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+<!-- $PostgreSQL: pgsql/doc/src/sgml/release-9.1.sgml,v 1.1 2010/09/02 17:30:06 tgl Exp $ -->
+
+<!-- This is up-to-date with commits through 2010-09-01 -->
+
+<sect1 id="release-9-1-alpha">
+ <title>Release 9.1alpha1</title>
+ <sect2>
+ <title>Overview</title>
+ <para>
+ PostgreSQL alpha releases are snapshots of development code. They
+ are intended to preview and test upcoming features and to provide
+ the possibility for early feedback. They should not be used in
+ production installations or active development projects. While the
+ PostgreSQL code is continuously subject to a number of automated
+ and manual tests, alpha releases might have serious bugs. Also
+ features may be changed incompatibly or removed at any time during
+ the development cycle.
+ </para>
+ <para>
+ The development cycle of a PostgreSQL major release alternates
+ between periods of development and periods of integration work,
+ called commit fests, normally one month each. Alpha releases are
+ planned to be produced at the end of every commit fest, thus every
+ two months. Since the first commit fest starts within a month from
+ the beginning of development altogether, early alpha releases are
+ not indicative of the likely feature set of the final release.
+ </para>
+ <para>
+ The release notes below highlight user visible changes and new
+ features. There are normally numerous bug fixes and performance
+ improvements in every new snapshot of PostgreSQL, and it would be
+ too bulky to attempt to list them all. Note that many bug fixes are
+ also backported to stable releases of PostgreSQL, and you should be
+ using those if you are looking for bug-fix-only upgrades for your
+ current installations.
+ </para>
+ <para>
+ These notes are cumulative over all alpha releases of the current
+ development cycle. Items that are new in the latest alpha release are
+ <emphasis>emphasized</emphasis>.
+ </para>
+ </sect2>
+ <sect2>
+ <title>Migration</title>
+ <para>
+ To upgrade from any release to an alpha release or from an alpha
+ release to any other release will most likely require a
+ dump/restore upgrade procedure. It may happen that this is not
+ necessary in particular cases, but that is not verified beforehand.
+ (The server will warn you in any case when a dump/restore is
+ necessary if you attempt to use it with an old data directory.)
+ Note, however, that the dump/restore upgrade procedure is expected
+ to work for alpha releases, and problems in this area should be
+ reported.
+ </para>
+ </sect2>
+ <sect2>
+ <title>Testing</title>
+ <para>
+ The primary reason we release alphas is to get users to test new
+ features as early as possible. If you are interested in helping
+ with organized testing, please see
+ <ulink url="http://wiki.postgresql.org/wiki/HowToBetaTest">the
+ testing information page</ulink>.
+ </para>
+ </sect2>
+ <sect2>
+ <title>Changes</title>
+ <sect3>
+ <title>SQL Features</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ <emphasis>Recognize functional dependency on primary
+ keys</emphasis>
+ </para>
+ <para>
+ This allows a table's other columns to be referenced without listing
+ them in GROUP BY, so long as the primary key column(s) are listed in
+ GROUP BY.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Add CREATE TABLE IF NOT EXISTS</emphasis>
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </sect3>
+ <sect3>
+ <title>Performance</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ <emphasis>Reduce lock levels of CREATE TRIGGER and some ALTER
+ TABLE, CREATE RULE actions</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Add some knowledge about prefix matches to
+ tsmatchsel()</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Replace the naive HYPOT() macro with a
+ standards-conformant hypotenuse function</emphasis>
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </sect3>
+ <sect3>
+ <title>Server Settings</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ <emphasis>Change the default value of
+ <literal>standard_conforming_strings</> to
+ <literal>on</></emphasis>
+ </para>
+ <warning>
+ <para>
+ This is a significant incompatibility with previous releases,
+ because it may break unwary applications in security-critical ways.
