on the same
+ lockable object. The waiting process will sleep until the other lock is
+ released (or a deadlock situation is detected). A single process can be
+ waiting to acquire at most one lock at a time.
+ </para>
+
+ <para>
+ Throughout running a transaction, a server process holds an exclusive lock
+ on the transaction's virtual transaction ID. If a permanent ID is assigned
+ to the transaction (which normally happens only if the transaction changes
+ the state of the database), it also holds an exclusive lock on the
+ transaction's permanent transaction ID until it ends. When a process finds
+ it necessary to wait specifically for another transaction to end, it does
+ so by attempting to acquire share lock on the other transaction's ID
+ (either virtual or permanent ID depending on the situation). That will
+ succeed only when the other transaction terminates and releases its locks.
+ </para>
+
+ <para>
+ Although tuples are a lockable type of object,
+ information about row-level locks is stored on disk, not in memory,
+ and therefore row-level locks normally do not appear in this view.
+ If a process is waiting for a
+ row-level lock, it will usually appear in the view as waiting for the
+ permanent transaction ID of the current holder of that row lock.
+ </para>
+
+ <para>
+ Advisory locks can be acquired on keys consisting of either a single
+ <type>bigint</type> value or two integer values.
+ A <type>bigint</type> key is displayed with its
+ high-order half in the <structfield>classid</structfield> column, its low-order half
+ in the <structfield>objid</structfield> column, and <structfield>objsubid</structfield> equal
+ to 1. The original <type>bigint</type> value can be reassembled with the
+ expression <literal>(classid::bigint << 32) |
+ objid::bigint</literal>. Integer keys are displayed with the
+ first key in the
+ <structfield>classid</structfield> column, the second key in the <structfield>objid</structfield>
+ column, and <structfield>objsubid</structfield> equal to 2. The actual meaning of
+ the keys is up to the user. Advisory locks are local to each database,
+ so the <structfield>database</structfield> column is meaningful for an advisory lock.
+ </para>
+
+ <para>
+ <structname>pg_locks</structname> provides a global view of all locks
+ in the database cluster, not only those relevant to the current database.
+ Although its <structfield>relation</structfield> column can be joined
+ against <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield> to identify locked
+ relations, this will only work correctly for relations in the current
+ database (those for which the <structfield>database</structfield> column
+ is either the current database's OID or zero).
+ </para>
+
+ <para>
+ The <structfield>pid</structfield> column can be joined to the
+ <structfield>pid</structfield> column of the
+ <link linkend="monitoring-pg-stat-activity-view">
+ <structname>pg_stat_activity</structname></link>
+ view to get more
+ information on the session holding or awaiting each lock,
+ for example
+<programlisting>
+SELECT * FROM pg_locks pl LEFT JOIN pg_stat_activity psa
+ ON pl.pid = psa.pid;
+</programlisting>
+ Also, if you are using prepared transactions, the
+ <structfield>virtualtransaction</structfield> column can be joined to the
+ <structfield>transaction</structfield> column of the <link
+ linkend="view-pg-prepared-xacts"><structname>pg_prepared_xacts</structname></link>
+ view to get more information on prepared transactions that hold locks.
+ (A prepared transaction can never be waiting for a lock,
+ but it continues to hold the locks it acquired while running.)
+ For example:
+<programlisting>
+SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
+ ON pl.virtualtransaction = '-1/' || ppx.transaction;
+</programlisting>
+ </para>
+
+ <para>
+ While it is possible to obtain information about which processes block
+ which other processes by joining <structname>pg_locks</structname> against
+ itself, this is very difficult to get right in detail. Such a query would
+ have to encode knowledge about which lock modes conflict with which
+ others. Worse, the <structname>pg_locks</structname> view does not expose
+ information about which processes are ahead of which others in lock wait
+ queues, nor information about which processes are parallel workers running
+ on behalf of which other client sessions. It is better to use
+ the <function>pg_blocking_pids()</function> function
+ (see <xref linkend="functions-info-session-table"/>) to identify which
+ process(es) a waiting process is blocked behind.
+ </para>
+
+ <para>
+ The <structname>pg_locks</structname> view displays data from both the
+ regular lock manager and the predicate lock manager, which are
+ separate systems; in addition, the regular lock manager subdivides its
+ locks into regular and <firstterm>fast-path</firstterm> locks.
+ This data is not guaranteed to be entirely consistent.
+ When the view is queried,
+ data on fast-path locks (with <structfield>fastpath</structfield> = <literal>true</literal>)
+ is gathered from each backend one at a time, without freezing the state of
+ the entire lock manager, so it is possible for locks to be taken or
+ released while information is gathered. Note, however, that these locks are
+ known not to conflict with any other lock currently in place. After
+ all backends have been queried for fast-path locks, the remainder of the
+ regular lock manager is locked as a unit, and a consistent snapshot of all
+ remaining locks is collected as an atomic action. After unlocking the
+ regular lock manager, the predicate lock manager is similarly locked and all
+ predicate locks are collected as an atomic action. Thus, with the exception
+ of fast-path locks, each lock manager will deliver a consistent set of
+ results, but as we do not lock both lock managers simultaneously, it is
+ possible for locks to be taken or released after we interrogate the regular
+ lock manager and before we interrogate the predicate lock manager.
+ </para>
+
+ <para>
+ Locking the regular and/or predicate lock manager could have some
+ impact on database performance if this view is very frequently accessed.
+ The locks are held only for the minimum amount of time necessary to
+ obtain data from the lock managers, but this does not completely eliminate
+ the possibility of a performance impact.
+ </para>
+
+ </sect1>
+
+ <sect1 id="view-pg-matviews">
+ <title><structname>pg_matviews</structname></title>
+
+ <indexterm zone="view-pg-matviews">
+ <primary>pg_matviews</primary>
+ </indexterm>
+
+ <indexterm zone="view-pg-matviews">
+ <primary>materialized views</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_matviews</structname> provides access to
+ useful information about each materialized view in the database.
+ </para>
+
+ <table>
+ <title><structname>pg_matviews</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing materialized view
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>matviewname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
+ </para>
+ <para>
+ Name of materialized view
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>matviewowner</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
+ </para>
+ <para>
+ Name of materialized view's owner
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>tablespace</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-tablespace"><structname>pg_tablespace</structname></link>.<structfield>spcname</structfield>)
+ </para>
+ <para>
+ Name of tablespace containing materialized view (null if default for database)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>hasindexes</structfield> <type>bool</type>
+ </para>
+ <para>
+ True if materialized view has (or recently had) any indexes
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>ispopulated</structfield> <type>bool</type>
+ </para>
+ <para>
+ True if materialized view is currently populated
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>definition</structfield> <type>text</type>
+ </para>
+ <para>
+ Materialized view definition (a reconstructed <xref linkend="sql-select"/> query)
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ </sect1>
+
+ <sect1 id="view-pg-policies">
+ <title><structname>pg_policies</structname></title>
+
+ <indexterm zone="view-pg-policies">
+ <primary>pg_policies</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_policies</structname> provides access to
+ useful information about each row-level security policy in the database.
+ </para>
+
+ <table>
+ <title><structname>pg_policies</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing table policy is on
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>tablename</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
+ </para>
+ <para>
+ Name of table policy is on
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>policyname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-policy"><structname>pg_policy</structname></link>.<structfield>polname</structfield>)
+ </para>
+ <para>
+ Name of policy
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>permissive</structfield> <type>text</type>
+ </para>
+ <para>
+ Is the policy permissive or restrictive?
