Add compatibility note warning that plpgsql is now stricter about the column
datatypes of composite results, per gripe from Marcel Asio. Some desultory copy-editing of plpgsql-related sections of the release notes.
This commit is contained in:
Tom Lane
parent
b57ddccf05
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@ -1,4 +1,4 @@
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<!-- $PostgreSQL: pgsql/doc/src/sgml/release-9.0.sgml,v 2.35 2010/06/24 18:33:05 rhaas Exp $ -->
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<!-- $PostgreSQL: pgsql/doc/src/sgml/release-9.0.sgml,v 2.36 2010/06/29 21:20:19 tgl Exp $ -->
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<sect1 id="release-9-0">
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<title>Release 9.0</title>
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@ -30,10 +30,11 @@
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<listitem>
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<para>
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Built-in, binary, log-based replication. This advance consists of two features:
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Hot Standby allows continuous archive standby database servers to accept read-only
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queries, and Streaming Replication allows continuous archive (<acronym>WAL</>) files
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to be streamed over a network port to a standby database server.
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Built-in, binary, log-based replication. This advance consists of two
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features: Hot Standby allows continuous archive standby database servers
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to accept read-only queries, and Streaming Replication allows continuous
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archive (<acronym>WAL</>) files to be streamed over a network port to a
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standby database server.
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</para>
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</listitem>
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@ -54,8 +55,9 @@
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Broadly enhanced stored procedure support.
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The <link linkend="SQL-DO"><command>DO</></link> statement permits
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ad-hoc or anonymous code blocks. Functions can now be called using named
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parameters. PL/pgSQL is now installed by default, and PL/Perl and PL/Python
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have been enhanced in several ways, including support for Python3.
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parameters. PL/pgSQL is now installed by default, and PL/Perl and
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PL/Python have been enhanced in several ways, including support for
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Python3.
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</para>
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</listitem>
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@ -63,7 +65,7 @@
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<para>
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Triggers now support two new features,
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SQL-compliant <link
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linkend="SQL-CREATETRIGGER">per-column triggers</link>, and
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linkend="SQL-CREATETRIGGER">per-column triggers</link>, and
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conditional trigger execution.
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</para>
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</listitem>
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@ -86,7 +88,7 @@
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<listitem>
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<para>
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The <link linkend="SQL-LISTEN"><command>LISTEN</></link>/<link
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linkend="SQL-NOTIFY"><command>NOTIFY</></link>
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linkend="SQL-NOTIFY"><command>NOTIFY</></link>
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feature has been overhauled to make it into
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a high-performance event queuing system. It now stores
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events in a memory-based queue, and it now allows delivery
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@ -134,16 +136,17 @@
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<para>
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A dump/restore using <application>pg_dump</application>
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or use of <application>pg_upgrade</application> is required
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or use of <application>pg_upgrade</application> is required
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for those wishing to migrate data from any previous
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release.
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</para>
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<para>
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Version 9.0 contains a number of changes which selectively break backwards compatibility
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in order to support new features and code quality improvements. Particularly, users
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who make extensive use of PL/pgSQL and/or PITR and Warm Standby should test their
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solutions for breakage. Observe the following incompatibilities:
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Version 9.0 contains a number of changes which selectively break backwards
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compatibility in order to support new features and code quality
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improvements. Particularly, users who make extensive use of PL/pgSQL
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and/or PITR and Warm Standby should test their solutions for breakage.
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Observe the following incompatibilities:
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</para>
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<sect3>
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@ -270,15 +273,15 @@
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<listitem>
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<para>
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No longer change function input variable names via
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<command>REPLACE FUNCTION</command>(Pavel Stehule).
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<command>CREATE OR REPLACE FUNCTION</command> can no longer change
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the declared names of function parameters (Pavel Stehule)
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</para>
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<para>
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In order to support names parameter calls, it is
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no longer possible to change the aliases for input variables
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in the function declaration in place. You now have to <command>DROP
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</command> and recreate the function.
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In order to support named-parameter calls, it is
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no longer allowed to change the aliases for input variables
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in the declaration of an existing function. You now have to
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<command>DROP</command> and recreate the function.
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</para>
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</listitem>
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@ -287,22 +290,52 @@
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</sect3>
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<sect3>
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<title>PL/pgSQL Variables</title>
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<title>PL/pgSQL</title>
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<itemizedlist>
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<listitem>
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<para>
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Have PL/pgSQL throw an error if a variable name conflicts with a
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PL/pgSQL now throws an error if a variable name conflicts with a
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column name used in a query (Tom Lane)
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</para>
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<para>
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This behavior can be changed via the server variable <link
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The former behavior was to bind to variable names in preference to
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query column names, which often resulted in surprising misbehavior.
