</para>
<para>
Deduplication works by periodically merging groups of duplicate
- tuples together, forming a single posting list tuple for each
+ tuples together, forming a single <firstterm>posting list</firstterm> tuple for each
group. The column key value(s) only appear once in this
representation. This is followed by a sorted array of
<acronym>TID</acronym>s that point to rows in the table. This
of statistics accumulated for this statistics object by
<xref linkend="sql-analyze"/>.
A zero value indicates that no statistics should be collected.
- A negative value says to use the system default statistics target.
+ A negative value says to use the maximum of the statistics targets of
+ the referenced columns, if set, or the system default statistics target.
Positive values of <structfield>stxstattarget</structfield>
determine the target number of <quote>most common values</quote>
to collect.
servers or streaming base backup clients (i.e., the maximum number of
simultaneously running WAL sender processes). The default is
<literal>10</literal>. The value <literal>0</literal> means
- replication is disabled. Abrupt streaming client disconnection might
+ replication is disabled. Abrupt disconnection of a streaming client might
leave an orphaned connection slot behind until a timeout is reached,
so this parameter should be set slightly higher than the maximum
number of expected clients so disconnected clients can immediately
slots</link> are allowed to retain in the <filename>pg_wal</filename>
directory at checkpoint time.
If <varname>max_slot_wal_keep_size</varname> is -1 (the default),
- replication slots retain unlimited amount of WAL files. If
- restart_lsn of a replication slot gets behind more than that megabytes
- from the current LSN, the standby using the slot may no longer be able
+ replication slots may retain an unlimited amount of WAL files. Otherwise, if
+ restart_lsn of a replication slot falls behind the current LSN by more
+ than the given size, the standby using the slot may no longer be able
to continue replication due to removal of required WAL files. You
can see the WAL availability of replication slots
in <link linkend="view-pg-replication-slots">pg_replication_slots</link>.
</term>
<listitem>
<para>
- If greater than zero, each bind parameter value reported in
- non-error statement-logging messages is trimmed to this many bytes.
- Zero disables logging bind parameters with statements.
+ If greater than zero, each bind parameter value logged with a
+ non-error statement-logging message is trimmed to this many bytes.
+ Zero disables logging of bind parameters for non-error statement logs.
<literal>-1</literal> (the default) allows bind parameters to be
logged in full.
If this value is specified without units, it is taken as bytes.
a regular <command>VACUUM</command> in that it visits every page that might
contain unfrozen XIDs or MXIDs, not just those that might contain dead
tuples. The default is 150 million transactions. Although users can
- set this value anywhere from zero to two billions, <command>VACUUM</command>
+ set this value anywhere from zero to two billion, <command>VACUUM</command>
will silently limit the effective value to 95% of
<xref linkend="guc-autovacuum-freeze-max-age"/>, so that a
- periodical manual <command>VACUUM</command> has a chance to run before an
+ periodic manual <command>VACUUM</command> has a chance to run before an
anti-wraparound autovacuum is launched for the table. For more
information see
<xref linkend="vacuum-for-wraparound"/>.
a regular <command>VACUUM</command> in that it visits every page that might
contain unfrozen XIDs or MXIDs, not just those that might contain dead
tuples. The default is 150 million multixacts.
- Although users can set this value anywhere from zero to two billions,
+ Although users can set this value anywhere from zero to two billion,
<command>VACUUM</command> will silently limit the effective value to 95% of
<xref linkend="guc-autovacuum-multixact-freeze-max-age"/>, so that a
- periodical manual <command>VACUUM</command> has a chance to run before an
+ periodic manual <command>VACUUM</command> has a chance to run before an
anti-wraparound is launched for the table.
For more information see <xref linkend="vacuum-for-multixact-wraparound"/>.
</para>
Before running the <command>ATTACH PARTITION</command> command, it is
recommended to create a <literal>CHECK</literal> constraint on the table to
be attached matching the desired partition constraint. That way,
- the system will be able to skip the scan to validate the implicit
+ the system will be able to skip the scan which is otherwise needed to validate the implicit
partition constraint. Without the <literal>CHECK</literal> constraint,
the table will be scanned to validate the partition constraint while
holding an <literal>ACCESS EXCLUSIVE</literal> lock on that partition
<literal>'use_json_null'</literal>.
