postgresql/doc/src/sgml/release-8.4.sgml

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 <sect1 id="release-8-4">
  <title>Release 8.4</title>

  <note>
   <title>Release date</title>
   <simpara>2009-??-??, ITEMS CURRENT AS OF 2009-04-08</simpara>
  </note>

  <sect2>
   <title>Overview</title>

   <para>
    After many years of development, <productname>PostgreSQL</> has
    become feature-complete in many areas.   This release shows a
    targeted approach to adding features (e.g., authentication,
    monitoring, space reuse), and adds capabilities defined in the
    later SQL standards.  The major areas of enhancement are:
   </para>

   <itemizedlist>

    <!-- This list duplicates items below, but without authors or details-->

    <listitem>
     <para>
      Windowing Functions
     </para>
    </listitem>

    <listitem>
     <para>
      Common Table Expressions and Recursive Joins
     </para>
    </listitem>

    <listitem>
     <para>
      Default and variadic parameters for functions
     </para>
    </listitem>

    <listitem>
     <para>
      Parallel Restore
     </para>
    </listitem>

    <listitem>
     <para>
      Column Permissions
     </para>
    </listitem>

    <listitem>
     <para>
      Per-database locale settings
     </para>
    </listitem>

    <listitem>
     <para>
      Improved hash indexes
     </para>
    </listitem>

    <listitem>
     <para>
      Improved join performance for <literal>EXISTS</> and <literal>NOT EXISTS</> queries
     </para>
    </listitem>

    <listitem>
     <para>
      Easier-to-use Warm Standby
     </para>
    </listitem>

    <listitem>
     <para>
      Automatic sizing of the Free Space Map
     </para>
    </listitem>

    <listitem>
     <para>
      Visibility Map (greatly reduces vacuum overhead for slowly-changing tables)
     </para>
    </listitem>

    <listitem>
     <para>
      Version-aware psql (backslash commands work against older servers)
     </para>
    </listitem>

    <listitem>
     <para>
      Support SSL certificates for user authentication
     </para>
    </listitem>

    <listitem>
     <para>
      Per-function runtime statistics
     </para>
    </listitem>

    <listitem>
     <para>
      Easy editing of functions in psql
     </para>
    </listitem>

    <listitem>
     <para>
      New contrib modules: pg_stat_statements, auto_explain, citext, btree_gin
     </para>
    </listitem>

   </itemizedlist>

   <para>
    The above items are explained in more detail in the sections below.
   </para>

  </sect2>

  <sect2>
   <title>Migration to Version 8.4</title>

   <para>
    A dump/restore using <application>pg_dump</application> is
    required for those wishing to migrate data from any previous
    release.
   </para>

   <para>
    Observe the following incompatibilities:
   </para>

   <sect3>
    <title>General</title>
    <itemizedlist>

     <listitem>
      <para>
       Use 64-bit integer datetimes by default (Neil Conway)
      </para>

      <para>
       Previously this was selected by <application>configure</>'s
       <option>--enable-integer-datetimes</> option.  To retain
       the old behavior, build with <option>--disable-integer-datetimes</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <application>ipcclean</> utility command (Bruce)
      </para>

      <para>
       The utility only worked on a few platforms.  Users should use
       their operating system tools instead.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Server Settings</title>
    <itemizedlist>

     <listitem>
      <para>
       Change default setting for
       <literal>log_min_messages</> to <literal>warning</> (previously
       it was <literal>notice</>) to reduce log file volume (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <literal>debug_print_parse</>, <literal>debug_print_rewritten</>,
       and <literal>debug_print_plan</>
       output appear at <literal>LOG</> message level, not
       <literal>DEBUG1</> as formerly (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <literal>debug_pretty_print</> default to <literal>on</> (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <varname>explain_pretty_print</> parameter (no longer needed) (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <varname>log_temp_files</> settable by superusers only, like other
       logging options (Simon Riggs)
      </para>
     </listitem>

     <listitem>
      <para>
       Remove automatic appending of the epoch timestamp when no <literal>%</>
       escapes are present in <literal>log_filename</> (Robert Haas)
      </para>

      <para>
       This change was made because some users wanted a fixed log filename,
       for use with an external log rotation tool.
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <varname>log_restartpoints</> from <filename>recovery.conf</>;
       instead use <varname>log_checkpoints</> (Simon)
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <varname>krb_realm</> and <varname>krb_server_hostname</>;
       these are now set in <filename>pg_hba.conf</> instead (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       There are also significant changes in <link
       linkend="release-8-4-pg-hba-conf"><filename>pg_hba.conf</></link>,
       as described below.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Queries</title>

    <itemizedlist>

     <listitem>
      <para>
       Change <command>TRUNCATE</> and <command>LOCK</> to
       apply to child tables of the specified table(s) (Peter)
      </para>

      <para>
       These commands now accept an <literal>ONLY</> option that prevents
       processing child tables; this option must be used if the old
       behavior is needed.
      </para>
     </listitem>

     <listitem>
      <para>
       <command>SELECT DISTINCT</> and
       <literal>UNION</>/<literal>INTERSECT</>/<literal>EXCEPT</>
       no longer always produce sorted output (Tom)
      </para>

      <para>
       Previously, these types of queries always removed duplicate rows
       by means of Sort/Unique processing (i.e., sort then remove adjacent
       duplicates).  Now they can be implemented by hashing, which will not
       produce sorted output.  If an application relied on the output being
       in sorted order, the recommended fix is to add an <literal>ORDER BY</>
       clause.  As a short-term workaround, the previous behavior can be
       restored by disabling <literal>enable_hashagg</>, but that is a very
       performance-expensive fix.  <literal>SELECT DISTINCT ON</> never uses
       hashing, however, so its behavior is unchanged.
      </para>
     </listitem>

     <listitem>
      <para>
       Force child tables to inherit <literal>CHECK</> constraints from parents
       (Alex Hunsaker, Nikhil Sontakke, Tom)
      </para>

      <para>
       Formerly it was possible to drop such a constraint from a child
       table, allowing rows that violate the constraint to be visible
       when scanning the parent table.  This was deemed inconsistent,
       as well as contrary to SQL standard.
      </para>
     </listitem>

     <listitem>
      <para>
       Disallow negative <literal>LIMIT</> or <literal>OFFSET</>
       values, rather than treating them as zero (Simon)
      </para>
     </listitem>

     <listitem>
      <para>
       Disallow <command>LOCK TABLE</> outside a transaction block
       (Tom)
      </para>

      <para>
       Such an operation is useless because the lock would be released
       immediately.
      </para>
     </listitem>

     <listitem>
      <para>
       Sequences now contain an additional <structfield>start_value</> column
       (Zoltan Boszormenyi)
      </para>

      <para>
       This supports <command>ALTER SEQUENCE ... RESTART</>.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>


   <sect3>
    <title>Functions and Operators</title>

    <itemizedlist>

     <listitem>
      <para>
       Make <type>numeric</> zero raised to a fractional power return
       <literal>0</>, rather than throwing an error, and make
       <type>numeric</> zero raised to the zero power return <literal>1</>,
       rather than error (Bruce)
      </para>

      <para>
       This matches the longstanding <type>float8</> behavior.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow unary minus of floating-point values to produce minus zero (Tom)
      </para>

      <para>
       The changed behavior is more <acronym>IEEE</>-standard
       compliant.
      </para>
     </listitem>

     <listitem>
      <para>
       Throw an error if an escape character is the last character in
       a <literal>LIKE</> pattern (i.e., it has nothing to escape) (Tom)
      </para>

      <para>
       Previously, such an escape character was silently ignored,
       thus possibly masking application logic errors.
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <literal>~=~</> and <literal>~&lt;&gt;~</> operators
       formerly used for <literal>LIKE</> index comparisons (Tom)
      </para>

      <para>
       Pattern indexes now use the regular equality operator.
      </para>
     </listitem>

     <listitem>
      <para>
       <function>xpath()</> now passes its arguments to <application>libxml</>
       without any changes (Andrew)
      </para>

      <para>
       This means that the XML argument must be a well-formed XML document.
       The previous coding attempted to allow XML fragments, but it did not
       work well.
      </para>
     </listitem>

     <listitem>
      <para>
       Make <function>xmlelement()</> format attribute values just like
       content values (Peter)
      </para>