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>roles</structfield> <type>name[]</type>
+ </para>
+ <para>
+ The roles to which this policy applies
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>cmd</structfield> <type>text</type>
+ </para>
+ <para>
+ The command type to which the policy is applied
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>qual</structfield> <type>text</type>
+ </para>
+ <para>
+ The expression added to the security barrier qualifications for
+ queries that this policy applies to
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>with_check</structfield> <type>text</type>
+ </para>
+ <para>
+ The expression added to the WITH CHECK qualifications for
+ queries that attempt to add rows to this table
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ </sect1>
+
+ <sect1 id="view-pg-prepared-statements">
+ <title><structname>pg_prepared_statements</structname></title>
+
+ <indexterm zone="view-pg-prepared-statements">
+ <primary>pg_prepared_statements</primary>
+ </indexterm>
+
+ <para>
+ The <structname>pg_prepared_statements</structname> view displays
+ all the prepared statements that are available in the current
+ session. See <xref linkend="sql-prepare"/> for more information about prepared
+ statements.
+ </para>
+
+ <para>
+ <structname>pg_prepared_statements</structname> contains one row
+ for each prepared statement. Rows are added to the view when a new
+ prepared statement is created and removed when a prepared statement
+ is released (for example, via the <link linkend="sql-deallocate"><command>DEALLOCATE</command></link> command).
+ </para>
+
+ <table>
+ <title><structname>pg_prepared_statements</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>name</structfield> <type>text</type>
+ </para>
+ <para>
+ The identifier of the prepared statement
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>statement</structfield> <type>text</type>
+ </para>
+ <para>
+ The query string submitted by the client to create this
+ prepared statement. For prepared statements created via SQL,
+ this is the <command>PREPARE</command> statement submitted by
+ the client. For prepared statements created via the
+ frontend/backend protocol, this is the text of the prepared
+ statement itself.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>prepare_time</structfield> <type>timestamptz</type>
+ </para>
+ <para>
+ The time at which the prepared statement was created
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>parameter_types</structfield> <type>regtype[]</type>
+ </para>
+ <para>
+ The expected parameter types for the prepared statement in the
+ form of an array of <type>regtype</type>. The OID corresponding
+ to an element of this array can be obtained by casting the
+ <type>regtype</type> value to <type>oid</type>.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>result_types</structfield> <type>regtype[]</type>
+ </para>
+ <para>
+ The types of the columns returned by the prepared statement in the
+ form of an array of <type>regtype</type>. The OID corresponding
+ to an element of this array can be obtained by casting the
+ <type>regtype</type> value to <type>oid</type>.
+ If the prepared statement does not provide a result (e.g., a DML
+ statement), then this field will be null.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>from_sql</structfield> <type>bool</type>
+ </para>
+ <para>
+ <literal>true</literal> if the prepared statement was created
+ via the <command>PREPARE</command> SQL command;
+ <literal>false</literal> if the statement was prepared via the
+ frontend/backend protocol
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>generic_plans</structfield> <type>int8</type>
+ </para>
+ <para>
+ Number of times generic plan was chosen
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>custom_plans</structfield> <type>int8</type>
+ </para>
+ <para>
+ Number of times custom plan was chosen
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ The <structname>pg_prepared_statements</structname> view is read-only.
+ </para>
+ </sect1>
+
+ <sect1 id="view-pg-prepared-xacts">
+ <title><structname>pg_prepared_xacts</structname></title>
+
+ <indexterm zone="view-pg-prepared-xacts">
+ <primary>pg_prepared_xacts</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_prepared_xacts</structname> displays
+ information about transactions that are currently prepared for two-phase
+ commit (see <xref linkend="sql-prepare-transaction"/> for details).
+ </para>
+
+ <para>
+ <structname>pg_prepared_xacts</structname> contains one row per prepared
+ transaction. An entry is removed when the transaction is committed or
+ rolled back.
+ </para>
+
+ <table>
+ <title><structname>pg_prepared_xacts</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>transaction</structfield> <type>xid</type>
+ </para>
+ <para>
+ Numeric transaction identifier of the prepared transaction
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>gid</structfield> <type>text</type>
+ </para>
+ <para>
+ Global transaction identifier that was assigned to the transaction
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>prepared</structfield> <type>timestamptz</type>
+ </para>
+ <para>
+ Time at which the transaction was prepared for commit
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>owner</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
+ </para>
+ <para>
+ Name of the user that executed the transaction
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>database</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-database"><structname>pg_database</structname></link>.<structfield>datname</structfield>)
+ </para>
+ <para>
+ Name of the database in which the transaction was executed
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ When the <structname>pg_prepared_xacts</structname> view is accessed, the
+ internal transaction manager data structures are momentarily locked, and
+ a copy is made for the view to display. This ensures that the
+ view produces a consistent set of results, while not blocking
+ normal operations longer than necessary. Nonetheless
+ there could be some impact on database performance if this view is
+ frequently accessed.
+ </para>
+
+ </sect1>
+
+ <sect1 id="view-pg-publication-tables">
+ <title><structname>pg_publication_tables</structname></title>
+
+ <indexterm zone="view-pg-publication-tables">
+ <primary>pg_publication_tables</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_publication_tables</structname> provides
+ information about the mapping between publications and information of
+ tables they contain. Unlike the underlying catalog
+ <link linkend="catalog-pg-publication-rel"><structname>pg_publication_rel</structname></link>,
+ this view expands publications defined as <literal>FOR ALL TABLES</literal>
+ and <literal>FOR ALL TABLES IN SCHEMA</literal>, so for such publications
+ there will be a row for each eligible table.
+ </para>
+
+ <table>
+ <title><structname>pg_publication_tables</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>pubname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-publication"><structname>pg_publication</structname></link>.<structfield>pubname</structfield>)
+ </para>
+ <para>
+ Name of publication
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing table
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>tablename</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
+ </para>
+ <para>
+ Name of table
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>attnames</structfield> <type>name[]</type>
+ (references <link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>.<structfield>attname</structfield>)
+ </para>
+ <para>
+ Names of table columns included in the publication. This contains all
+ the columns of the table when the user didn't specify the column list
+ for the table.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>rowfilter</structfield> <type>text</type>
+ </para>
+ <para>
+ Expression for the table's publication qualifying condition
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </sect1>
+
+ <sect1 id="view-pg-replication-origin-status">
+ <title><structname>pg_replication_origin_status</structname></title>
+
+ <indexterm zone="view-pg-replication-origin-status">
+ <primary>pg_replication_origin_status</primary>
+ </indexterm>
+
+ <para>
+ The <structname>pg_replication_origin_status</structname> view
+ contains information about how far replay for a certain origin has
+ progressed. For more on replication origins
+ see <xref linkend="replication-origins"/>.
+ </para>
+
+ <table>
+ <title><structname>pg_replication_origin_status</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>local_id</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-replication-origin"><structname>pg_replication_origin</structname></link>.<structfield>roident</structfield>)
+ </para>
+ <para>
+ internal node identifier
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>external_id</structfield> <type>text</type>
+ (references <link linkend="catalog-pg-replication-origin"><structname>pg_replication_origin</structname></link>.<structfield>roname</structfield>)
+ </para>
+ <para>
+ external node identifier
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>remote_lsn</structfield> <type>pg_lsn</type>
+ </para>
+ <para>
+ The origin node's LSN up to which data has been replicated.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>local_lsn</structfield> <type>pg_lsn</type>
+ </para>
+ <para>
+ This node's LSN at which <literal>remote_lsn</literal> has
+ been replicated. Used to flush commit records before persisting
+ data to disk when using asynchronous commits.
