<!-- doc/src/sgml/contrib.sgml -->

<appendix id="contrib">
 <title>Additional Supplied Modules and Extensions</title>

 <para>
  This appendix and the next one contain information on the
  optional components
  found in the <literal>contrib</literal> directory of the
  <productname>PostgreSQL</productname> distribution.
  These include porting tools, analysis utilities,
  and plug-in features that are not part of the core PostgreSQL system.
  They are separate mainly
  because they address a limited audience or are too experimental
  to be part of the main source tree.  This does not preclude their
  usefulness.
 </para>

 <para>
  This appendix covers extensions and other server plug-in module
  libraries found in
  <literal>contrib</literal>.  <xref linkend="contrib-prog"/> covers utility
  programs.
 </para>

 <para>
  When building from the source distribution, these optional
  components are not built
  automatically, unless you build the "world" target
  (see <xref linkend="build"/>).
  You can build and install all of them by running:
<screen>
<userinput>make</userinput>
<userinput>make install</userinput>
</screen>
  in the <literal>contrib</literal> directory of a configured source tree;
  or to build and install
  just one selected module, do the same in that module's subdirectory.
  Many of the modules have regression tests, which can be executed by
  running:
<screen>
<userinput>make check</userinput>
</screen>
  before installation or
<screen>
<userinput>make installcheck</userinput>
</screen>
  once you have a <productname>PostgreSQL</productname> server running.
 </para>

 <para>
  If you are using a pre-packaged version of <productname>PostgreSQL</productname>,
  these components are typically made available as a separate subpackage,
  such as <literal>postgresql-contrib</literal>.
 </para>

 <para>
  Many components supply new user-defined functions, operators, or types,
  packaged as <firstterm>extensions</firstterm>.
  To make use of one of these extensions, after you have installed the code
  you need to register the new SQL objects in the database system.
  This is done by executing
  a <xref linkend="sql-createextension"/> command.  In a fresh database,
  you can simply do

<programlisting>
CREATE EXTENSION <replaceable>extension_name</replaceable>;
</programlisting>

  This command registers the new SQL objects in the current database only,
  so you need to run it in every database in which you want
  the extension's facilities to be available.  Alternatively, run it in
  database <literal>template1</literal> so that the extension will be copied into
  subsequently-created databases by default.
 </para>

 <para>
  For all extensions, the <command>CREATE EXTENSION</command> command must be
  run by a database superuser, unless the extension is
  considered <quote>trusted</quote>.  Trusted extensions can be run by any
  user who has <literal>CREATE</literal> privilege on the current
  database.  Extensions that are trusted are identified as such in the
  sections that follow.  Generally, trusted extensions are ones that cannot
  provide access to outside-the-database functionality.
 </para>

 <para id="contrib-trusted-extensions">
  The following extensions are trusted in a default installation:

  <simplelist type="vert" columns="4">
   <member><xref linkend="btree-gin"/></member>
   <member><xref linkend="btree-gist"/></member>
   <member><xref linkend="citext"/></member>
   <member><xref linkend="cube"/></member>
   <member><xref linkend="dict-int"/></member>
   <member><xref linkend="fuzzystrmatch"/></member>
   <member><xref linkend="hstore"/></member>
   <member><xref linkend="intarray"/></member>
   <member><xref linkend="isn"/></member>
   <member><xref linkend="lo"/></member>
   <member><xref linkend="ltree"/></member>
   <member><xref linkend="pgcrypto"/></member>
   <member><xref linkend="pgtrgm"/></member>
   <member><xref linkend="seg"/></member>
   <member><xref linkend="tablefunc"/></member>
   <member><xref linkend="tcn"/></member>
   <member><xref linkend="tsm-system-rows"/></member>
   <member><xref linkend="tsm-system-time"/></member>
   <member><xref linkend="unaccent"/></member>
   <member><xref linkend="uuid-ossp"/></member>
  </simplelist>
 </para>

 <para>
  Many extensions allow you to install their objects in a schema of your
  choice.  To do that, add <literal>SCHEMA
  <replaceable>schema_name</replaceable></literal> to the <command>CREATE EXTENSION</command>
  command.  By default, the objects will be placed in your current creation
  target schema, which in turn defaults to <literal>public</literal>.
 </para>

 <para>
  Note, however, that some of these components are not <quote>extensions</quote>
  in this sense, but are loaded into the server in some other way, for instance
  by way of
  <xref linkend="guc-shared-preload-libraries"/>.  See the documentation of each
  component for details.
 </para>

 &amcheck;
 &auth-delay;
 &auto-explain;
 &basebackup-to-shell;
 &basic-archive;
 &bloom;
 &btree-gin;
 &btree-gist;
 &citext;
 &cube;
 &dblink;
 &dict-int;
 &dict-xsyn;
 &earthdistance;
 &file-fdw;
 &fuzzystrmatch;
 &hstore;
 &intagg;
 &intarray;
 &isn;
 &lo;
 &ltree;
 &pageinspect;
 &passwordcheck;
 &pgbuffercache;
 &pgcrypto;
 &pgfreespacemap;
 &pgprewarm;
 &pgrowlocks;
 &pgstatstatements;
 &pgstattuple;
 &pgsurgery;
 &pgtrgm;
 &pgvisibility;
 &pgwalinspect;
 &postgres-fdw;
 &seg;
 &sepgsql;
 &contrib-spi;
 &sslinfo;
 &tablefunc;
 &tcn;
 &test-decoding;
 &tsm-system-rows;
 &tsm-system-time;
 &unaccent;
 &uuid-ossp;
 &xml2;

</appendix>

<!--
These are two separate appendixes because it is difficult to mix regular
sections (for extensions) and refentries (for programs) in one chapter or
appendix.  And we do want the programs as refentries so that we can produce man
pages.
-->

<appendix id="contrib-prog">
 <title>Additional Supplied Programs</title>

 <para>
  This appendix and the previous one contain information regarding the modules that
  can be found in the <literal>contrib</literal> directory of the
  <productname>PostgreSQL</productname> distribution.  See <xref linkend="contrib"/> for
  more information about the <literal>contrib</literal> section in general and
  server extensions and plug-ins found in <literal>contrib</literal>
  specifically.
 </para>

 <para>
  This appendix covers utility programs found in <literal>contrib</literal>.
  Once installed, either from source or a packaging system, they are found in
  the <filename>bin</filename> directory of the
  <productname>PostgreSQL</productname> installation and can be used like any
  other program.
 </para>

 <sect1 id="contrib-prog-client">
  <title>Client Applications</title>

  <para>
   This section covers <productname>PostgreSQL</productname> client
   applications in <literal>contrib</literal>.  They can be run from anywhere,
   independent of where the database server resides.  See
   also <xref linkend="reference-client"/> for information about client
   applications that are part of the core <productname>PostgreSQL</productname>
   distribution.
  </para>

 &oid2name;
 &vacuumlo;
 </sect1>

 <sect1 id="contrib-prog-server">
  <title>Server Applications</title>

  <para>
   Some applications run on the <productname>PostgreSQL</productname> server
   itself.  Currently, no such applications are included in the
   <literal>contrib</literal> directory.  See also <xref
   linkend="reference-server"/> for information about server applications that
   are part of the core <productname>PostgreSQL</productname> distribution.
  </para>

 </sect1>
</appendix>