      <para>
       Previously, attribute values were formatted according to the
       normal SQL output behavior, which is sometimes at odds with
       XML rules.
      </para>
     </listitem>

     <listitem>
      <para>
       Adopt a faster algorithm for hash functions (Kenneth Marshall,
       based on work of Bob Jenkins)
      </para>

      <para>
       Many of the built-in hash functions now deliver different results on
       little-endian and big-endian platforms.
      </para>
     </listitem>

    </itemizedlist>

    <sect4>
     <title>Temporal Functions and Operators</title>

     <itemizedlist>

      <listitem>
       <para>
        <varname>DateStyle</> no longer controls <type>interval</> output
        formatting; instead there is a new variable <varname>IntervalStyle</>
        (Ron Mayer)
       </para>
      </listitem>

      <listitem>
       <para>
        Improve consistency of handling of fractional seconds in
        <type>timestamp</> and <type>interval</> output (Ron Mayer)
       </para>

       <para>
        This may result in displaying a different number of fractional
        digits than before, or rounding instead of truncating.
       </para>
      </listitem>

      <listitem>
       <para>
        Make <function>to_char()</>'s localized month/day names depend
        on <varname>LC_TIME</>, not <varname>LC_MESSAGES</> (Euler
        Taveira de Oliveira)
       </para>
      </listitem>

      <listitem>
       <para>
        Cause <function>to_date()</> and <function>to_timestamp()</>
        to more consistently report errors for invalid input (Brendan
        Jurd)
       </para>

       <para>
        Previous versions would often ignore or silently misread input
        that did not match the format string.  Such cases will now
        result in an error.
       </para>
      </listitem>

      <listitem>
       <para>
        Fix <function>to_timestamp()</> to not require upper/lower case
        matching for meridian (<literal>AM</>/<literal>PM</>) and era
        (<literal>BC</>/<literal>AD</>) format designations  (Brendan
        Jurd)
       </para>

       <para>
        For example, input value <literal>ad</> now matches the format
        string <literal>AD</>.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

   </sect3>

  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    Below you will find a detailed account of the changes between
    <productname>PostgreSQL</productname> 8.4 and the previous major
    release.
   </para>

   <sect3>
    <title>Performance</title>
    <itemizedlist>

     <listitem>
      <para>
       Improve optimizer statistics calculations (Jan Urbanski, Tom)
      </para>

      <para>
       In particular, estimates for full-text-search operators are
       greatly improved.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <command>SELECT DISTINCT</> and
       <literal>UNION</>/<literal>INTERSECT</>/<literal>EXCEPT</> to
       use hashing (Tom)
      </para>

      <para>
       This means that these types of queries no longer automatically
       produce sorted output.
      </para>
     </listitem>

     <listitem>
      <para>
       Create explicit concepts of semi-joins and anti-joins (Tom)
      </para>

      <para>
       This work formalizes our previous ad-hoc treatment of <literal>IN
       (SELECT ...)</> clauses, and extends it to <literal>EXISTS</> and
       <literal>NOT EXISTS</> clauses.  It should result in significantly
       better planning of <literal>EXISTS</> and <literal>NOT EXISTS</>
       queries.  In general, logically equivalent <literal>IN</> and
       <literal>EXISTS</> clauses should now have similar performance,
       whereas previously <literal>IN</> often won.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve optimization of sub-selects beneath outer joins (Tom)
      </para>

      <para>
       Formerly, a sub-select or view could not be optimized very well if it
       appeared within the nullable side of an outer join and contained
       non-strict expressions (for instance, constants) in its result list.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve the performance of <function>text_position()</> and
       related functions by using Boyer-Moore-Horspool searching (David
       Rowley)
      </para>

      <para>
       This is particularly helpful for long search patterns.
      </para>
     </listitem>

     <listitem>
      <para>
       Reduce I/O load of writing the statistics collection file
       by writing the file only when requested (Martin Pihlak)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve performance for bulk inserts (Robert Haas, Simon)
      </para>
     </listitem>

     <listitem>
      <para>
       Increase the default value of <varname>default_statistics_target</>
       from <literal>10</> to <literal>100</> (Greg Sabino Mullane,
       Tom)
      </para>

      <para>
       The maximum value was also increased from <literal>1000</> to
       <literal>10000</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Perform <varname>constraint_exclusion</> checking by default
       in queries involving inheritance or <literal>UNION ALL</> (Tom)
      </para>

      <para>
       A new <varname>constraint_exclusion</> setting,
       <literal>partition</>, was added to specify this behavior.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow I/O read-ahead for bitmap index scans (Greg Stark)
      </para>

      <para>
       The amount of read-ahead is controlled by
       <varname>effective_io_concurrency</>.  This feature is available only
       if the kernel has <function>posix_fadvise()</> support.
      </para>
     </listitem>

     <listitem>
      <para>
       Inline simple set-returning <acronym>SQL</> functions in
       <literal>FROM</> clauses (Richard Rowell)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve performance of multi-batch hash joins by providing a special
       case for join key values that are especially common in the outer
       relation (Bryce Cutt, Ramon Lawrence)
      </para>
     </listitem>

     <listitem>
      <para>
       Reduce volume of temporary data in multi-batch hash joins
       by suppressing <quote>physical tlist</> optimization (Michael
       Henderson, Ramon Lawrence)
      </para>
     </listitem>

     <listitem>
      <para>
       Avoid waiting for idle-in-transaction sessions during
       <command>CREATE INDEX CONCURRENTLY</> (Simon)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve performance of shared cache invalidation (Tom)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Server</title>

    <sect4>
     <title>Settings</title>

     <itemizedlist>

      <listitem>
       <para>
        Convert many <filename>postgresql.conf</> settings to enumerated
        values so that <literal>pg_settings</> can display the valid
        values (Magnus)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <varname>cursor_tuple_fraction</> parameter to control the
        fraction of a cursor's rows that the planner assumes will be
        fetched (Robert Hell)
       </para>
      </listitem>

      <listitem>
       <para>
        Allow underscores in the names of custom variable
        classes in <filename>postgresql.conf</> (Tom)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Authentication and security</title>
     <itemizedlist>

      <listitem>
       <para>
        Report appropriate error message for combination of <literal>MD5</>
        authentication and <varname>db_user_namespace</> enabled (Bruce)
       </para>
      </listitem>

      <listitem>
       <para>
        Remove support for the (insecure) <literal>crypt</> authentication method
        (Magnus)
       </para>

       <para>
        This effectively obsoletes pre-<productname>PostgreSQL</> 7.2 client
        libraries, as there is no longer any non-plaintext password method that
        they can use.
       </para>
      </listitem>

      <listitem>
       <para>
        Support regular expressions in <filename>pg_ident.conf</>
        (Magnus)
       </para>
      </listitem>

      <listitem>
       <para>
        Allow <productname>Kerberos</>/<acronym>GSSAPI</> parameters
        to be changed without restarting the postmaster (Magnus)
       </para>
      </listitem>

      <listitem>
       <para>
        Support <acronym>SSL</> certificate chains in server certificate
        file (Andrew Gierth)
       </para>

       <para>
        Including the full certificate chain makes the client able
        to verify the certificate without having all intermediate CA
        certificates present in the local store, which is often the case for
        commercial CAs.
       </para>
      </listitem>
     </itemizedlist>

    </sect4>

    <sect4 id="release-8-4-pg-hba-conf">
     <title><filename>pg_hba.conf</></title>
     <itemizedlist>

      <listitem>
       <para>
        Parse <filename>pg_hba.conf</> fully when it is loaded,
        so that errors are reported immediately (Magnus)
       </para>

       <para>
        Previously, most errors in the file wouldn't be detected until clients
        tried to connect, so an erroneous file could render the system
        unusable.  With the new behavior, if an error is detected during
        reload then the bad file is rejected and the postmaster continues
        to use its old copy.
       </para>
      </listitem>

      <listitem>
       <para>
        Show all parsing errors in <filename>pg_hba.conf</> instead of
        aborting after the first one (Selena Deckelmann)
       </para>
      </listitem>

      <listitem>
       <para>
        Remove the <literal>ident sameuser</> option, instead making that
        behavior the default if no usermap is specified (Magnus)
       </para>
      </listitem>

      <listitem>
       <para>
        Change all authentication options to use <literal>name=value</>
        syntax (Magnus)
       </para>