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </sect1>
+
+ <sect1 id="view-pg-replication-slots">
+ <title><structname>pg_replication_slots</structname></title>
+
+ <indexterm zone="view-pg-replication-slots">
+ <primary>pg_replication_slots</primary>
+ </indexterm>
+
+ <para>
+ The <structname>pg_replication_slots</structname> view provides a listing
+ of all replication slots that currently exist on the database cluster,
+ along with their current state.
+ </para>
+
+ <para>
+ For more on replication slots,
+ see <xref linkend="streaming-replication-slots"/> and <xref linkend="logicaldecoding"/>.
+ </para>
+
+ <table>
+ <title><structname>pg_replication_slots</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>slot_name</structfield> <type>name</type>
+ </para>
+ <para>
+ A unique, cluster-wide identifier for the replication slot
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>plugin</structfield> <type>name</type>
+ </para>
+ <para>
+ The base name of the shared object containing the output plugin this logical slot is using, or null for physical slots.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>slot_type</structfield> <type>text</type>
+ </para>
+ <para>
+ The slot type: <literal>physical</literal> or <literal>logical</literal>
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>datoid</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-database"><structname>pg_database</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ The OID of the database this slot is associated with, or
+ null. Only logical slots have an associated database.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>database</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-database"><structname>pg_database</structname></link>.<structfield>datname</structfield>)
+ </para>
+ <para>
+ The name of the database this slot is associated with, or
+ null. Only logical slots have an associated database.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>temporary</structfield> <type>bool</type>
+ </para>
+ <para>
+ True if this is a temporary replication slot. Temporary slots are
+ not saved to disk and are automatically dropped on error or when
+ the session has finished.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>active</structfield> <type>bool</type>
+ </para>
+ <para>
+ True if this slot is currently actively being used
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>active_pid</structfield> <type>int4</type>
+ </para>
+ <para>
+ The process ID of the session using this slot if the slot
+ is currently actively being used. <literal>NULL</literal> if
+ inactive.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>xmin</structfield> <type>xid</type>
+ </para>
+ <para>
+ The oldest transaction that this slot needs the database to
+ retain. <literal>VACUUM</literal> cannot remove tuples deleted
+ by any later transaction.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>catalog_xmin</structfield> <type>xid</type>
+ </para>
+ <para>
+ The oldest transaction affecting the system catalogs that this
+ slot needs the database to retain. <literal>VACUUM</literal> cannot
+ remove catalog tuples deleted by any later transaction.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>restart_lsn</structfield> <type>pg_lsn</type>
+ </para>
+ <para>
+ The address (<literal>LSN</literal>) of oldest WAL which still
+ might be required by the consumer of this slot and thus won't be
+ automatically removed during checkpoints unless this LSN
+ gets behind more than <xref linkend="guc-max-slot-wal-keep-size"/>
+ from the current LSN. <literal>NULL</literal>
+ if the <literal>LSN</literal> of this slot has never been reserved.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>confirmed_flush_lsn</structfield> <type>pg_lsn</type>
+ </para>
+ <para>
+ The address (<literal>LSN</literal>) up to which the logical
+ slot's consumer has confirmed receiving data. Data older than this is
+ not available anymore. <literal>NULL</literal> for physical slots.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>wal_status</structfield> <type>text</type>
+ </para>
+ <para>
+ Availability of WAL files claimed by this slot.
+ Possible values are:
+ <itemizedlist>
+ <listitem>
+ <para><literal>reserved</literal> means that the claimed files
+ are within <varname>max_wal_size</varname>.</para>
+ </listitem>
+ <listitem>
+ <para><literal>extended</literal> means
+ that <varname>max_wal_size</varname> is exceeded but the files are
+ still retained, either by the replication slot or
+ by <varname>wal_keep_size</varname>.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <literal>unreserved</literal> means that the slot no longer
+ retains the required WAL files and some of them are to be removed at
+ the next checkpoint. This state can return
+ to <literal>reserved</literal> or <literal>extended</literal>.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <literal>lost</literal> means that some required WAL files have
+ been removed and this slot is no longer usable.
+ </para>
+ </listitem>
+ </itemizedlist>
+ The last two states are seen only when
+ <xref linkend="guc-max-slot-wal-keep-size"/> is
+ non-negative. If <structfield>restart_lsn</structfield> is NULL, this
+ field is null.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>safe_wal_size</structfield> <type>int8</type>
+ </para>
+ <para>
+ The number of bytes that can be written to WAL such that this slot
+ is not in danger of getting in state "lost". It is NULL for lost
+ slots, as well as if <varname>max_slot_wal_keep_size</varname>
+ is <literal>-1</literal>.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>two_phase</structfield> <type>bool</type>
+ </para>
+ <para>
+ True if the slot is enabled for decoding prepared transactions. Always
+ false for physical slots.
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </sect1>
+
+ <sect1 id="view-pg-roles">
+ <title><structname>pg_roles</structname></title>
+
+ <indexterm zone="view-pg-roles">
+ <primary>pg_roles</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_roles</structname> provides access to
+ information about database roles. This is simply a publicly
+ readable view of
+ <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>
+ that blanks out the password field.
+ </para>
+
+ <table>
+ <title><structname>pg_roles</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>rolname</structfield> <type>name</type>
+ </para>
+ <para>
+ Role name
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>rolsuper</structfield> <type>bool</type>
+ </para>
+ <para>
+ Role has superuser privileges
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>rolinherit</structfield> <type>bool</type>
+ </para>
+ <para>
+ Role automatically inherits privileges of roles it is a
+ member of
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>rolcreaterole</structfield> <type>bool</type>
+ </para>
+ <para>
+ Role can create more roles
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>rolcreatedb</structfield> <type>bool</type>
+ </para>
+ <para>
+ Role can create databases
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>rolcanlogin</structfield> <type>bool</type>
+ </para>
+ <para>
+ Role can log in. That is, this role can be given as the initial
+ session authorization identifier
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>rolreplication</structfield> <type>bool</type>
+ </para>
+ <para>
+ Role is a replication role. A replication role can initiate replication
+ connections and create and drop replication slots.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>rolconnlimit</structfield> <type>int4</type>
+ </para>
+ <para>
+ For roles that can log in, this sets maximum number of concurrent
+ connections this role can make. -1 means no limit.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>rolpassword</structfield> <type>text</type>
+ </para>
+ <para>
+ Not the password (always reads as <literal>********</literal>)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>rolvaliduntil</structfield> <type>timestamptz</type>
+ </para>
+ <para>
+ Password expiry time (only used for password authentication);
+ null if no expiration
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>rolbypassrls</structfield> <type>bool</type>
+ </para>
+ <para>
+ Role bypasses every row-level security policy, see
+ <xref linkend="ddl-rowsecurity"/> for more information.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>rolconfig</structfield> <type>text[]</type>
+ </para>
+ <para>
+ Role-specific defaults for run-time configuration variables
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>oid</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ ID of role
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ </sect1>
+
+ <sect1 id="view-pg-rules">
+ <title><structname>pg_rules</structname></title>
+
+ <indexterm zone="view-pg-rules">
+ <primary>pg_rules</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_rules</structname> provides access to
+ useful information about query rewrite rules.