</para>
<para>
- <literal>jsonb_set_lax('[{"f1":1,"f2":null},2,null,3]', '{0,f1}',null)</literal>
+ <literal>jsonb_set_lax('[{"f1":1,"f2":null},2,null,3]', '{0,f1}', null)</literal>
<returnvalue>[{"f1":null,"f2":null},2,null,3]</returnvalue>
</para>
<para>
- <literal>jsonb_set_lax('[{"f1":99,"f2":null},2]', '{0,f3}',null, true, 'return_target')</literal>
+ <literal>jsonb_set_lax('[{"f1":99,"f2":null},2]', '{0,f3}', null, true, 'return_target')</literal>
<returnvalue>[{"f1": 99, "f2": null}, 2]</returnvalue>
</para></entry>
</row>
<term><literal>connect_timeout</literal></term>
<listitem>
<para>
- Maximum wait for connection, in seconds (write as a decimal integer,
+ Maximum time to wait while connecting, in seconds (write as a decimal integer,
e.g., <literal>10</literal>). Zero, negative, or not specified means
wait indefinitely. The minimum allowed timeout is 2 seconds, therefore
a value of <literal>1</literal> is interpreted as <literal>2</literal>.
<listitem>
<para>
Replication is only supported by tables, including partitioned tables.
- Attempts to replicate other types of relations such as views, materialized
+ Attempts to replicate other types of relations, such as views, materialized
views, or foreign tables, will result in an error.
</para>
</listitem>
<entry><literal>waiting for checkpoint to finish</literal></entry>
<entry>
The WAL sender process is currently performing
- <function>pg_start_backup</function> to set up for
- taking a base backup, and waiting for backup start
+ <function>pg_start_backup</function> to prepare to
+ take a base backup, and waiting for the start-of-backup
checkpoint to finish.
</entry>
</row>
and sent along with the backup. The manifest is a list of every
file present in the backup with the exception of any WAL files that
may be included. It also stores the size, last modification time, and
- an optional checksum for each file.
+ optionally a checksum for each file.
A value of <literal>force-encode</literal> forces all filenames
to be hex-encoded; otherwise, this type of encoding is performed only
for files whose names are non-UTF8 octet sequences.
<term><literal>MANIFEST_CHECKSUMS</literal> <replaceable>checksum_algorithm</replaceable></term>
<listitem>
<para>
- Specifies the algorithm that should be applied to each file included
+ Specifies the checksum algorithm that should be applied to each file included
in the backup manifest. Currently, the available
algorithms are <literal>NONE</literal>, <literal>CRC32C</literal>,
<literal>SHA224</literal>, <literal>SHA256</literal>,
The statistic-gathering target for this statistics object for subsequent
<xref linkend="sql-analyze"/> operations.
The target can be set in the range 0 to 10000; alternatively, set it
- to -1 to revert to using the system default statistics
+ to -1 to revert to using the maximum of the statistics target of the
+ referenced columns, if set, or the system default statistics
target (<xref linkend="guc-default-statistics-target"/>).
For more information on the use of statistics by the
<productname>PostgreSQL</productname> query planner, refer to
When applied to a partitioned table, nothing is moved, but any
partitions created afterwards with
<command>CREATE TABLE PARTITION OF</command> will use that tablespace,
- unless the <literal>TABLESPACE</literal> clause is used to override it.
+ unless overridden by a <literal>TABLESPACE</literal> clause.
</para>
<para>
</para>
<para>
The following command-line options control the generation of the
- backup and the running of the program:
+ backup and the invocation of the program:
<variablelist>
<varlistentry>
of each file for users who wish to verify that the backup has not been
tampered with, while the CRC32C algorithm provides a checksum that is
much faster to calculate; it is good at catching errors due to accidental
- changes but is not resistant to targeted modifications. Note that, to
+ changes but is not resistant to malicious modifications. Note that, to
be useful against an adversary who has access to the backup, the backup
manifest would need to be stored securely elsewhere or otherwise
verified not to have been modified since the backup was taken.
<listitem>
<para>
Run the dump in parallel by dumping <replaceable class="parameter">njobs</replaceable>
- tables simultaneously. This option reduces the time of the dump but it also
+ tables simultaneously. This option may reduce the time needed to perform the dump but it also
increases the load on the database server. You can only use this option with the
directory output format because this is the only output format where multiple processes
can write their data at the same time.
<command>pg_rewind</command> to return without waiting, which is
faster, but means that a subsequent operating system crash can leave
the synchronized data directory corrupt. Generally, this option is
- useful for testing but should not be used when creating a production
+ useful for testing but should not be used on a production
installation.
</para>
</listitem>
<para>
When executing <application>pg_rewind</application> using an online
cluster as source which has been recently promoted, it is necessary
- to execute a <command>CHECKPOINT</command> after promotion so as its
+ to execute a <command>CHECKPOINT</command> after promotion such that its
control file reflects up-to-date timeline information, which is used by
<application>pg_rewind</application> to check if the target cluster
can be rewound using the designated source cluster.