       <para>
        This makes incompatible changes to the <literal>ldap</>,
        <literal>pam</> and <literal>ident</> authentication methods. All
        <filename>pg_hba.conf</> entries with these methods need to be
        rewritten using the new format.
       </para>
      </listitem>

      <listitem>
       <para>
        Allow a usermap parameter for all external authentication methods
        (Magnus)
       </para>

       <para>
        Previously a usermap was only supported for <literal>ident</>
        authentication.
       </para>
      </listitem>

      <listitem>
       <para>
        Add <literal>clientcert</> option to control requesting of a
        client certificate (Magnus)
       </para>

       <para>
        Previously this was controlled by the presence of a root
        certificate file in the server's data directory.
       </para>
      </listitem>

      <listitem>
       <para>
        Add <literal>cert</> authentication method to allow
        <emphasis>user</> authentication via <acronym>SSL</> certificates
        (Magnus)
       </para>

       <para>
        Previously <acronym>SSL</> certificates could only verify that
        the client had access to a certificate, not authenticate a
        user.
       </para>
      </listitem>

      <listitem>
       <para>
        Allow <literal>krb5</>, <literal>gssapi</> and <literal>sspi</>
        realm and <literal>krb5</> host settings to be specified in
        <filename>pg_hba.conf</> (Magnus)
       </para>

       <para>
        These override the settings in <filename>postgresql.conf</>.
       </para>
      </listitem>

      <listitem>
       <para>
        Add <varname>include_realm</> parameter for <literal>krb5</>,
        <literal>gssapi</>, and <literal>sspi</> methods (Magnus)
       </para>

       <para>
        This allows identical usernames from different realms to be
        authenticated as different database users using usermaps.
       </para>
      </listitem>

      <listitem>
       <para>
        Support <literal>ident</> authentication over Unix-domain sockets
        on <productname>Solaris</> (Garick Hamlin)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Continuous Archiving</title>
     <itemizedlist>

      <listitem>
       <para>
        Provide an option to <function>pg_start_backup()</> to force its
        implied checkpoint to finish as quickly as possible (Tom)
       </para>

       <para>
        The default behavior avoids excess I/O consumption, but that is
        pointless if no concurrent query activity is going on.
       </para>
      </listitem>

      <listitem>
       <para>
        Make <function>pg_stop_backup()</> wait for modified <acronym>WAL</>
        files to be archived (Simon)
       </para>

       <para>
        This guarantees that the backup is valid at the time
        <function>pg_stop_backup()</> completes.
       </para>
      </listitem>

      <listitem>
       <para>
        Delay <quote>smart</> shutdown while a continuous archiving base backup
        is in progress (Laurenz Albe)
       </para>
      </listitem>

      <listitem>
       <para>
        Cancel a continuous archiving base backup if <quote>fast</> shutdown
        is requested (Laurenz Albe)
       </para>
      </listitem>

      <listitem>
       <para>
        Allow <filename>recovery.conf</> boolean variables to take the
        same range of string values as <filename>postgresql.conf</>
        boolean variables
        (Bruce)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Monitoring</title>
     <itemizedlist>

      <listitem>
       <para>
        Add <function>pg_conf_load_time()</> to report when
        the <productname>PostgreSQL</> configuration files were last loaded
        (George Gensure)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <function>pg_terminate_backend()</> to safely terminate a
        backend (the <literal>SIGTERM</> signal works also) (Tom, Bruce)
       </para>

       <para>
        While it's always been possible to <literal>SIGTERM</> a single
        backend, this was previously considered unsupported; and testing
        of the case found some bugs that are now fixed.
       </para>
      </listitem>

      <listitem>
       <para>
        Add ability to track user-defined functions' call counts and
        runtimes (Martin Pihlak)
       </para>

       <para>
        Function statistics appear in a new system view,
        <literal>pg_stat_user_functions</>.  Tracking is controlled
        by the new parameter <varname>track_functions</>.
       </para>
      </listitem>

      <listitem>
       <para>
        Allow specification of the maximum query string size in
        <literal>pg_stat_activity</> via new
        <varname>track_activity_query_size</> parameter (Thomas Lee)
       </para>
      </listitem>

      <listitem>
       <para>
        Increase the maximum line length sent to <application>syslog</>, in
        hopes of improving performance (Tom)
       </para>
      </listitem>

      <listitem>
       <para>
        Add read-only configuration variables <varname>segment_size</>,
        <varname>wal_block_size</>, and <varname>wal_segment_size</>
        (Bernd Helmle)
       </para>
      </listitem>

      <listitem>
       <para>
        When reporting a deadlock, report the text of all queries involved
        in the deadlock to the server log  (Itagaki Takahiro)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <function>pg_stat_get_activity(pid)</> function to return
        information about a specific process id (Magnus)
       </para>
      </listitem>

      <listitem>
       <para>
        Allow the location of the server's statistics file to be specified
        via <varname>stats_temp_directory</> (Magnus)
       </para>

       <para>
        This allows the statistics file to be placed in a
        <acronym>RAM</>-resident directory to reduce I/O requirements.
        On startup/shutdown, the file is copied to its traditional location
        (<literal>$PGDATA/global/</>) so it is preserved across restarts.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

   </sect3>

   <sect3>
    <title>Queries</title>
    <itemizedlist>

     <listitem>
      <para>
       Add support for <literal>WINDOW</> functions (Hitoshi Harada)
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for <literal>WITH</> clauses (CTEs), including <literal>WITH
       RECURSIVE</> (Yoshiyuki Asaba, Tatsuo Ishii, Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <command>TABLE</> command (Peter)
      </para>

      <para>
       <literal>TABLE tablename</> is a SQL standard short-hand for
       <literal>SELECT * FROM tablename</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <literal>AS</> to be optional when specifying a
       <command>SELECT</> (or <literal>RETURNING</>) column output
       label (Hiroshi Saito)
      </para>

      <para>
       This works so long as the column label is not any
       <productname>PostgreSQL</> keyword; otherwise <literal>AS</> is still
       needed.
      </para>
     </listitem>

     <listitem>
      <para>
       Support set-returning functions in <command>SELECT</> result lists
       even for functions that return their result via a tuplestore (Tom)
      </para>

      <para>
       In particular, this means that functions written in PL/PgSQL
       and other PL languages can now be called this way.
      </para>
     </listitem>

     <listitem>
      <para>
       Support set-returning functions in the output of aggregation
       and grouping queries (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <command>SELECT FOR UPDATE</>/<literal>SHARE</> to work
       on inheritance trees (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add infrastructure for <acronym>SQL/MED</> (Martin Pihlak,
       Peter)
      </para>

      <para>
       There are no remote or external <acronym>SQL/MED</> capabilities
       yet, but this change provides a standardized and future-proof
       system for managing connection information for modules like
       <filename>dblink</> and <filename>plproxy</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Invalidate cached plans when referenced schemas, functions, operators,
       or operator classes are modified (Martin Pihlak, Tom)
      </para>

      <para>
       This improves the system's ability to respond to on-the-fly
       DDL changes.
      </para>
     </listitem>
     <listitem>
      <para>
       Allow comparison of composite types and allow arrays of
       anonymous composite types (Tom)
      </para>

      <para>
       This allows constructs such as
       <literal>row(1, 1.1) = any (array[row(7, 7.7), row(1, 1.0)])</>.
       This is particularly useful in recursive queries.
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for Unicode string literal and identifier specifications
       using code points, e.g. <literal>U&amp;'d\0061t\+000061'</>
       (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve the parser's ability to report error locations (Tom)
      </para>

      <para>
       An error location is now reported for many semantic errors,
       such as mismatched datatypes, that previously could not be localized.
      </para>
     </listitem>

    </itemizedlist>

    <sect4>
     <title><command>TRUNCATE</></title>
     <itemizedlist>

      <listitem>
       <para>
        Support statement-level <literal>ON TRUNCATE</> triggers (Simon)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <literal>RESTART</>/<literal>CONTINUE IDENTITY</> options
        for <command>TRUNCATE TABLE</>
        (Zoltan Boszormenyi)
       </para>

       <para>
        The start value of a sequence can be changed by <command>ALTER
        SEQUENCE START WITH</>.
       </para>
      </listitem>

      <listitem>
       <para>
        Allow <command>TRUNCATE tab1, tab1</> to succeed (Bruce)
       </para>
      </listitem>

      <listitem>
       <para>
        Add a separate <command>TRUNCATE</> permission (Robert Haas)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title><command>EXPLAIN</></title>
     <itemizedlist>