+ </para>
+
+ <table>
+ <title><structname>pg_rules</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing table
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>tablename</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
+ </para>
+ <para>
+ Name of table the rule is for
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>rulename</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-rewrite"><structname>pg_rewrite</structname></link>.<structfield>rulename</structfield>)
+ </para>
+ <para>
+ Name of rule
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>definition</structfield> <type>text</type>
+ </para>
+ <para>
+ Rule definition (a reconstructed creation command)
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ The <structname>pg_rules</structname> view excludes the <literal>ON SELECT</literal> rules
+ of views and materialized views; those can be seen in
+ <link linkend="view-pg-views"><structname>pg_views</structname></link> and <link linkend="view-pg-matviews"><structname>pg_matviews</structname></link>.
+ </para>
+
+ </sect1>
+
+ <sect1 id="view-pg-seclabels">
+ <title><structname>pg_seclabels</structname></title>
+
+ <indexterm zone="view-pg-seclabels">
+ <primary>pg_seclabels</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_seclabels</structname> provides information about
+ security labels. It as an easier-to-query version of the
+ <link linkend="catalog-pg-seclabel"><structname>pg_seclabel</structname></link> catalog.
+ </para>
+
+ <table>
+ <title><structname>pg_seclabels</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>objoid</structfield> <type>oid</type>
+ (references any OID column)
+ </para>
+ <para>
+ The OID of the object this security label pertains to
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>classoid</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ The OID of the system catalog this object appears in
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>objsubid</structfield> <type>int4</type>
+ </para>
+ <para>
+ For a security label on a table column, this is the column number (the
+ <structfield>objoid</structfield> and <structfield>classoid</structfield> refer to
+ the table itself). For all other object types, this column is
+ zero.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>objtype</structfield> <type>text</type>
+ </para>
+ <para>
+ The type of object to which this label applies, as text.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>objnamespace</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ The OID of the namespace for this object, if applicable;
+ otherwise NULL.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>objname</structfield> <type>text</type>
+ </para>
+ <para>
+ The name of the object to which this label applies, as text.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>provider</structfield> <type>text</type>
+ (references <link linkend="catalog-pg-seclabel"><structname>pg_seclabel</structname></link>.<structfield>provider</structfield>)
+ </para>
+ <para>
+ The label provider associated with this label.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>label</structfield> <type>text</type>
+ (references <link linkend="catalog-pg-seclabel"><structname>pg_seclabel</structname></link>.<structfield>label</structfield>)
+ </para>
+ <para>
+ The security label applied to this object.
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </sect1>
+
+ <sect1 id="view-pg-sequences">
+ <title><structname>pg_sequences</structname></title>
+
+ <indexterm zone="view-pg-sequences">
+ <primary>pg_sequences</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_sequences</structname> provides access to
+ useful information about each sequence in the database.
+ </para>
+
+ <table>
+ <title><structname>pg_sequences</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing sequence
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>sequencename</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
+ </para>
+ <para>
+ Name of sequence
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>sequenceowner</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
+ </para>
+ <para>
+ Name of sequence's owner
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>data_type</structfield> <type>regtype</type>
+ (references <link linkend="catalog-pg-type"><structname>pg_type</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ Data type of the sequence
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>start_value</structfield> <type>int8</type>
+ </para>
+ <para>
+ Start value of the sequence
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>min_value</structfield> <type>int8</type>
+ </para>
+ <para>
+ Minimum value of the sequence
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>max_value</structfield> <type>int8</type>
+ </para>
+ <para>
+ Maximum value of the sequence
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>increment_by</structfield> <type>int8</type>
+ </para>
+ <para>
+ Increment value of the sequence
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>cycle</structfield> <type>bool</type>
+ </para>
+ <para>
+ Whether the sequence cycles
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>cache_size</structfield> <type>int8</type>
+ </para>
+ <para>
+ Cache size of the sequence
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>last_value</structfield> <type>int8</type>
+ </para>
+ <para>
+ The last sequence value written to disk. If caching is used,
+ this value can be greater than the last value handed out from the
+ sequence. Null if the sequence has not been read from yet. Also, if
+ the current user does not have <literal>USAGE</literal>
+ or <literal>SELECT</literal> privilege on the sequence, the value is
+ null.
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </sect1>
+
+ <sect1 id="view-pg-settings">
+ <title><structname>pg_settings</structname></title>
+
+ <indexterm zone="view-pg-settings">
+ <primary>pg_settings</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_settings</structname> provides access to
+ run-time parameters of the server. It is essentially an alternative
+ interface to the <link linkend="sql-show"><command>SHOW</command></link>
+ and <link linkend="sql-set"><command>SET</command></link> commands.
+ It also provides access to some facts about each parameter that are
+ not directly available from <link linkend="sql-show"><command>SHOW</command></link>, such as minimum and
+ maximum values.
+ </para>
+
+ <table>
+ <title><structname>pg_settings</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>name</structfield> <type>text</type>
+ </para>
+ <para>
+ Run-time configuration parameter name
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>setting</structfield> <type>text</type>
+ </para>
+ <para>
+ Current value of the parameter
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>unit</structfield> <type>text</type>
+ </para>
+ <para>
+ Implicit unit of the parameter
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>category</structfield> <type>text</type>
+ </para>
+ <para>
+ Logical group of the parameter
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>short_desc</structfield> <type>text</type>
+ </para>
+ <para>
+ A brief description of the parameter
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>extra_desc</structfield> <type>text</type>
+ </para>
+ <para>
+ Additional, more detailed, description of the parameter
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>context</structfield> <type>text</type>
+ </para>
+ <para>
+ Context required to set the parameter's value (see below)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>vartype</structfield> <type>text</type>
+ </para>
+ <para>
+ Parameter type (<literal>bool</literal>, <literal>enum</literal>,
+ <literal>integer</literal>, <literal>real</literal>, or <literal>string</literal>)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>source</structfield> <type>text</type>
+ </para>
+ <para>
+ Source of the current parameter value
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>min_val</structfield> <type>text</type>
+ </para>
+ <para>
+ Minimum allowed value of the parameter (null for non-numeric
+ values)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>max_val</structfield> <type>text</type>
+ </para>
+ <para>
+ Maximum allowed value of the parameter (null for non-numeric
+ values)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>enumvals</structfield> <type>text[]</type>
+ </para>
+ <para>
+ Allowed values of an enum parameter (null for non-enum
+ values)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>boot_val</structfield> <type>text</type>
+ </para>
+ <para>
+ Parameter value assumed at server startup if the parameter is
+ not otherwise set
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>reset_val</structfield> <type>text</type>
+ </para>
+ <para>
+ Value that <link linkend="sql-reset"><command>RESET</command></link> would reset the parameter to
+ in the current session
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>sourcefile</structfield> <type>text</type>
+ </para>
+ <para>
+ Configuration file the current value was set in (null for
+ values set from sources other than configuration files, or when
+ examined by a user who neither is a superuser nor has privileges of
+ <literal>pg_read_all_settings</literal>); helpful when using
+ <literal>include</literal> directives in configuration files
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>sourceline</structfield> <type>int4</type>
+ </para>
+ <para>
+ Line number within the configuration file the current value was
+ set at (null for values set from sources other than configuration files,
+ or when examined by a user who neither is a superuser nor has privileges of
+ <literal>pg_read_all_settings</literal>).
