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<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>CREATE EXTENSION</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="sql-createeventtrigger.html" title="CREATE EVENT TRIGGER" /><link rel="next" href="sql-createforeigndatawrapper.html" title="CREATE FOREIGN DATA WRAPPER" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">CREATE EXTENSION</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="sql-createeventtrigger.html" title="CREATE EVENT TRIGGER">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><th width="60%" align="center">SQL Commands</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.7 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="sql-createforeigndatawrapper.html" title="CREATE FOREIGN DATA WRAPPER">Next</a></td></tr></table><hr /></div><div class="refentry" id="SQL-CREATEEXTENSION"><div class="titlepage"></div><a id="id-1.9.3.64.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">CREATE EXTENSION</span></h2><p>CREATE EXTENSION — install an extension</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis">
CREATE EXTENSION [ IF NOT EXISTS ] <em class="replaceable"><code>extension_name</code></em>
[ WITH ] [ SCHEMA <em class="replaceable"><code>schema_name</code></em> ]
[ VERSION <em class="replaceable"><code>version</code></em> ]
[ CASCADE ]
</pre></div><div class="refsect1" id="id-1.9.3.64.5"><h2>Description</h2><p>
<code class="command">CREATE EXTENSION</code> loads a new extension into the current
database. There must not be an extension of the same name already loaded.
</p><p>
Loading an extension essentially amounts to running the extension's script
file. The script will typically create new <acronym class="acronym">SQL</acronym> objects such as
functions, data types, operators and index support methods.
<code class="command">CREATE EXTENSION</code> additionally records the identities
of all the created objects, so that they can be dropped again if
<code class="command">DROP EXTENSION</code> is issued.
</p><p>
The user who runs <code class="command">CREATE EXTENSION</code> becomes the
owner of the extension for purposes of later privilege checks, and
normally also becomes the owner of any objects created by the
extension's script.
</p><p>
Loading an extension ordinarily requires the same privileges that would
be required to create its component objects. For many extensions this
means superuser privileges are needed.
However, if the extension is marked <em class="firstterm">trusted</em> in
its control file, then it can be installed by any user who has
<code class="literal">CREATE</code> privilege on the current database.
In this case the extension object itself will be owned by the calling
user, but the contained objects will be owned by the bootstrap superuser
(unless the extension's script explicitly assigns them to the calling
user). This configuration gives the calling user the right to drop the
extension, but not to modify individual objects within it.
</p></div><div class="refsect1" id="id-1.9.3.64.6"><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">IF NOT EXISTS</code></span></dt><dd><p>
Do not throw an error if an extension with the same name already
exists. A notice is issued in this case. Note that there is no
guarantee that the existing extension is anything like the one that
would have been created from the currently-available script file.
</p></dd><dt><span class="term"><em class="replaceable"><code>extension_name</code></em></span></dt><dd><p>
The name of the extension to be
installed. <span class="productname">PostgreSQL</span> will create the
extension using details from the file
<code class="literal">SHAREDIR/extension/</code><em class="replaceable"><code>extension_name</code></em><code class="literal">.control</code>.
</p></dd><dt><span class="term"><em class="replaceable"><code>schema_name</code></em></span></dt><dd><p>
The name of the schema in which to install the extension's
objects, given that the extension allows its contents to be
relocated. The named schema must already exist.
If not specified, and the extension's control file does not specify a
schema either, the current default object creation schema is used.
</p><p>
If the extension specifies a <code class="literal">schema</code> parameter in its
control file, then that schema cannot be overridden with
a <code class="literal">SCHEMA</code> clause. Normally, an error will be raised if
a <code class="literal">SCHEMA</code> clause is given and it conflicts with the
extension's <code class="literal">schema</code> parameter. However, if
the <code class="literal">CASCADE</code> clause is also given,
then <em class="replaceable"><code>schema_name</code></em> is
ignored when it conflicts. The
given <em class="replaceable"><code>schema_name</code></em> will be
used for installation of any needed extensions that do not
specify <code class="literal">schema</code> in their control files.
</p><p>
Remember that the extension itself is not considered to be within any
schema: extensions have unqualified names that must be unique
database-wide. But objects belonging to the extension can be within
schemas.