      <listitem>
       <para>
        Make <command>EXPLAIN VERBOSE</> show the output columns of each
        plan node (Tom)
       </para>

       <para>
        Previously <command>EXPLAIN VERBOSE</> output an internal
        representation of the query plan.  (That behavior is now
        available via <varname>debug_print_plan</>.)
       </para>
      </listitem>

      <listitem>
       <para>
        Make <command>EXPLAIN</> identify subplans and initplans with
        individual labels (Tom)
       </para>
      </listitem>

      <listitem>
       <para>
        Make <command>EXPLAIN</> honor <varname>debug_print_plan</> (Tom)
       </para>
      </listitem>

      <listitem>
       <para>
        Allow <command>EXPLAIN</> on <command>CREATE TABLE AS</> (Peter)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title><literal>LIMIT</>/<literal>OFFSET</></title>
     <itemizedlist>

      <listitem>
       <para>
        Allow sub-selects in <literal>LIMIT</> and <literal>OFFSET</> (Tom)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <acronym>SQL</>-standard syntax for
        <literal>LIMIT</>/<literal>OFFSET</> capabilities (Peter)
       </para>

       <para>
        To wit,
        <literal>OFFSET num {ROW|ROWS} FETCH {FIRST|NEXT} [num] {ROW|ROWS}
        ONLY</>.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

   </sect3>

   <sect3>
    <title>Object Manipulation</title>
    <itemizedlist>

     <listitem>
      <para>
       Add support for column-level privileges (Stephen Frost, KaiGai
       Kohei)
      </para>
     </listitem>

     <listitem>
      <para>
       Refactor multi-object <command>DROP</> operations to reduce the
       need for <literal>CASCADE</> (Alex Hunsaker)
      </para>

      <para>
       For example, if table <literal>B</> has a dependency on table
       <literal>A</>, the command <literal>DROP TABLE A, B</> no longer
       requires the <literal>CASCADE</> option.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix various problems with concurrent <command>DROP</> commands
       by ensuring that locks are taken before we begin to drop dependencies
       of an object (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve reporting of dependencies during <command>DROP</>
       commands (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <literal>WITH [NO] DATA</> clause to <command>CREATE TABLE
       AS</>, per the <acronym>SQL</> standard (Peter, Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for user-defined I/O conversion casts (Heikki)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <command>CREATE AGGREGATE</> to use an <type>internal</>
       transition datatype (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <literal>LIKE</> clause to <command>CREATE TYPE</> (Tom)
      </para>

      <para>
       This simplifies creation of data types that use the same internal
       representation as an existing type.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow specification of the type category and <quote>preferred</>
       status for user-defined base types (Tom)
      </para>

      <para>
       This allows more control over the coercion behavior of user-defined
       types.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <command>CREATE OR REPLACE VIEW</> to add columns to the
       end of a view (Robert Haas)
      </para>
     </listitem>

    </itemizedlist>

    <sect4>
     <title><command>ALTER</></title>
     <itemizedlist>

      <listitem>
       <para>
        Add <command>ALTER TYPE RENAME</> (Petr Jelinek)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <command>ALTER SEQUENCE ... RESTART</> (with no parameter) to
        reset a sequence to its initial value (Zoltan Boszormenyi)
       </para>
      </listitem>

      <listitem>
       <para>
        Modify the <command>ALTER TABLE</> syntax to allow all reasonable
        combinations for tables, indexes, sequences, and views (Tom)
       </para>

       <para>
        This change allows the following new syntaxes:

        <itemizedlist>
         <listitem>
          <para>
           <command>ALTER SEQUENCE OWNER TO</>
          </para>
         </listitem>
         <listitem>
          <para>
           <command>ALTER VIEW ALTER COLUMN SET/DROP DEFAULT</>
          </para>
         </listitem>
         <listitem>
          <para>
           <command>ALTER VIEW OWNER TO</>
          </para>
         </listitem>
         <listitem>
          <para>
           <command>ALTER VIEW SET SCHEMA</>
          </para>
         </listitem>
        </itemizedlist>

        There is no actual new functionality here, but formerly
        you had to say <command>ALTER TABLE</> to do these things,
        which was confusing.
       </para>
      </listitem>

      <listitem>
       <para>
        Add support for the syntax <command>ALTER TABLE ... ALTER COLUMN
        ... SET DATA TYPE</> (Peter)
       </para>

       <para>
        This is <acronym>SQL</>-standard syntax for functionality that
        was already supported.
       </para>
      </listitem>

      <listitem>
       <para>
        Make <command>ALTER TABLE SET WITHOUT OIDS</> rewrite the table
        to physically remove <type>OID</> values (Tom)
       </para>

       <para>
        Also, add <command>ALTER TABLE SET WITH OIDS</> to rewrite the
        table to add <type>OID</>s.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Database Manipulation</title>
     <itemizedlist>

      <listitem>
       <para>
        Improve reporting of
        <command>CREATE</>/<command>DROP</>/<command>RENAME DATABASE</>
        failure when uncommitted prepared transactions are the cause
        (Tom)
       </para>
      </listitem>

      <listitem>
       <para>
        Make <varname>LC_COLLATE</> and <varname>LC_CTYPE</> into
        per-database settings (Radek Strnad, Heikki)
       </para>

       <para>
        This makes collation similar to encoding, which was always
        configurable per database.
       </para>
      </listitem>

      <listitem>
       <para>
        Improve checks that the database encoding, collation
        (<varname>LC_COLLATE</>), and character classes
        (<varname>LC_CTYPE</>) match (Heikki)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <command>ALTER DATABASE SET TABLESPACE</> to move a database
        to a new tablespace (Guillaume Lelarge, Bernd Helmle)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

   </sect3>

   <sect3>
    <title>Utility Operations</title>

    <itemizedlist>

     <listitem>
      <para>
       Add a <literal>VERBOSE</> option to the <command>CLUSTER</> command and
       <application>clusterdb</> (Jim Cox)
      </para>
     </listitem>

     <listitem>
      <para>
       Decrease memory requirements for recording pending trigger
       events (Tom)
      </para>
     </listitem>

    </itemizedlist>

    <sect4>
     <title>Indexes</title>
     <itemizedlist>

      <listitem>
       <para>
        Dramatically improve the speed of building and accessing hash
        indexes (Tom Raney, Shreya Bhargava)
       </para>

       <para>
        This allows hash indexes to be sometimes faster than btree
        indexes.  However, hash indexes are still not crash-safe.
       </para>
      </listitem>

      <listitem>
       <para>
        Make hash indexes store only the hash code, not the full value of
        the indexed column (Xiao Meng)
       </para>

       <para>
        This greatly reduces the size of hash indexes for long indexed
        values, improving performance.
       </para>
      </listitem>

      <listitem>
       <para>
        Implement fast update option for GIN indexes (Teodor, Oleg)
       </para>

       <para>
        This option greatly improves update speed at a small penalty in search
        speed.
       </para>
      </listitem>

      <listitem>
       <para>
        <literal>xxx_pattern_ops</> indexes can now be used for simple
        equality comparisons, not only for <literal>LIKE</> (Tom)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Full Text Indexes</title>
     <itemizedlist>

      <listitem>
       <para>
        Remove the requirement to use <literal>@@@</> when doing
        <acronym>GIN</> weighted lookups on full text indexes (Tom, Teodor)
       </para>

       <para>
        The normal <literal>@@</> text search operator can be used
        instead.
       </para>
      </listitem>

      <listitem>
       <para>
        Add an optimizer selectivity function for <literal>@@</> text
        search operations (Jan Urbanski)
       </para>
      </listitem>

      <listitem>
       <para>
        Allow prefix matching in full text searches (Teodor Sigaev,
        Oleg Bartunov)
       </para>
      </listitem>

      <listitem>
       <para>
        Support multi-column <acronym>GIN</> indexes (Teodor Sigaev)
       </para>
      </listitem>

      <listitem>
       <para>
        Improve support for Nepali language and Devanagari alphabet (Teodor)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title><command>VACUUM</></title>
     <itemizedlist>

      <listitem>
       <para>
        Track free space in separate per-relation <quote>fork</> files (Heikki)
       </para>