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>pending_restart</structfield> <type>bool</type>
+ </para>
+ <para>
+ <literal>true</literal> if the value has been changed in the
+ configuration file but needs a restart; or <literal>false</literal>
+ otherwise.
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ There are several possible values of <structfield>context</structfield>.
+ In order of decreasing difficulty of changing the setting, they are:
+ </para>
+
+ <variablelist>
+ <varlistentry>
+ <!-- PGC_INTERNAL -->
+ <term><literal>internal</literal></term>
+ <listitem>
+ <para>
+ These settings cannot be changed directly; they reflect internally
+ determined values. Some of them may be adjustable by rebuilding the
+ server with different configuration options, or by changing options
+ supplied to <application>initdb</application>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <!-- PGC_POSTMASTER -->
+ <term><literal>postmaster</literal></term>
+ <listitem>
+ <para>
+ These settings can only be applied when the server starts, so any change
+ requires restarting the server. Values for these settings are typically
+ stored in the <filename>postgresql.conf</filename> file, or passed on
+ the command line when starting the server. Of course, settings with any
+ of the lower <structfield>context</structfield> types can also be
+ set at server start time.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <!-- PGC_SIGHUP -->
+ <term><literal>sighup</literal></term>
+ <listitem>
+ <para>
+ Changes to these settings can be made in
+ <filename>postgresql.conf</filename> without restarting the server.
+ Send a <systemitem>SIGHUP</systemitem> signal to the postmaster to
+ cause it to re-read <filename>postgresql.conf</filename> and apply
+ the changes. The postmaster will also forward the
+ <systemitem>SIGHUP</systemitem> signal to its child processes so that
+ they all pick up the new value.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <!-- PGC_SU_BACKEND -->
+ <term><literal>superuser-backend</literal></term>
+ <listitem>
+ <para>
+ Changes to these settings can be made in
+ <filename>postgresql.conf</filename> without restarting the server.
+ They can also be set for a particular session in the connection request
+ packet (for example, via <application>libpq</application>'s <literal>PGOPTIONS</literal>
+ environment variable), but only if the connecting user is a superuser
+ or has been granted the appropriate <literal>SET</literal> privilege.
+ However, these settings never change in a session after it is started.
+ If you change them in <filename>postgresql.conf</filename>, send a
+ <systemitem>SIGHUP</systemitem> signal to the postmaster to cause it to
+ re-read <filename>postgresql.conf</filename>. The new values will only
+ affect subsequently-launched sessions.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <!-- PGC_BACKEND -->
+ <term><literal>backend</literal></term>
+ <listitem>
+ <para>
+ Changes to these settings can be made in
+ <filename>postgresql.conf</filename> without restarting the server.
+ They can also be set for a particular session in the connection request
+ packet (for example, via <application>libpq</application>'s <literal>PGOPTIONS</literal>
+ environment variable); any user can make such a change for their session.
+ However, these settings never change in a session after it is started.
+ If you change them in <filename>postgresql.conf</filename>, send a
+ <systemitem>SIGHUP</systemitem> signal to the postmaster to cause it to
+ re-read <filename>postgresql.conf</filename>. The new values will only
+ affect subsequently-launched sessions.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <!-- PGC_SUSET -->
+ <term><literal>superuser</literal></term>
+ <listitem>
+ <para>
+ These settings can be set from <filename>postgresql.conf</filename>,
+ or within a session via the <command>SET</command> command; but only superusers
+ and users with the appropriate <literal>SET</literal> privilege
+ can change them via <command>SET</command>. Changes in
+ <filename>postgresql.conf</filename> will affect existing sessions
+ only if no session-local value has been established with <command>SET</command>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <!-- PGC_USERSET -->
+ <term><literal>user</literal></term>
+ <listitem>
+ <para>
+ These settings can be set from <filename>postgresql.conf</filename>,
+ or within a session via the <command>SET</command> command. Any user is
+ allowed to change their session-local value. Changes in
+ <filename>postgresql.conf</filename> will affect existing sessions
+ only if no session-local value has been established with <command>SET</command>.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+
+ <para>
+ See <xref linkend="config-setting"/> for more information about the various
+ ways to change these parameters.
+ </para>
+
+ <para>
+ This view does not display <link linkend="runtime-config-custom">customized options</link>
+ until the extension module that defines them has been loaded.
+ </para>
+
+ <para>
+ This view cannot be inserted into or deleted from, but it can be updated. An
+ <command>UPDATE</command> applied to a row of <structname>pg_settings</structname>
+ is equivalent to executing the <command>SET</command> command on that named
+ parameter. The change only affects the value used by the current
+ session. If an <command>UPDATE</command> is issued within a transaction
+ that is later aborted, the effects of the <command>UPDATE</command> command
+ disappear when the transaction is rolled back. Once the surrounding
+ transaction is committed, the effects will persist until the end of the
+ session, unless overridden by another <command>UPDATE</command> or
+ <command>SET</command>.
+ </para>
+
+ </sect1>
+
+ <sect1 id="view-pg-shadow">
+ <title><structname>pg_shadow</structname></title>
+
+ <indexterm zone="view-pg-shadow">
+ <primary>pg_shadow</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_shadow</structname> exists for backwards
+ compatibility: it emulates a catalog that existed in
+ <productname>PostgreSQL</productname> before version 8.1.
+ It shows properties of all roles that are marked as
+ <structfield>rolcanlogin</structfield> in
+ <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.
+ </para>
+
+ <para>
+ The name stems from the fact that this table
+ should not be readable by the public since it contains passwords.
+ <link linkend="view-pg-user"><structname>pg_user</structname></link>
+ is a publicly readable view on
+ <structname>pg_shadow</structname> that blanks out the password field.
+ </para>
+
+ <table>
+ <title><structname>pg_shadow</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>usename</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
+ </para>
+ <para>
+ User name
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>usesysid</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ ID of this user
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>usecreatedb</structfield> <type>bool</type>
+ </para>
+ <para>
+ User can create databases
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>usesuper</structfield> <type>bool</type>
+ </para>
+ <para>
+ User is a superuser
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>userepl</structfield> <type>bool</type>
+ </para>
+ <para>
+ User can initiate streaming replication and put the system in and
+ out of backup mode.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>usebypassrls</structfield> <type>bool</type>
+ </para>
+ <para>
+ User bypasses every row-level security policy, see
+ <xref linkend="ddl-rowsecurity"/> for more information.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>passwd</structfield> <type>text</type>
+ </para>
+ <para>
+ Password (possibly encrypted); null if none. See
+ <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>
+ for details of how encrypted passwords are stored.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>valuntil</structfield> <type>timestamptz</type>
+ </para>
+ <para>
+ Password expiry time (only used for password authentication)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>useconfig</structfield> <type>text[]</type>
+ </para>
+ <para>
+ Session defaults for run-time configuration variables
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ </sect1>
+
+ <sect1 id="view-pg-shmem-allocations">
+ <title><structname>pg_shmem_allocations</structname></title>
+
+ <indexterm zone="view-pg-shmem-allocations">
+ <primary>pg_shmem_allocations</primary>
+ </indexterm>
+
+ <para>
+ The <structname>pg_shmem_allocations</structname> view shows allocations
+ made from the server's main shared memory segment. This includes both
+ memory allocated by <productname>PostgreSQL</productname> itself and memory
+ allocated by extensions using the mechanisms detailed in
+ <xref linkend="xfunc-shared-addin" />.