<title>Common Options</title>
<para>
- <application>pgbench</application> accepts the following command-line
- common arguments:
+ <application>pgbench</application> also accepts the following common command-line
+ arguments for connection parameters:
<variablelist>
<para>
Reindexing a single index or table requires being the owner of that
index or table. Reindexing a schema or database requires being the
- owner of that schema or database. Note that is therefore sometimes
+ owner of that schema or database. Note specifically that it's thus
possible for non-superusers to rebuild indexes of tables owned by
other users. However, as a special exception, when
<command>REINDEX DATABASE</command>, <command>REINDEX SCHEMA</command>
<para>
Execute the reindex commands in parallel by running
<replaceable class="parameter">njobs</replaceable>
- commands simultaneously. This option reduces the time of the
- processing but it also increases the load on the database server.
+ commands simultaneously. This option may reduce the processing time
+ but it also increases the load on the database server.
</para>
<para>
<application>reindexdb</application> will open
<para>
Execute the vacuum or analyze commands in parallel by running
<replaceable class="parameter">njobs</replaceable>
- commands simultaneously. This option reduces the time of the
- processing but it also increases the load on the database server.
+ commands simultaneously. This option may reduce the processing time
+ but it also increases the load on the database server.
</para>
<para>
<application>vacuumdb</application> will open
<para>
The <productname>PostgreSQL</productname> server will listen for both
normal and <acronym>GSSAPI</acronym>-encrypted connections on the same TCP
- port, and will negotiate with any connecting client on whether to
+ port, and will negotiate with any connecting client whether to
use <acronym>GSSAPI</acronym> for encryption (and for authentication). By
default, this decision is up to the client (which means it can be
downgraded by an attacker); see <xref linkend="auth-pg-hba-conf"/> about
<title>Use of Quotes</title>
<para>
- Use quotes always to delimit file names, user-supplied identifiers, and
+ Always use quotes to delimit file names, user-supplied identifiers, and
other variables that might contain words. Do not use them to mark up
variables that will not contain words (for example, operator names).
</para>
Deletion algorithm keeps exclusive locks on left siblings of pages comprising
currently investigated path. Thus, if current page is to be removed, all
required pages to remove both downlink and rightlink are already locked. That
-evades potential right to left page locking order, which could deadlock with
+avoids potential right to left page locking order, which could deadlock with
concurrent stepping right.
A search concurrent to page deletion might already have read a pointer to the
* executeItemOptUnwrapTarget() function have 'unwrap' argument, which indicates
* whether unwrapping of array is needed. When unwrap == true, each of array
* members is passed to executeItemOptUnwrapTarget() again but with unwrap == false
- * in order to evade subsequent array unwrapping.
+ * in order to avoid subsequent array unwrapping.
*
* All boolean expressions (predicates) are evaluated by executeBoolItem()
* function, which returns tri-state JsonPathBool. When error is occurred
-- This tests that when merging partitions from plt1_adv and plt2_adv in
-- merge_list_bounds(), process_outer_partition() returns an already-assigned
-- merged partition when re-called with plt1_adv_p1 for the second list value
--- '0001' of that partitin
+-- '0001' of that partition
EXPLAIN (COSTS OFF)
SELECT t1.a, t1.c, t2.a, t2.c, t3.a, t3.c FROM (plt1_adv t1 LEFT JOIN plt2_adv t2 ON (t1.c = t2.c)) FULL JOIN plt3_adv t3 ON (t1.c = t3.c) WHERE coalesce(t1.a, 0) % 5 != 3 AND coalesce(t1.a, 0) % 5 != 4 ORDER BY t1.c, t1.a, t2.a, t3.a;
QUERY PLAN
-- This tests that when merging partitions from plt1_adv and plt2_adv in
-- merge_list_bounds(), process_outer_partition() returns an already-assigned
-- merged partition when re-called with plt1_adv_p1 for the second list value
--- '0001' of that partitin
+-- '0001' of that partition
EXPLAIN (COSTS OFF)
SELECT t1.a, t1.c, t2.a, t2.c, t3.a, t3.c FROM (plt1_adv t1 LEFT JOIN plt2_adv t2 ON (t1.c = t2.c)) FULL JOIN plt3_adv t3 ON (t1.c = t3.c) WHERE coalesce(t1.a, 0) % 5 != 3 AND coalesce(t1.a, 0) % 5 != 4 ORDER BY t1.c, t1.a, t2.a, t3.a;
SELECT t1.a, t1.c, t2.a, t2.c, t3.a, t3.c FROM (plt1_adv t1 LEFT JOIN plt2_adv t2 ON (t1.c = t2.c)) FULL JOIN plt3_adv t3 ON (t1.c = t3.c) WHERE coalesce(t1.a, 0) % 5 != 3 AND coalesce(t1.a, 0) % 5 != 4 ORDER BY t1.c, t1.a, t2.a, t3.a;
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