       <para>
        Free space discovered by <command>VACUUM</> is now recorded in
        <filename>*_fsm</> files, rather than in a fixed-sized shared memory
        area.  The <varname>max_fsm_pages</> and <varname>max_fsm_relations</>
        settings have been removed, greatly simplifying administration of
        free space management.
       </para>
      </listitem>

      <listitem>
       <para>
        Add a visibility map to track pages that do not require
        vacuuming (Heikki)
       </para>

       <para>
        This allows <command>VACUUM</> to avoid scanning all of
        a table when only a portion of the table needs vacuuming.
        The visibility map is stored in per-relation <quote>fork</> files.
       </para>
      </listitem>

      <listitem>
       <para>
        Add <varname>vacuum_freeze_table_age</> parameter to control
        when <command>VACUUM</> should ignore the visibility map and
        do a full table scan to freeze tuples (Heikki)
       </para>
      </listitem>

      <listitem>
       <para>
        Track transaction snapshots more carefully (Alvaro)
       </para>

       <para>
        This improves <command>VACUUM</>'s ability to reclaim space
        in the presence of long-running transactions.
       </para>
      </listitem>

      <listitem>
       <para>
        Add ability to specify per-relation autovacuum and <acronym>TOAST</>
        parameters in <command>CREATE TABLE</> (Alvaro, Euler Taveira de
        Oliveira)
       </para>

       <para>
        Autovacuum options used to be stored in a system table.
       </para>
      </listitem>

      <listitem>
       <para>
        Add <literal>--freeze</> option to <application>vacuumdb</>
        (Bruce)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

   </sect3>

   <sect3>
    <title>Data Types</title>
    <itemizedlist>

     <listitem>
      <para>
       Add a <literal>CaseSensitive</> option for text search synonym
       dictionaries (Simon)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve the precision of <type>NUMERIC</> division (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add basic arithmetic operators for <type>int2</> with <type>int8</>
       (Tom)
      </para>

      <para>
       This eliminates the need for explicit casting in some situations.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <type>UUID</> input to accept an optional hyphen after
       every fourth digit (Robert Haas)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <literal>on</>/<literal>off</> as input for the boolean data type
       (Itagaki Takahiro)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow spaces around <literal>NaN</> in the input string for
       type <type>numeric</> (Sam Mason)
      </para>
     </listitem>

    </itemizedlist>

    <sect4>
     <title>Temporal Data Types</title>
     <itemizedlist>

      <listitem>
       <para>
        Reject year <literal>0 BC</> and years <literal>000</> and
        <literal>0000</> (Tom)
       </para>

       <para>
        Previously these were interpreted as <literal>1 BC</>.
        (Note: years <literal>0</> and <literal>00</> are still assumed to be
        the year 2000.)
       </para>
      </listitem>

      <listitem>
       <para>
        Include <literal>SGT</> (Singapore time) in the default list of
        known time zone abbreviations (Tom)
       </para>
      </listitem>

      <listitem>
       <para>
        Support <literal>infinity</> and <literal>-infinity</> as
        values of type <type>date</> (Tom)
       </para>
      </listitem>

      <listitem>
       <para>
        Make parsing of <type>interval</> literals more standard-compliant (Tom)
       </para>

       <para>
        For example, <literal>INTERVAL '1' YEAR</> now does what it's
        supposed to.
       </para>
      </listitem>

      <listitem>
       <para>
        Allow <type>interval</> fractional-seconds precision to be specified
        after the <literal>second</> keyword, for <acronym>SQL</> standard
        compliance (Tom)
       </para>

       <para>
        Formerly the precision had to be specified after the keyword
        <type>interval</>.  (For backwards compatibility, this syntax is still
        supported, though deprecated.)  Data type definitions will now be
        output using the standard format.
       </para>
      </listitem>

      <listitem>
       <para>
        Support the <acronym>IS0 8601</> <type>interval</> syntax (Ron
        Mayer, Kevin Grittner)
       </para>

       <para>
        For example, <literal>INTERVAL 'P1Y2M3DT4H5M6.7S'</> is now
        supported.
       </para>
      </listitem>

      <listitem>
       <para>
        Add <varname>IntervalStyle</> parameter
        which controls how <type>interval</> values are output (Ron Mayer)
       </para>

       <para>
        Valid values are:  <literal>postgres</>, <literal>postgres_verbose</>,
        <literal>sql_standard</>, <literal>iso_8601</>.  This setting also
        controls the handling of negative <type>interval</> input when only
        some fields have positive/negative designations.
       </para>
      </listitem>

      <listitem>
       <para>
        Improve consistency of handling of fractional seconds in
        <type>timestamp</> and <type>interval</> output (Ron Mayer)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Arrays</title>
     <itemizedlist>

      <listitem>
       <para>
        Improve the handling of casts applied to <literal>ARRAY[]</>
        constructs, such as <literal>ARRAY[...]::integer[]</>
        (Brendan Jurd)
       </para>

       <para>
        Formerly <productname>PostgreSQL</> attempted to determine a data type
        for the <literal>ARRAY[]</> construct without reference to the ensuing
        cast.  This could fail unnecessarily in many cases, in particular when
        the <literal>ARRAY[]</> construct was empty or contained only
        ambiguous entries such as <literal>NULL</>.  Now the cast is consulted
        to determine the type that the array elements must be.
       </para>
      </listitem>

      <listitem>
       <para>
        Make <acronym>SQL</>-syntax <type>ARRAY</> dimensions optional
        to match the <acronym>SQL</> standard (Peter)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <function>array_ndims()</> to return the number
        of dimensions of an array (Robert Haas)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <function>array_length()</> to return the length
        of an array for a specified dimension (Jim Nasby, Robert
        Haas, Peter Eisentraut)
       </para>
      </listitem>

      <listitem>
       <para>
        Add aggregate function <function>array_agg()</>, which
        returns all aggregated values as a single array (Robert Haas,
        Jeff Davis, Peter)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <function>unnest()</>, which converts an array to
        individual row values (Tom)
       </para>

       <para>
        This is the opposite of <function>array_agg()</>.
       </para>
      </listitem>

      <listitem>
       <para>
        Add <function>array_fill()</> to create arrays initialized with
        a value (Pavel Stehule)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <function>generate_subscripts()</> to simplify generating
        the range of an array's subscripts (Pavel Stehule)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Wide-Value Storage (<acronym>TOAST</>)</title>
     <itemizedlist>

      <listitem>
       <para>
        Consider <acronym>TOAST</> compression on values as short as
        32 bytes (previously 256 bytes) (Greg Stark)
       </para>
      </listitem>

      <listitem>
       <para>
        Require 25% minimum space savings before using <acronym>TOAST</>
        compression (previously 20% for small values and any-savings-at-all
        for large values) (Greg)
       </para>
      </listitem>

      <listitem>
       <para>
        Improve <acronym>TOAST</> heuristics for rows that have a mix of large
        and small toastable fields, so that we prefer to push large values out
        of line and don't compress small values unnecessarily (Greg, Tom)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

   </sect3>

   <sect3>
    <title>Functions</title>
    <itemizedlist>

     <listitem>
      <para>
       Document that <function>setseed()</> allows values from
       <literal>-1</> to <literal>1</> (not just <literal>0</> to
       <literal>1</>), and enforce the valid range (Kris Jurka)
      </para>
     </listitem>

     <listitem>
      <para>
       Add server-side function <function>lo_import(filename, oid)</>
       (Tatsuo)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>quote_nullable()</>, which behaves like
       <function>quote_literal()</> but returns the string <literal>NULL</> for
       a null argument (Brendan Jurd)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve full text search <function>headline()</> function to
       allow extracting several fragments of text (Sushant Sinha)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>suppress_redundant_updates_trigger()</> trigger
       function to avoid overhead for non-data-changing updates (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>div(numeric, numeric)</> to perform <type>numeric</>
       division without rounding (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <type>timestamp</> and <type>timestamptz</> versions of
       <function>generate_series()</> (Hitoshi Harada)
      </para>
     </listitem>

    </itemizedlist>

    <sect4>
     <title>Object Information Functions</title>
     <itemizedlist>

      <listitem>
       <para>
        Implement <function>current_query()</> for use by functions
        that need to know the currently running query (Tomas Doran)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <function>pg_get_keywords()</> to return a list of the
        parser keywords (Dave Page)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <function>pg_get_functiondef()</> to see a function's
        definition (Abhijit Menon-Sen)
       </para>
      </listitem>