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Throwing an error allows easy detection of ambiguous situations.
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Although it's recommended that functions encountering this type of
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error be modified to remove the conflict, the old behavior can be
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restored if necessary via the configuration parameter <link
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linkend="plpgsql-var-subst"><varname>plpgsql.variable_conflict</></link>,
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or by the per-function option <literal>#variable_conflict</>.
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The former behavior was to bind to variable names over
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column names, but not consistently. Stored procedures
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with naming conflicts will probably need to be refactored.
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or via the per-function option <literal>#variable_conflict</>.
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</para>
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</listitem>
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<listitem>
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<para>
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PL/pgSQL no longer allows variable names that match SQL
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reserved words (Tom Lane)
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</para>
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<para>
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This is a consequence of aligning the PL/pgSQL parser to match the
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core SQL parser more closely. If necessary,
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variable names can be double-quoted to avoid this restriction.
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</para>
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</listitem>
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<listitem>
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<para>
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PL/pgSQL now requires columns of composite results to match the
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expected type modifier as well as base type (Pavel Stehule, Tom Lane)
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</para>
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<para>
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For example, if a column of the result type is declared as
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<literal>NUMERIC(30,2)</>, it is no longer acceptable to return a
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<literal>NUMERIC</> of some other precision in that column. Previous
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versions neglected to check the type modifier and would thus allow
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result rows that didn't actually conform to the declared restrictions.
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</para>
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</listitem>
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@ -312,21 +345,10 @@
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</para>
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<para>
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Instead, use <link
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linkend="plpgsql-declaration-parameters"><literal>ALIAS</></link>,
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Instead of <literal>RENAME</>, use <link
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linkend="plpgsql-declaration-alias"><literal>ALIAS</></link>,
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which can now alias any variable, not just dollar sign
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variables, e.g. <literal>$1</>.
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</para>
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</listitem>
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<listitem>
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<para>
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PL/pgSQL no longer allows unquoted variables names that match SQL
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reserved words (Tom Lane)
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</para>
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<para>
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Variables can be double-quoted to avoid this restriction.
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parameter names (such as <literal>$1</>).
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</para>
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</listitem>
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</itemizedlist>
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@ -339,12 +361,12 @@
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<listitem>
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<para>
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Remove support for platforms that don't have a working 64-bit
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integer data types (Tom Lane)
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integer data type (Tom Lane)
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</para>
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<para>
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It is believed all supported platforms have working 64-bit integer
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data types.
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It is believed all still-supported platforms have working 64-bit
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integer data types.
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</para>
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</listitem>
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</itemizedlist>
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@ -354,7 +376,7 @@
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<sect2>
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<title>Changes</title>
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<para>
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Version 9.0 has an unprecedented number of new major features,
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Version 9.0 has an unprecedented number of new major features,
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and over 200 enhancements, improvements, new commands,
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new functions, and other changes.
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</para>
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@ -423,8 +445,9 @@
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<title>Performance</title>
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<para>
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Version 9.0 also contains several performance and optimizer enhancements to
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improve specific uses of PostgreSQL and remedy certain poor-performing cases.
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Version 9.0 also contains several performance and optimizer enhancements
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to improve specific uses of PostgreSQL and remedy certain poor-performing
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cases.
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</para>
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<itemizedlist>
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@ -469,7 +492,7 @@
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<para>
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Outer joins where the inner side is unique and not referenced in
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the query are unnecessary and are therefore now removed. This will
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the query are unnecessary and are therefore now removed. This will
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accelerate many automatically generated queries, such as those created
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by object-relational mappers.
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</para>
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@ -651,7 +674,7 @@
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<sect4>
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<title>Monitoring</title>
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<para>
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With increased use of PostgreSQL in high-end production systems,
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With increased use of PostgreSQL in high-end production systems,
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users need increased monitoring. PostgresSQL 9.0 continues to add
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more ways to monitor PostgreSQL applications.
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</para>
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@ -667,7 +690,7 @@
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</para>
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<para>
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This allows DBAs to characterize database traffic
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This allows DBAs to characterize database traffic
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and troubleshoot problems by source application.
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</para>
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</listitem>
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@ -746,7 +769,7 @@
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in the new <structname>pg_db_role_setting</> system table. A new
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<application>psql</> <literal>\drds</> command shows these settings.
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Backwards-compatible system views do not show this information.
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The primary use of this feature is setting schema
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The primary use of this feature is setting schema
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<link linkend="guc-search-path"><varname>search_path</varname></link>.
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</para>
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@ -863,7 +886,7 @@
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</para>
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<para>
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For drivers which support this feature, this saves an entire
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For drivers that support this feature, this saves an entire
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round-trip to the client, allowing result counts and pagination
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to be calculated without a second <command>COUNT</command> query.