+ </para>
+
+ <para>
+ Note that this view does not include memory allocated using the dynamic
+ shared memory infrastructure.
+ </para>
+
+ <table>
+ <title><structname>pg_shmem_allocations</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>name</structfield> <type>text</type>
+ </para>
+ <para>
+ The name of the shared memory allocation. NULL for unused memory
+ and <literal><anonymous></literal> for anonymous
+ allocations.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>off</structfield> <type>int8</type>
+ </para>
+ <para>
+ The offset at which the allocation starts. NULL for anonymous
+ allocations, since details related to them are not known.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>size</structfield> <type>int8</type>
+ </para>
+ <para>
+ Size of the allocation
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>allocated_size</structfield> <type>int8</type>
+ </para>
+ <para>
+ Size of the allocation including padding. For anonymous
+ allocations, no information about padding is available, so the
+ <literal>size</literal> and <literal>allocated_size</literal> columns
+ will always be equal. Padding is not meaningful for free memory, so
+ the columns will be equal in that case also.
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ Anonymous allocations are allocations that have been made
+ with <literal>ShmemAlloc()</literal> directly, rather than via
+ <literal>ShmemInitStruct()</literal> or
+ <literal>ShmemInitHash()</literal>.
+ </para>
+
+ <para>
+ By default, the <structname>pg_shmem_allocations</structname> view can be
+ read only by superusers or roles with privileges of the
+ <literal>pg_read_all_stats</literal> role.
+ </para>
+ </sect1>
+
+ <sect1 id="view-pg-stats">
+ <title><structname>pg_stats</structname></title>
+
+ <indexterm zone="view-pg-stats">
+ <primary>pg_stats</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_stats</structname> provides access to
+ the information stored in the <link
+ linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link>
+ catalog. This view allows access only to rows of
+ <link linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link> that correspond to tables the
+ user has permission to read, and therefore it is safe to allow public
+ read access to this view.
+ </para>
+
+ <para>
+ <structname>pg_stats</structname> is also designed to present the
+ information in a more readable format than the underlying catalog
+ — at the cost that its schema must be extended whenever new slot types
+ are defined for <link linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link>.
+ </para>
+
+ <table>
+ <title><structname>pg_stats</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing table
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>tablename</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
+ </para>
+ <para>
+ Name of table
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>attname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>.<structfield>attname</structfield>)
+ </para>
+ <para>
+ Name of column described by this row
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>inherited</structfield> <type>bool</type>
+ </para>
+ <para>
+ If true, this row includes inheritance child columns, not just the
+ values in the specified table
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>null_frac</structfield> <type>float4</type>
+ </para>
+ <para>
+ Fraction of column entries that are null
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>avg_width</structfield> <type>int4</type>
+ </para>
+ <para>
+ Average width in bytes of column's entries
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>n_distinct</structfield> <type>float4</type>
+ </para>
+ <para>
+ If greater than zero, the estimated number of distinct values in the
+ column. If less than zero, the negative of the number of distinct
+ values divided by the number of rows. (The negated form is used when
+ <command>ANALYZE</command> believes that the number of distinct values is
+ likely to increase as the table grows; the positive form is used when
+ the column seems to have a fixed number of possible values.) For
+ example, -1 indicates a unique column in which the number of distinct
+ values is the same as the number of rows.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_vals</structfield> <type>anyarray</type>
+ </para>
+ <para>
+ A list of the most common values in the column. (Null if
+ no values seem to be more common than any others.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_freqs</structfield> <type>float4[]</type>
+ </para>
+ <para>
+ A list of the frequencies of the most common values,
+ i.e., number of occurrences of each divided by total number of rows.
+ (Null when <structfield>most_common_vals</structfield> is.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>histogram_bounds</structfield> <type>anyarray</type>
+ </para>
+ <para>
+ A list of values that divide the column's values into groups of
+ approximately equal population. The values in
+ <structfield>most_common_vals</structfield>, if present, are omitted from this
+ histogram calculation. (This column is null if the column data type
+ does not have a <literal><</literal> operator or if the
+ <structfield>most_common_vals</structfield> list accounts for the entire
+ population.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>correlation</structfield> <type>float4</type>
+ </para>
+ <para>
+ Statistical correlation between physical row ordering and
+ logical ordering of the column values. This ranges from -1 to +1.
+ When the value is near -1 or +1, an index scan on the column will
+ be estimated to be cheaper than when it is near zero, due to reduction
+ of random access to the disk. (This column is null if the column data
+ type does not have a <literal><</literal> operator.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_elems</structfield> <type>anyarray</type>
+ </para>
+ <para>
+ A list of non-null element values most often appearing within values of
+ the column. (Null for scalar types.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_elem_freqs</structfield> <type>float4[]</type>
+ </para>
+ <para>
+ A list of the frequencies of the most common element values, i.e., the
+ fraction of rows containing at least one instance of the given value.
+ Two or three additional values follow the per-element frequencies;
+ these are the minimum and maximum of the preceding per-element
+ frequencies, and optionally the frequency of null elements.
+ (Null when <structfield>most_common_elems</structfield> is.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>elem_count_histogram</structfield> <type>float4[]</type>
+ </para>
+ <para>
+ A histogram of the counts of distinct non-null element values within the
+ values of the column, followed by the average number of distinct
+ non-null elements. (Null for scalar types.)
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ The maximum number of entries in the array fields can be controlled on a
+ column-by-column basis using the <link linkend="sql-altertable"><command>ALTER
+ TABLE SET STATISTICS</command></link>
+ command, or globally by setting the
+ <xref linkend="guc-default-statistics-target"/> run-time parameter.
+ </para>
+
+ </sect1>
+
+ <sect1 id="view-pg-stats-ext">
+ <title><structname>pg_stats_ext</structname></title>
+
+ <indexterm zone="view-pg-stats-ext">
+ <primary>pg_stats_ext</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_stats_ext</structname> provides access to
+ information about each extended statistics object in the database,
+ combining information stored in the <link
+ linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>
+ and <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>
+ catalogs. This view allows access only to rows of
+ <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link> and <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>
+ that correspond to tables the user has permission to read, and therefore
+ it is safe to allow public read access to this view.
+ </para>
+
+ <para>
+ <structname>pg_stats_ext</structname> is also designed to present the
+ information in a more readable format than the underlying catalogs
+ — at the cost that its schema must be extended whenever new types
+ of extended statistics are added to <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>.
+ </para>
+
+ <table>
+ <title><structname>pg_stats_ext</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing table
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>tablename</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
+ </para>
+ <para>
+ Name of table
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>statistics_schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing extended statistics object
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>statistics_name</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>.<structfield>stxname</structfield>)
+ </para>
+ <para>
+ Name of extended statistics object
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>statistics_owner</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
+ </para>
+ <para>
+ Owner of the extended statistics object
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>attnames</structfield> <type>name[]</type>
+ (references <link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>.<structfield>attname</structfield>)
+ </para>
+ <para>
+ Names of the columns included in the extended statistics object
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>exprs</structfield> <type>text[]</type>
+ </para>
+ <para>
+ Expressions included in the extended statistics object
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>kinds</structfield> <type>char[]</type>
+ </para>
+ <para>
+ Types of extended statistics object enabled for this record
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>inherited</structfield> <type>bool</type>
+ (references <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>.<structfield>stxdinherit</structfield>)
+ </para>
+ <para>
+ If true, the stats include inheritance child columns, not just the
+ values in the specified relation
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>n_distinct</structfield> <type>pg_ndistinct</type>
+ </para>
+ <para>
+ N-distinct counts for combinations of column values. If greater
+ than zero, the estimated number of distinct values in the combination.