      <listitem>
       <para>
        Modify <function>pg_relation_size()</> to use <literal>regclass</>
        (Heikki)
       </para>

       <para>
        <function>pg_relation_size(data_type_name)</> no longer works.
       </para>
      </listitem>

      <listitem>
       <para>
        Add <literal>boot_val</> and <literal>reset_val</> columns to
        <literal>pg_settings</> output (Greg Smith)
       </para>
      </listitem>

      <listitem>
       <para>
        Add source file name and line number columns to
        <literal>pg_settings</> output for variables set in a configuration
        file (Magnus, Alvaro)
       </para>

       <para>
        For security reasons, these columns are only visible to superusers.
       </para>
      </listitem>

      <listitem>
       <para>
        Add support for <varname>CURRENT_CATALOG</>,
        <varname>CURRENT_SCHEMA</>, <varname>SET CATALOG</>, <varname>SET
        SCHEMA</> (Peter)
       </para>

       <para>
        These provide <acronym>SQL</>-standard syntax for existing features.
       </para>
      </listitem>

      <listitem>
       <para>
        Add <function>pg_typeof()</> which returns the data type
        of any value (Brendan Jurd)
       </para>
      </listitem>

      <listitem>
       <para>
        Make <function>version()</> return information about whether
        the server is a 32- or 64-bit binary (Bruce)
       </para>
      </listitem>

      <listitem>
       <para>
        Fix the behavior of information schema columns
        <literal>is_insertable_into</> and <literal>is_updatable</> to
        be consistent (Peter)
       </para>
      </listitem>

      <listitem>
       <para>
        Convert remaining builtin set-returning functions to use
        <literal>OUT</> parameters (Jaime Casanova)
       </para>

       <para>
        This makes it possible to call these functions without specifying
        a column list:  <function>pg_show_all_settings()</>,
        <function>pg_lock_status()</>, <function>pg_prepared_xact()</>,
        <function>pg_prepared_statement()</>, <function>pg_cursor()</>
       </para>
      </listitem>

      <listitem>
       <para>
        Make <function>pg_*_is_visible()</> and
        <function>has_*_privilege()</> functions return <literal>NULL</>
        for invalid OIDs, rather than reporting an error (Tom)
       </para>
      </listitem>

      <listitem>
       <para>
        Extend <function>has_*_privilege()</> functions to allow inquiring
        about the OR of multiple privileges in one call (Stephen
        Frost, Tom)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <function>has_column_privilege()</> and
        <function>has_any_column_privilege()</> functions (Stephen
        Frost, Tom)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Function Creation</title>
     <itemizedlist>

      <listitem>
       <para>
        Support variadic functions (functions with a variable number
        of arguments) (Pavel Stehule)
       </para>

       <para>
        Only trailing arguments can be optional, and they all must be
        of the same data type.
       </para>
      </listitem>

      <listitem>
       <para>
        Support default values for function arguments (Pavel Stehule)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <command>CREATE FUNCTION ... RETURNS TABLE</> clause (Pavel
        Stehule)
       </para>
      </listitem>

      <listitem>
       <para>
        Allow <acronym>SQL</>-language functions to return the output
        of an <command>INSERT</>/<command>UPDATE</>/<command>DELETE</>
        <literal>RETURNING</> clause (Tom)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>PL/PgSQL Server-Side Language</title>
     <itemizedlist>

      <listitem>
       <para>
        Support <literal>EXECUTE USING</> for easier insertion of data
        values into a dynamic query string (Pavel Stehule)
       </para>
      </listitem>

      <listitem>
       <para>
        Allow looping over the results of a cursor using a <literal>FOR</>
        loop (Pavel Stehule)
       </para>
      </listitem>

      <listitem>
       <para>
        Support <literal>RETURN QUERY EXECUTE</> (Pavel
        Stehule)
       </para>
      </listitem>

      <listitem>
       <para>
        Improve the <literal>RAISE</> command (Pavel Stehule)

        <itemizedlist>
         <listitem>
          <para>
           Support <literal>DETAIL</> and <literal>HINT</> fields
          </para>
         </listitem>
         <listitem>
          <para>
           Support specification of the <literal>SQLSTATE</> error code
          </para>
         </listitem>
         <listitem>
          <para>
           Support an exception name parameter
          </para>
         </listitem>
         <listitem>
          <para>
           Allow <literal>RAISE</> without parameters in an exception
           block to re-throw the current error
          </para>
         </listitem>
        </itemizedlist>
       </para>
      </listitem>

      <listitem>
       <para>
        Allow specification of <varname>SQLSTATE</> codes
        in <literal>EXCEPTION</> lists (Pavel Stehule)
       </para>

       <para>
        This is useful for handling custom <varname>SQLSTATE</> codes.
       </para>
      </listitem>

      <listitem>
       <para>
        Support the <literal>CASE</> statement (Pavel Stehule)
       </para>
      </listitem>

      <listitem>
       <para>
        Make <command>RETURN QUERY</> set the special <literal>FOUND</> and
        <command>GET DIAGNOSTICS</> <literal>ROW_COUNT</> variables
        (Pavel Stehule)
       </para>
      </listitem>

      <listitem>
       <para>
        Make <command>FETCH</> and <command>MOVE</> set the
        <command>GET DIAGNOSTICS</> <literal>ROW_COUNT</> variable
        (Andrew Gierth)
       </para>
      </listitem>

      <listitem>
       <para>
        Avoid memory leakage when the same function is called at varying
        exception-block nesting depths (Tom)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

   </sect3>

   <sect3>
    <title>Client Applications</title>

    <itemizedlist>

     <listitem>
      <para>
       Fix <literal>pg_ctl restart</> to preserve command-line arguments
       (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <literal>-w</>/<literal>--no-password</> option that
       prevents password prompting in all utilities that have a
       <literal>-W</>/<literal>--password</> option (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <option>-q</> (quiet) option of <application>createdb</>,
       <application>createuser</>, <application>dropdb</>,
       <application>dropuser</> (Peter)
      </para>

      <para>
       These options have had no effect since <productname>PostgreSQL</>
       8.3.
      </para>
     </listitem>

    </itemizedlist>

    <sect4>
     <title><application>psql</></title>
     <itemizedlist>

      <listitem>
       <para>
        Remove verbose startup banner; now just suggest <literal>help</>
        (Joshua Drake)
       </para>
      </listitem>

      <listitem>
       <para>
        Make <literal>help</> show common backslash commands (Greg
        Sabino Mullane)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <literal>\pset format wrapped</> mode to wrap output to the
        screen width, or file/pipe output too if <literal>\pset columns</>
        is set (Bryce Nesbitt)
       </para>
      </listitem>

      <listitem>
       <para>
        Allow all supported spellings of boolean values in <command>\pset</>,
        rather than just <literal>on</> and <literal>off</> (Bruce)
       </para>

       <para>
        Formerly, any string other than <quote>off</> was silently taken
        to mean <literal>true</>.  <application>psql</> will now complain
        about unrecognized spellings (but still take them as <literal>true</>).
       </para>
      </listitem>

      <listitem>
       <para>
        Use the pager for wide output (Bruce)
       </para>
      </listitem>

      <listitem>
       <para>
        Require a space between a one-letter backslash command and its first
        argument (Bernd Helmle)
       </para>

       <para>
        This removes a historical source of ambiguity.
       </para>
      </listitem>

      <listitem>
       <para>
        Improve tab completion support for schema-qualified and
        quoted identifiers (Greg Sabino Mullane)
       </para>
      </listitem>

      <listitem>
       <para>
        Add optional <literal>on</>/<literal>off</> argument for
        <command>\timing</> (David Fetter)
       </para>
      </listitem>

      <listitem>
       <para>
        Display access control rights on multiple lines (Brendan
        Jurd, Andreas Scherbaum)
       </para>
      </listitem>

      <listitem>
       <para>
        Make <command>\l</> show database access privileges (Andrew Gilligan)
       </para>
      </listitem>

      <listitem>
       <para>
        Make <command>\l+</> show database sizes, if permissions
        allow (Andrew Gilligan)
       </para>
      </listitem>

      <listitem>
       <para>
        Add the <command>\ef</> command to edit function definitions
        (Abhijit Menon-Sen)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title><application>psql</> \d* commands</title>

     <itemizedlist>

      <listitem>
       <para>
        Make <command>\d*</> commands that do not have a pattern argument
        show system objects only if the <literal>S</> modifier is specified
        (Greg Sabino Mullane, Bruce)
       </para>