</p></dd><dt><span class="term"><em class="replaceable"><code>version</code></em></span></dt><dd><p>
The version of the extension to install. This can be written as
either an identifier or a string literal. The default version is
whatever is specified in the extension's control file.
</p></dd><dt><span class="term"><code class="literal">CASCADE</code></span></dt><dd><p>
Automatically install any extensions that this extension depends on
that are not already installed. Their dependencies are likewise
automatically installed, recursively. The <code class="literal">SCHEMA</code> clause,
if given, applies to all extensions that get installed this way.
Other options of the statement are not applied to
automatically-installed extensions; in particular, their default
versions are always selected.
</p></dd></dl></div></div><div class="refsect1" id="id-1.9.3.64.7"><h2>Notes</h2><p>
Before you can use <code class="command">CREATE EXTENSION</code> to load an extension
into a database, the extension's supporting files must be installed.
Information about installing the extensions supplied with
<span class="productname">PostgreSQL</span> can be found in
<a class="link" href="contrib.html" title="Appendix F. Additional Supplied Modules">Additional Supplied Modules</a>.
</p><p>
The extensions currently available for loading can be identified from the
<a class="link" href="view-pg-available-extensions.html" title="54.2. pg_available_extensions"><code class="structname">pg_available_extensions</code></a>
or
<a class="link" href="view-pg-available-extension-versions.html" title="54.3. pg_available_extension_versions"><code class="structname">pg_available_extension_versions</code></a>
system views.
</p><div class="caution"><h3 class="title">Caution</h3><p>
Installing an extension as superuser requires trusting that the
extension's author wrote the extension installation script in a secure
fashion. It is not terribly difficult for a malicious user to create
trojan-horse objects that will compromise later execution of a
carelessly-written extension script, allowing that user to acquire
superuser privileges. However, trojan-horse objects are only hazardous
if they are in the <code class="varname">search_path</code> during script
execution, meaning that they are in the extension's installation target
schema or in the schema of some extension it depends on. Therefore, a
good rule of thumb when dealing with extensions whose scripts have not
been carefully vetted is to install them only into schemas for which
CREATE privilege has not been and will not be granted to any untrusted
users. Likewise for any extensions they depend on.
</p><p>
The extensions supplied with <span class="productname">PostgreSQL</span> are
believed to be secure against installation-time attacks of this sort,
except for a few that depend on other extensions. As stated in the
documentation for those extensions, they should be installed into secure
schemas, or installed into the same schemas as the extensions they
depend on, or both.
</p></div><p>
For information about writing new extensions, see
<a class="xref" href="extend-extensions.html" title="38.17. Packaging Related Objects into an Extension">Section 38.17</a>.
</p></div><div class="refsect1" id="id-1.9.3.64.8"><h2>Examples</h2><p>
Install the <a class="link" href="hstore.html" title="F.18. hstore">hstore</a> extension into the
current database, placing its objects in schema <code class="literal">addons</code>:
</p><pre class="programlisting">
CREATE EXTENSION hstore SCHEMA addons;
</pre><p>
Another way to accomplish the same thing:
</p><pre class="programlisting">
SET search_path = addons;
CREATE EXTENSION hstore;
</pre></div><div class="refsect1" id="id-1.9.3.64.9"><h2>Compatibility</h2><p>
<code class="command">CREATE EXTENSION</code> is a <span class="productname">PostgreSQL</span>
extension.
</p></div><div class="refsect1" id="id-1.9.3.64.10"><h2>See Also</h2><span class="simplelist"><a class="xref" href="sql-alterextension.html" title="ALTER EXTENSION"><span class="refentrytitle">ALTER EXTENSION</span></a>, <a class="xref" href="sql-dropextension.html" title="DROP EXTENSION"><span class="refentrytitle">DROP EXTENSION</span></a></span></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="sql-createeventtrigger.html" title="CREATE EVENT TRIGGER">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="sql-createforeigndatawrapper.html" title="CREATE FOREIGN DATA WRAPPER">Next</a></td></tr><tr><td width="40%" align="left" valign="top">CREATE EVENT TRIGGER </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 15.7 Documentation">Home</a></td><td width="40%" align="right" valign="top"> CREATE FOREIGN DATA WRAPPER</td></tr></table></div></body></html>
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