+ </para>
+ </warning>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Add <literal>log_file_mode</> parameter</emphasis>
+ </para>
+ <para>
+ This allows control of the file permissions set on log files created
+ by the syslogger process.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Add <literal>restart_after_crash</> parameter</emphasis>
+ </para>
+ <para>
+ Normally, we automatically restart after a backend crash, but in
+ some cases when PostgreSQL is invoked by clusterware it may be
+ desirable to suppress this behavior, so we now provide an option which
+ does that.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </sect3>
+ <sect3>
+ <title>Administration and Monitoring</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ <emphasis>Make EXPLAIN show the function call expression of a
+ FunctionScan plan node, but only in VERBOSE mode</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Make EXPLAIN print PARAM_EXEC Params as
+ the referenced expressions, rather than just $N</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Add vacuum and analyze counters to pg_stat_*_tables
+ views</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Add stats functions and views to provide access to a
+ transaction's own statistics counts</emphasis>
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </sect3>
+ <sect3>
+ <title>Security</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ <emphasis>Add server authentication over Unix-domain
+ sockets</emphasis>
+ </para>
+ <para>
+ This adds a libpq connection parameter <literal>requirepeer</> that
+ specifies the user name that the server process is expected to run
+ under.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </sect3>
+ <sect3>
+ <title>Built-In Functions</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ <emphasis>Add string functions: concat(), concat_ws(), left(),
+ right(), and reverse()</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Add three-parameter forms of array_to_string and
+ string_to_array</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Add XMLEXISTS function</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Add xpath_exists() function</emphasis>
+ </para>
+ <para>
+ This is equivalent to XMLEXISTS except that it offers support for
+ namespace mapping.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Add xml_is_well_formed, xml_is_well_formed_document,
+ xml_is_well_formed_content functions to the core XML
+ code</emphasis>
+ </para>
+ <para>
+ These supersede a version previously offered by contrib/xml2.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </sect3>
+ <sect3>
+ <title>Data Types</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ <emphasis>Allow numeric to use a more compact, 2-byte header in
+ many cases</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Add support for dividing money by money (yielding a
+ float8 result) and for casting between money and numeric</emphasis>
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </sect3>
+ <sect3>
+ <title>Server Tools</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ <emphasis>Add options to force quoting of all
+ identifiers</emphasis>
+ </para>
+ <para>
+ This includes a quote_all_identifiers parameter which affects the
+ behavior of the backend, and a --quote-all-identifiers argument to
+ pg_dump and pg_dumpall which sets the parameter and also affects the
+ quoting done internally by those applications.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </sect3>
+ <sect3>
+ <title>psql</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ <emphasis>Add \conninfo command to psql, to show current connection
+ info</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Extend psql's \e and \ef commands so that a line number
+ can be specified, and the editor's cursor will be initially placed
+ on that line</emphasis>
+ </para>
+ <para>
+ To avoid assumptions about what switch the user's editor takes for
+ this purpose, there is a new psql variable EDITOR_LINENUMBER_SWITCH
+ with (at present) no default value.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Add a \sf (show function) command to psql, for those
+ times when you need to look at a function but don't wish to fire up
+ an editor</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Make psql distinguish between unique indices and unique
+ constraints in \d printout</emphasis>
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </sect3>
+ <sect3>
+ <title>Procedural Languages</title>
+ <sect4>
+ <title>PL/pgSQL</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ <emphasis>Modify the handling of RAISE without parameters so that
+ the error it throws can be caught in the same places that could
+ catch an ordinary RAISE ERROR in the same location</emphasis>
+ </para>
+ <para>
+ The previous coding insisted on throwing the error from the block
+ containing the active exception handler; which is arguably more
+ surprising, and definitely unlike Oracle's behavior.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Remove ancient PL/pgSQL line numbering hack</emphasis>
+ </para>
+ <para>
+ PL/pgSQL used to count the second line of the function body as
+ <quote>line 1</>, if the first line was zero-length.
+ While this hack arguably has some benefit in terms of making
+ PL/pgsql's line numbering match the programmer's expectations, it
+ also makes PL/pgsql inconsistent with the remaining PLs, making it
+ difficult for clients to reliably determine where the error
+ actually is. On balance, it seems better to be consistent.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </sect4>
+ </sect3>
+ <sect3>
+ <title>Additional Supplied Modules</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ <emphasis>Add the ability to compute per-statement latencies (ie,
+ average execution times) to pgbench</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Teach levenshtein() about multi-byte
+ characters</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Add btree_gist support for searching on <quote>not
+ equals</quote></emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Add ssl_cipher() and ssl_version() functions to
+ contrib/sslinfo</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Remove the arbitrary (and undocumented) limit on the
+ number of parameter=value pairs that can be handled by
+ xslt_process()</emphasis>
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </sect3>
+ <sect3>
+ <title>Source Code, Build Options</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ <emphasis>Include the backend ID in the relpath of temporary
+ relations</emphasis>
+ </para>
+ <para>
+ This allows us to reliably remove all leftover temporary relation
+ files on cluster startup without reference to system catalogs or
+ WAL; therefore, we no longer include temporary relations in
+ XLOG_XACT_COMMIT and XLOG_XACT_ABORT WAL records.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Rewrite COMMENT ON <replaceable>object</> code for better
+ modularity, and add necessary locking</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Add a hook in ExecCheckRTPerms() for eventual use by
+ external security-checking modules</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Standardize names and calling conventions of
+ get_whatever_oid functions</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Make NestLoop plan nodes pass outer-relation variables
+ into their inner relation using the general PARAM_EXEC executor
+ parameter mechanism, rather than the ad-hoc kluge of passing the
+ outer tuple down through ExecReScan</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Make details of the Numeric representation private to
+ numeric.c</emphasis>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>Suppress some compiler warnings from
+ <literal>clang</></emphasis>
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </sect3>
+ </sect2>
+</sect1>
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