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</para>
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@ -1057,13 +1080,13 @@
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TABLE CONSTRAINT ... EXCLUDE</></link> clause. While
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uniqueness checks could be specified using this syntax,
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the real value of this feature is in using complex
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operators that do not have built-in constraints.
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operators that do not have built-in constraints.
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</para>
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<para>
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The primary use of exclusion constraints is to allow defining
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non-overlapping uniqueness, such as for time periods, arrays
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or ranges of values. This supports data integrity at the
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or ranges of values. This supports data integrity at the
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table level for calendaring, time-management, and scientific
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applications.
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</para>
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@ -1134,7 +1157,7 @@
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<para>
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LISTEN/NOTIFY may now be used as a full-featured, high-performance
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event queue system for PostgreSQL, with transactional support
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event queue system for PostgreSQL, with transactional support
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and guaranteed delivery.
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</para>
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</listitem>
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@ -1201,7 +1224,7 @@
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</para>
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<para>
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The new output formats will support the development of new tools
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The new output formats will support the development of new tools
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for analysis of EXPLAIN output.
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</para>
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</listitem>
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@ -1255,7 +1278,7 @@
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</para>
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<para>
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The previous method was usually slower and caused index bloat.
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The previous method was usually slower and caused index bloat.
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Note that the new method may use more disk space during VACUUM
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FULL.
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</para>
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@ -1306,9 +1329,9 @@
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</para>
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<para>
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This feature supports GiST indexing of point operations on polygons,
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This feature supports GiST indexing of point operations on polygons,
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circles, and other points, such as "point is in polygon". Previously
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indexing only worked for bounding boxes. This should make many
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indexing only worked for bounding boxes. This should make many
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PostGIS queries faster.
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</para>
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</listitem>
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@ -1688,21 +1711,30 @@
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<listitem>
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<para>
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Install server-side language PL/pgSQL by default (Bruce Momjian)
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Install PL/pgSQL by default (Bruce Momjian)
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</para>
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</listitem>
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<listitem>
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<para>
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Allow PL/pgSQL to handle row types with dropped columns (Pavel Stehule)
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Improve PL/pgSQL's ability to handle row types with dropped columns
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(Pavel Stehule)
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</para>
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</listitem>
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<listitem>
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<para>
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Allow <literal>IN</> parameters to be assigned values within
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Allow input parameters to be assigned values within
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PL/pgSQL functions (Steve Prentice)
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</para>
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<para>
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Formerly, input parameters were treated as being declared
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<literal>CONST</>. This restriction has been removed to simplify
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porting of functions from other DBMSes that do not impose the
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equivalent restriction. An input parameter now acts like a local
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variable initialized to the passed-in value.
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</para>
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</listitem>
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<listitem>
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@ -1713,21 +1745,19 @@
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<listitem>
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<para>
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Have PL/pgSQL use the main lexer, rather than a custom version (Tom Lane)
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Make PL/pgSQL use the main lexer, rather than its own version
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(Tom Lane)
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</para>
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<para>
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This ensures accurate tracking of the main system's behavior for details
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such as string escaping.
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</para>
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</listitem>
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</itemizedlist>
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</sect4>
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<sect4>
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<title><link linkend="plpgsql-cursors">PL/pgSQL Cursors</link></title>
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<itemizedlist>
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<listitem>
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<para>
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Add count and <literal>ALL</> options to <command>MOVE
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Add <replaceable>count</> and <literal>ALL</> options to <command>MOVE
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FORWARD</>/<literal>BACKWARD</> in PL/pgSQL (Pavel Stehule)
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</para>
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</listitem>
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@ -1741,8 +1771,8 @@
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<listitem>
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<para>
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Add PL/pgSQL's <command>OPEN cursor FOR EXECUTE</> to use parameters
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(Pavel Stehule, Itagaki Takahiro)
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Allow PL/pgSQL's <command>OPEN <replaceable>cursor</> FOR EXECUTE</> to
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use parameters (Pavel Stehule, Itagaki Takahiro)
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</para>
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<para>
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@ -2482,7 +2512,7 @@
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<listitem>
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<para>
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Enable the server lexer to be reentrant (Tom Lane)
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Enable the server's lexer to be reentrant (Tom Lane)
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</para>
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<para>
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@ -2796,9 +2826,8 @@
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</para>
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<para>
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This filter dictionary removes accents from tokens, and
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makes full-text searches over multiple languages much
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easier.
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This filter dictionary removes accents from letters, which
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makes full-text searches over multiple languages much easier.
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</para>
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</listitem>
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Reference in New Issue