       <para>
        The former behavior was inconsistent across different variants
        of <command>\d</>, and in most cases it provided no easy way to see
        just user objects.
       </para>
      </listitem>

      <listitem>
       <para>
        Improve <command>\d*</> commands to work with older
        <productname>PostgreSQL</> server versions (back to 7.4),
        not only the current server version
        (Guillaume Lelarge)
       </para>
      </listitem>

      <listitem>
       <para>
        Make <command>\d</> show foreign-key constraints that reference
        the selected table (Kenneth D'Souza)
       </para>
      </listitem>

      <listitem>
       <para>
        Make <command>\d</> on a sequence show its column values
        (Euler Taveira de Oliveira)
       </para>
      </listitem>

      <listitem>
       <para>
        Add column storage type and other relation options to the
        <command>\d+</> display (Gregory Stark, Euler Taveira de
        Oliveira)
       </para>
      </listitem>

      <listitem>
       <para>
        Show relation size in <command>\dt+</> output (Dickson S.
        Guedes)
       </para>
      </listitem>

      <listitem>
       <para>
        Show the possible values of <literal>enum</> types in <command>\dT+</>
        (David Fetter)
       </para>
      </listitem>

      <listitem>
       <para>
        Allow <command>\dC</> to accept a wildcard pattern, which matches
        either datatype involved in the cast (Tom)
       </para>
      </listitem>

      <listitem>
       <para>
        Make <command>\df</> not hide functions that take or return
        type <type>cstring</> (Tom)
       </para>

       <para>
        Previously, such functions were hidden because most of them are
        datatype I/O functions, which were deemed uninteresting.  The new
        policy about hiding system functions by default makes this wart
        unnecessary.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title><application>pg_dump</></title>
     <itemizedlist>

      <listitem>
       <para>
        Add a <literal>--no-tablespaces</> option to
        <application>pg_dump</>/<application>pg_dumpall</>/<application>pg_restore</>
        so that dumps can be restored to clusters that have non-matching
        tablespace layouts (Gavin Roy)
       </para>
      </listitem>

      <listitem>
       <para>
        Remove <option>-d</> and <option>-D</> options from
        <application>pg_dump</> and <application>pg_dumpall</> (Tom)
       </para>

       <para>
        These options were too frequently confused with the option to
        select a database name in other <productname>PostgreSQL</>
        client applications.  The functionality is still available,
        but you must now spell out the long option name
        <option>--inserts</> or <option>--column-inserts</>.
       </para>
      </listitem>

      <listitem>
       <para>
        Remove <option>-i</>/<option>--ignore-version</> option from
        <application>pg_dump</> and <application>pg_dumpall</> (Tom)
       </para>

       <para>
        Use of this option does not throw an error, but it has no
        effect.  This option was removed because the version checks
        are necessary for safety.
       </para>
      </listitem>

      <listitem>
       <para>
        Disable <varname>statement_timeout</> during dump and restore
        (Joshua Drake)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <application>pg_dump</>/<application>pg_dumpall</> option
        <option>--lock-wait-timeout</> (David Gould)
       </para>

       <para>
        This allows dumps to fail if unable to acquire a shared lock
        within the specified amount of time.
       </para>
      </listitem>

      <listitem>
       <para>
        Reorder <application>pg_dump</> <literal>--data-only</> output
        to dump tables referenced by foreign keys before
        the referencing tables (Tom)
       </para>

       <para>
        This allows data loads when foreign keys are already present.
        If circular references make a safe ordering impossible, a
        <literal>NOTICE</> is issued.
       </para>
      </listitem>

      <listitem>
       <para>
        Allow <application>pg_dump</>, <application>pg_dumpall</>, and
        <application>pg_restore</> to use a specified role (Benedek
        L<>szl<7A>)
       </para>
      </listitem>

      <listitem>
       <para>
        Allow <application>pg_restore</> to use multiple concurrent
        connections to do the restore (Andrew)
       </para>

       <para>
        The number of concurrent connections is controlled by the option
        <literal>--jobs</>.  This is supported only for custom-format archives.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

   </sect3>

   <sect3>
    <title>Programming Tools</title>

    <sect4>
     <title><application>libpq</></title>
     <itemizedlist>

      <listitem>
       <para>
        Allow the <type>OID</> to be specified when importing a large
        object, via new function <function>lo_import_with_oid()</> (Tatsuo)
       </para>
      </listitem>

      <listitem>
       <para>
        Add <quote>events</> support (Andrew Chernow, Merlin Moncure)
       </para>

       <para>
        This adds the ability to register callbacks to manage private
        data associated with <structname>PGconn</> and <structname>PGresult</>
        objects.
       </para>
      </listitem>

      <listitem>
       <para>
        Improve error handling to allow the return of multiple
        error messages as multi-line error reports (Magnus)
       </para>
      </listitem>

      <listitem>
       <para>
        Make <function>PQexecParams()</> and related functions return
        <varname>PGRES_EMPTY_QUERY</> for an empty query (Tom)
       </para>

       <para>
        They previously returned <varname>PGRES_COMMAND_OK</>.
       </para>
      </listitem>

      <listitem>
       <para>
        Document how to avoid the overhead of <function>WSACleanup()</>
        on Windows (Andrew Chernow)
       </para>
      </listitem>

      <listitem>
       <para>
        Make Kerberos use the same method to determine the username of the
        client as all other authentication methods (Magnus)
       </para>

       <para>
        Previously a special Kerberos-only API was used.
       </para>
      </listitem>
     </itemizedlist>

    </sect4>

    <sect4>
     <title><application>libpq</> <acronym>SSL</> (Secure Sockets Layer)
      support</title>
     <itemizedlist>

      <listitem>
       <para>
        Fix certificate validation for <acronym>SSL</> connections
        (Magnus)
       </para>

       <para>
        <application>libpq</> now supports verifying both the certificate
        and the name of the server when making <acronym>SSL</>
        connections. If a root certificate is not available to use for
        verification, <acronym>SSL</> connections will fail. The
        <literal>sslmode</> parameter is used to enable the certificate
        verification and set the level.
       </para>

       <para>
        The default is still not to do any verification, allowing connections
        to SSL enabled servers without requiring a root certificate on the
        client.
       </para>
      </listitem>

      <listitem>
       <para>
        Support wildcard server certificates (Magnus)
       </para>

       <para>
        If a certificate <acronym>CN</> starts with <literal>*</>, it will
        be treated as a wildcard when matching the hostname, allowing the
        use of the same certificate for multiple servers.
       </para>
      </listitem>

      <listitem>
       <para>
        Allow the file locations for client certificates to be specified
        (Mark Woodward, Alvaro, Magnus)
       </para>
      </listitem>

      <listitem>
       <para>
        Add a <function>PQinitOpenSSL</> function to allow greater control
        over OpenSSL/libcrypto initialization (Andrew Chernow)
       </para>
      </listitem>

      <listitem>
       <para>
        Make <application>libpq</> unregister its <application>OpenSSL</>
        callbacks when no database connections remain open
        (Bruce, Magnus, Russell Smith)
       </para>

       <para>
        This is required for applications that unload the libpq library,
        otherwise invalid <application>OpenSSL</> callbacks will remain.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title><application>ecpg</></title>
     <itemizedlist>

      <listitem>
       <para>
        Add localization support for messages (Euler Taveira de
        Oliveira)
       </para>
      </listitem>

      <listitem>
       <para>
        ecpg parser is now automatically generated from the server
        parser (Michael)
       </para>

       <para>
        Previously the ecpg parser was hand-maintained.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Server Programming Interface (<acronym>SPI</>)</title>
     <itemizedlist>

      <listitem>
       <para>
        Add support for single-use plans with out-of-line
        parameters (Tom)
       </para>
      </listitem>

      <listitem>
       <para>
        Add new <varname>SPI_OK_REWRITTEN</> return code for
        <function>SPI_execute()</> (Heikki)
       </para>

       <para>
        This is used when a command is rewritten to another type of
        command.
       </para>
      </listitem>

      <listitem>
       <para>
        Remove unnecessary inclusions from <filename>executor/spi.h</> (Tom)
       </para>

       <para>
        SPI-using modules might need to add some <literal>#include</>
        lines if they were depending on <filename>spi.h</> to include
        things for them.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