+ If less than zero, the negative of the number of distinct values divided
+ by the number of rows.
+ (The negated form is used when <command>ANALYZE</command> believes that
+ the number of distinct values is likely to increase as the table grows;
+ the positive form is used when the column seems to have a fixed number
+ of possible values.) For example, -1 indicates a unique combination of
+ columns in which the number of distinct combinations is the same as the
+ number of rows.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>dependencies</structfield> <type>pg_dependencies</type>
+ </para>
+ <para>
+ Functional dependency statistics
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_vals</structfield> <type>text[]</type>
+ </para>
+ <para>
+ A list of the most common combinations of values in the columns.
+ (Null if no combinations seem to be more common than any others.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_val_nulls</structfield> <type>bool[]</type>
+ </para>
+ <para>
+ A list of NULL flags for the most common combinations of values.
+ (Null when <structfield>most_common_vals</structfield> is.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_freqs</structfield> <type>float8[]</type>
+ </para>
+ <para>
+ A list of the frequencies of the most common combinations,
+ i.e., number of occurrences of each divided by total number of rows.
+ (Null when <structfield>most_common_vals</structfield> is.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_base_freqs</structfield> <type>float8[]</type>
+ </para>
+ <para>
+ A list of the base frequencies of the most common combinations,
+ i.e., product of per-value frequencies.
+ (Null when <structfield>most_common_vals</structfield> is.)
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ The maximum number of entries in the array fields can be controlled on a
+ column-by-column basis using the <link linkend="sql-altertable"><command>ALTER
+ TABLE SET STATISTICS</command></link> command, or globally by setting the
+ <xref linkend="guc-default-statistics-target"/> run-time parameter.
+ </para>
+
+ </sect1>
+
+ <sect1 id="view-pg-stats-ext-exprs">
+ <title><structname>pg_stats_ext_exprs</structname></title>
+
+ <indexterm zone="view-pg-stats-ext-exprs">
+ <primary>pg_stats_ext_exprs</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_stats_ext_exprs</structname> provides access to
+ information about all expressions included in extended statistics objects,
+ combining information stored in the <link
+ linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>
+ and <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>
+ catalogs. This view allows access only to rows of
+ <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link> and <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>
+ that correspond to tables the user has permission to read, and therefore
+ it is safe to allow public read access to this view.
+ </para>
+
+ <para>
+ <structname>pg_stats_ext_exprs</structname> is also designed to present
+ the information in a more readable format than the underlying catalogs
+ — at the cost that its schema must be extended whenever the structure
+ of statistics in <structname>pg_statistic_ext</structname> changes.
+ </para>
+
+ <table>
+ <title><structname>pg_stats_ext_exprs</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing table
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>tablename</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
+ </para>
+ <para>
+ Name of table the statistics object is defined on
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>statistics_schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing extended statistics object
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>statistics_name</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>.<structfield>stxname</structfield>)
+ </para>
+ <para>
+ Name of extended statistics object
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>statistics_owner</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
+ </para>
+ <para>
+ Owner of the extended statistics object
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>expr</structfield> <type>text</type>
+ </para>
+ <para>
+ Expression included in the extended statistics object
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>inherited</structfield> <type>bool</type>
+ (references <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>.<structfield>stxdinherit</structfield>)
+ </para>
+ <para>
+ If true, the stats include inheritance child columns, not just the
+ values in the specified relation
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>null_frac</structfield> <type>float4</type>
+ </para>
+ <para>
+ Fraction of expression entries that are null
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>avg_width</structfield> <type>int4</type>
+ </para>
+ <para>
+ Average width in bytes of expression's entries
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>n_distinct</structfield> <type>float4</type>
+ </para>
+ <para>
+ If greater than zero, the estimated number of distinct values in the
+ expression. If less than zero, the negative of the number of distinct
+ values divided by the number of rows. (The negated form is used when
+ <command>ANALYZE</command> believes that the number of distinct values is
+ likely to increase as the table grows; the positive form is used when
+ the expression seems to have a fixed number of possible values.) For
+ example, -1 indicates a unique expression in which the number of distinct
+ values is the same as the number of rows.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_vals</structfield> <type>anyarray</type>
+ </para>
+ <para>
+ A list of the most common values in the expression. (Null if
+ no values seem to be more common than any others.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_freqs</structfield> <type>float4[]</type>
+ </para>
+ <para>
+ A list of the frequencies of the most common values,
+ i.e., number of occurrences of each divided by total number of rows.
+ (Null when <structfield>most_common_vals</structfield> is.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>histogram_bounds</structfield> <type>anyarray</type>
+ </para>
+ <para>
+ A list of values that divide the expression's values into groups of
+ approximately equal population. The values in
+ <structfield>most_common_vals</structfield>, if present, are omitted from this
+ histogram calculation. (This expression is null if the expression data type
+ does not have a <literal><</literal> operator or if the
+ <structfield>most_common_vals</structfield> list accounts for the entire
+ population.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>correlation</structfield> <type>float4</type>
+ </para>
+ <para>
+ Statistical correlation between physical row ordering and
+ logical ordering of the expression values. This ranges from -1 to +1.
+ When the value is near -1 or +1, an index scan on the expression will
+ be estimated to be cheaper than when it is near zero, due to reduction
+ of random access to the disk. (This expression is null if the expression's
+ data type does not have a <literal><</literal> operator.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_elems</structfield> <type>anyarray</type>
+ </para>
+ <para>
+ A list of non-null element values most often appearing within values of
+ the expression. (Null for scalar types.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_elem_freqs</structfield> <type>float4[]</type>
+ </para>
+ <para>
+ A list of the frequencies of the most common element values, i.e., the
+ fraction of rows containing at least one instance of the given value.
+ Two or three additional values follow the per-element frequencies;
+ these are the minimum and maximum of the preceding per-element
+ frequencies, and optionally the frequency of null elements.
+ (Null when <structfield>most_common_elems</structfield> is.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>elem_count_histogram</structfield> <type>float4[]</type>
+ </para>
+ <para>
+ A histogram of the counts of distinct non-null element values within the
+ values of the expression, followed by the average number of distinct
+ non-null elements. (Null for scalar types.)
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ The maximum number of entries in the array fields can be controlled on a
+ column-by-column basis using the <link linkend="sql-altertable"><command>ALTER
+ TABLE SET STATISTICS</command></link> command, or globally by setting the
+ <xref linkend="guc-default-statistics-target"/> run-time parameter.
+ </para>
+
+ </sect1>
+
+ <sect1 id="view-pg-tables">
+ <title><structname>pg_tables</structname></title>
+
+ <indexterm zone="view-pg-tables">
+ <primary>pg_tables</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_tables</structname> provides access to
+ useful information about each table in the database.
+ </para>
+
+ <table>
+ <title><structname>pg_tables</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing table
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>tablename</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
+ </para>
+ <para>
+ Name of table
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>tableowner</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
+ </para>
+ <para>
+ Name of table's owner
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>tablespace</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-tablespace"><structname>pg_tablespace</structname></link>.<structfield>spcname</structfield>)
+ </para>
+ <para>
+ Name of tablespace containing table (null if default for database)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>hasindexes</structfield> <type>bool</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relhasindex</structfield>)
+ </para>
+ <para>
+ True if table has (or recently had) any indexes
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>hasrules</structfield> <type>bool</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relhasrules</structfield>)
+ </para>
+ <para>
+ True if table has (or once had) rules
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>hastriggers</structfield> <type>bool</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relhastriggers</structfield>)
+ </para>
+ <para>
+ True if table has (or once had) triggers
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>rowsecurity</structfield> <type>bool</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relrowsecurity</structfield>)
+ </para>
+ <para>
+ True if row security is enabled on the table
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ </sect1>
+
+ <sect1 id="view-pg-timezone-abbrevs">
+ <title><structname>pg_timezone_abbrevs</structname></title>
+
+ <indexterm zone="view-pg-timezone-abbrevs">
+ <primary>pg_timezone_abbrevs</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_timezone_abbrevs</structname> provides a list
+ of time zone abbreviations that are currently recognized by the datetime
+ input routines. The contents of this view change when the
+ <xref linkend="guc-timezone-abbreviations"/> run-time parameter is modified.
+ </para>
+
+ <table>
+ <title><structname>pg_timezone_abbrevs</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>abbrev</structfield> <type>text</type>
+ </para>
+ <para>
+ Time zone abbreviation
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>utc_offset</structfield> <type>interval</type>
+ </para>
+ <para>
+ Offset from UTC (positive means east of Greenwich)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>is_dst</structfield> <type>bool</type>
+ </para>
+ <para>
+ True if this is a daylight-savings abbreviation
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ While most timezone abbreviations represent fixed offsets from UTC,
+ there are some that have historically varied in value
+ (see <xref linkend="datetime-config-files"/> for more information).
+ In such cases this view presents their current meaning.
+ </para>
+
+ </sect1>
+
+ <sect1 id="view-pg-timezone-names">
+ <title><structname>pg_timezone_names</structname></title>
+
+ <indexterm zone="view-pg-timezone-names">
+ <primary>pg_timezone_names</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_timezone_names</structname> provides a list
+ of time zone names that are recognized by <command>SET TIMEZONE</command>,
+ along with their associated abbreviations, UTC offsets,
+ and daylight-savings status. (Technically,
+ <productname>PostgreSQL</productname> does not use UTC because leap
+ seconds are not handled.)
+ Unlike the abbreviations shown in <link
+ linkend="view-pg-timezone-abbrevs"><structname>pg_timezone_abbrevs</structname></link>, many of these names imply a set of daylight-savings transition
+ date rules. Therefore, the associated information changes across local DST
+ boundaries. The displayed information is computed based on the current
+ value of <function>CURRENT_TIMESTAMP</function>.
+ </para>
+
+ <table>
+ <title><structname>pg_timezone_names</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>name</structfield> <type>text</type>
+ </para>
+ <para>
+ Time zone name
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>abbrev</structfield> <type>text</type>
+ </para>
+ <para>
+ Time zone abbreviation
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>utc_offset</structfield> <type>interval</type>
+ </para>
+ <para>
+ Offset from UTC (positive means east of Greenwich)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>is_dst</structfield> <type>bool</type>
+ </para>
+ <para>
+ True if currently observing daylight savings
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ </sect1>
+
+ <sect1 id="view-pg-user">
+ <title><structname>pg_user</structname></title>
+
+ <indexterm zone="view-pg-user">
+ <primary>pg_user</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_user</structname> provides access to
+ information about database users. This is simply a publicly
+ readable view of
+ <link linkend="view-pg-shadow"><structname>pg_shadow</structname></link>
+ that blanks out the password field.
+ </para>
+
+ <table>
+ <title><structname>pg_user</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>usename</structfield> <type>name</type>
+ </para>
+ <para>
+ User name
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>usesysid</structfield> <type>oid</type>
+ </para>
+ <para>
+ ID of this user
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>usecreatedb</structfield> <type>bool</type>
+ </para>
+ <para>
+ User can create databases
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>usesuper</structfield> <type>bool</type>
+ </para>
+ <para>
+ User is a superuser
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>userepl</structfield> <type>bool</type>
+ </para>
+ <para>
+ User can initiate streaming replication and put the system in and
+ out of backup mode.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>usebypassrls</structfield> <type>bool</type>
+ </para>
+ <para>
+ User bypasses every row-level security policy, see
+ <xref linkend="ddl-rowsecurity"/> for more information.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>passwd</structfield> <type>text</type>
+ </para>
+ <para>
+ Not the password (always reads as <literal>********</literal>)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>valuntil</structfield> <type>timestamptz</type>
+ </para>
+ <para>
+ Password expiry time (only used for password authentication)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>useconfig</structfield> <type>text[]</type>
+ </para>
+ <para>
+ Session defaults for run-time configuration variables
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ </sect1>
+
+ <sect1 id="view-pg-user-mappings">
+ <title><structname>pg_user_mappings</structname></title>
+
+ <indexterm zone="view-pg-user-mappings">
+ <primary>pg_user_mappings</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_user_mappings</structname> provides access
+ to information about user mappings. This is essentially a publicly
+ readable view of
+ <link linkend="catalog-pg-user-mapping"><structname>pg_user_mapping</structname></link>
+ that leaves out the options field if the user has no rights to use
+ it.
+ </para>
+
+ <table>
+ <title><structname>pg_user_mappings</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>umid</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-user-mapping"><structname>pg_user_mapping</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ OID of the user mapping
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>srvid</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-foreign-server"><structname>pg_foreign_server</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ The OID of the foreign server that contains this mapping
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>srvname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-foreign-server"><structname>pg_foreign_server</structname></link>.<structfield>srvname</structfield>)
+ </para>
+ <para>
+ Name of the foreign server
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>umuser</structfield> <type>oid</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>oid</structfield>)
+ </para>
+ <para>
+ OID of the local role being mapped, or zero if the user mapping is public
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>usename</structfield> <type>name</type>
+ </para>
+ <para>
+ Name of the local user to be mapped
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>umoptions</structfield> <type>text[]</type>
+ </para>
+ <para>
+ User mapping specific options, as <quote>keyword=value</quote> strings
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ To protect password information stored as a user mapping option,
+ the <structfield>umoptions</structfield> column will read as null
+ unless one of the following applies:
+ <itemizedlist>
+ <listitem>
+ <para>
+ current user is the user being mapped, and owns the server or
+ holds <literal>USAGE</literal> privilege on it
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ current user is the server owner and mapping is for <literal>PUBLIC</literal>
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ current user is a superuser
+ </para>
+ </listitem>
+ </itemizedlist>
+ </para>
+
+ </sect1>
+
+
+ <sect1 id="view-pg-views">
+ <title><structname>pg_views</structname></title>
+
+ <indexterm zone="view-pg-views">
+ <primary>pg_views</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_views</structname> provides access to
+ useful information about each view in the database.
+ </para>
+
+ <table>
+ <title><structname>pg_views</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing view
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>viewname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
+ </para>
+ <para>
+ Name of view
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>viewowner</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
+ </para>
+ <para>
+ Name of view's owner
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>definition</structfield> <type>text</type>
+ </para>
+ <para>
+ View definition (a reconstructed <xref linkend="sql-select"/> query)
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </sect1>
+
+</chapter>
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