   </sect3>

   <sect3>
    <title>Build Options</title>
    <itemizedlist>

     <listitem>
      <para>
       Update build system to use <productname>Autoconf</> 2.61 (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Require <productname>GNU bison</> for source code builds (Peter)
      </para>

      <para>
       This has effectively been required for several years, but now there
       is no infrastructure claiming to support other parser tools.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <application>pg_config</> <literal>--htmldir</> option
       (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Pass <type>float4</> by value inside the server (Zoltan
       Boszormenyi)
      </para>

      <para>
       Add <application>configure</> option
       <literal>--disable-float4-byval</> to use the old behavior.
       External C functions that use old-style (version 0) call convention
       and pass or return <type>float4</> values will be broken by this
       change, so you may need the <application>configure</> option if you
       have such functions and don't want to update them.
      </para>
     </listitem>

     <listitem>
      <para>
       Pass <type>float8</>, <type>int8</>, and related datatypes
       by value inside the server on 64-bit platforms (Zoltan Boszormenyi)
      </para>

      <para>
       Add <application>configure</> option
       <literal>--disable-float8-byval</> to use the old behavior.
       As above, this change might break old-style external C functions.
      </para>
     </listitem>

     <listitem>
      <para>
       Add configure options <literal>--with-segsize</>,
       <literal>--with-blocksize</>, <literal>--with-wal-blocksize</>,
       <literal>--with-wal-segsize</> (Zdenek Kotala, Tom)
      </para>

      <para>
       This simplifies build-time control over several constants that
       previously could only be changed by editing
       <filename>pg_config_manual.h</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow threaded builds on <productname>Solaris</> 2.5 (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Use the system's <function>getopt_long()</> on <productname>Solaris</>
       (Zdenek Kotala, Tom)
      </para>

      <para>
       This makes option processing more consistent with what Solaris users
       expect.
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for the <productname>Sun Studio</> compiler on
       <productname>Linux</> (Julius Stroffek)
      </para>
     </listitem>

     <listitem>
      <para>
       Append the major version number to the backend <application>gettext</>
       domain, and the <literal>soname</> major version number to
       libraries' <application>gettext</> domain (Peter)
      </para>

      <para>
       This simplifies parallel installations of multiple versions.
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for code coverage testing with <application>gcov</>
       (Michelle Caisse)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow out-of-tree builds on <productname>Mingw</> and
       <productname>Cygwin</> (Richard Evans)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix the use of <productname>Mingw</> as a cross-compiling source
       platform (Peter)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Source Code</title>
    <itemizedlist>

     <listitem>
      <para>
       Support 64-bit time zone data files (Heikki)
      </para>

      <para>
       This adds support for daylight saving time (<acronym>DST</>)
       calculations beyond the year 2038.
      </para>
     </listitem>

     <listitem>
      <para>
       Deprecate use of platform's <type>time_t</> data type (Tom)
      </para>

      <para>
       Some platforms have migrated to 64-bit <type>time_t</>, some have
       not, and Windows can't make up its mind what it's doing.  Define
       <type>pg_time_t</> to have the same meaning as <type>time_t</>,
       but always be 64 bits (unless the platform has no 64-bit integer type),
       and use that type in all module APIs and on-disk data formats.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix bug in handling of the time zone database when cross-compiling
       (Richard Evans)
      </para>
     </listitem>

     <listitem>
      <para>
       Link backend object files in one step, rather than in stages
       (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve <application>gettext</> support to allow better translation
       of plurals (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Add message translation support to the PL languages (Alvaro, Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Add more <application>DTrace</> probes (Robert Lor)
      </para>
     </listitem>

     <listitem>
      <para>
       Enable <application>DTrace</> support on <application>Mac OS X
       Leopard</> and other non-Solaris platforms (Robert Lor)
      </para>
     </listitem>

     <listitem>
      <para>
       Simplify and standardize conversions between C strings and
       <type>text</> datums, by providing common functions for the purpose
       (Brendan Jurd, Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Clean up the <filename>include/catalog/</> header files so that
       frontend programs can include them without including
       <filename>postgres.h</>
       (Zdenek Kotala)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <type>name</> char-aligned, and suppress zero-padding of
       <type>name</> entries in indexes (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add a hook to let plug-ins monitor the executor (Itagaki
       Takahiro)
      </para>
     </listitem>

     <listitem>
      <para>
       Add a hook to allow the planner's statistics lookup behavior to
       be overridden (Simon Riggs)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>shmem_startup_hook()</> for custom shared memory
       requirements (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Replace the index access method <function>amgetmulti</> entry point
       with <function>amgetbitmap</>, and extend the API for
       <function>amgettuple</> to support run-time determination of
       operator lossiness (Heikki, Tom, Teodor)
      </para>

      <para>
       The API for GIN and GiST opclass <function>consistent</> functions
       has been extended as well.
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for partial-match searches in <acronym>GIN</> indexes
       (Teodor Sigaev, Oleg Bartunov)
      </para>
     </listitem>

     <listitem>
      <para>
       Replace <structname>pg_class</> column <structfield>reltriggers</>
       with boolean <structfield>relhastriggers</> (Simon)
      </para>

      <para>
       Also remove unused <structname>pg_class</> columns
       <structfield>relukeys</>, <structfield>relfkeys</>, and
       <structfield>relrefs</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Add a <structfield>relistemp</> column to <structname>pg_class</>
       to ease identification of temporary tables (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Move platform <acronym>FAQ</>s into the main documentation
       (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Prevent parser input files from being built with any conflicts
       (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for the <literal>KOI8U</> (Ukrainian) encoding
       (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Add Japanese message translations (Japan PostgreSQL Users Group)
      </para>

      <para>
       This used to be maintained as a separate project.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix problem when setting <varname>LC_MESSAGES</> on
       <application>MSVC</>-built systems (Hiroshi Inoue, Hiroshi
       Saito, Magnus)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Contrib</title>

    <itemizedlist>

     <listitem>
      <para>
       Add <filename>contrib/auto_explain</> to automatically run
       <command>EXPLAIN</> on queries exceeding a specified duration
       (Itagaki Takahiro, Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <filename>contrib/btree_gin</> to allow GIN indexes to
       handle more datatypes (Oleg, Teodor)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <filename>contrib/citext</> to provide a case-insensitive,
       multibyte-aware text data type (David Wheeler)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <filename>contrib/pg_stat_statements</> for server-wide
       tracking of statement execution statistics (Itagaki Takahiro)
      </para>
     </listitem>

     <listitem>
      <para>
       Add duration and query mode options to <filename>contrib/pgbench</>
       (Itagaki Takahiro)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix <filename>contrib/pgstattuple</> to handle tables and
       indexes with over 2 billion pages (Tatsuhito Kasahara)
      </para>
     </listitem>

     <listitem>
      <para>
       In <filename>contrib/fuzzystrmatch</>, add a version of the
       Levenshtein string-distance function that allows the user to
       specify the costs of insertion, deletion, and substitution
       (Volkan Yazici)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <filename>contrib/ltree</> support multibyte encodings
       (laser)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve <filename>contrib/dblink</>'s reporting of errors from
       the remote server (Joe Conway)
      </para>
     </listitem>

     <listitem>
      <para>
       Make sure <filename>contrib/dblink</> uses a password supplied
       by the user, and not accidentally taken from the server's
       <filename>.pgpass</> file (Joe Conway)
      </para>

      <para>
       This is a minor security enhancement.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>fsm_page_contents()</>
       to <filename>contrib/pageinspect</> (Heikki)
      </para>
     </listitem>

     <listitem>
      <para>
       Modify <function>get_raw_page()</> to support free space map
       (<filename>*_fsm</>) files.  Also update
       <filename>contrib/pg_freespacemap</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for multibyte encodings to <filename>contrib/pg_trgm</>
       (Teodor)
      </para>
     </listitem>

     <listitem>
      <para>
       Rewrite <filename>contrib/intagg</> to use new
       functions <function>array_agg()</> and <function>unnest()</>
       (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <filename>contrib/intarray</>'s definitions of the
       <literal>&lt;@</> and <literal>@&gt;</> operators (Tom)
      </para>

      <para>
       This avoids confusion with the equivalent built-in operators.
       If needed, the <filename>contrib/intarray</> implementations
       are still available under their historical names <literal>@</>
       and <literal>~</>.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>
  </sect2>
 </sect1>