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<!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>ALTER FUNCTION</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-alterforeigntable.html" title="ALTER FOREIGN TABLE" /><link rel="next" href="sql-altergroup.html" title="ALTER GROUP" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">ALTER FUNCTION</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="sql-alterforeigntable.html" title="ALTER FOREIGN TABLE">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 11.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="sql-altergroup.html" title="ALTER GROUP">Next</a></td></tr></table><hr></hr></div><div class="refentry" id="SQL-ALTERFUNCTION"><div class="titlepage"></div><a id="id-1.9.3.14.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">ALTER FUNCTION</span></h2><p>ALTER FUNCTION — change the definition of a function</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis">
ALTER FUNCTION <em class="replaceable"><code>name</code></em> [ ( [ [ <em class="replaceable"><code>argmode</code></em> ] [ <em class="replaceable"><code>argname</code></em> ] <em class="replaceable"><code>argtype</code></em> [, ...] ] ) ]
<em class="replaceable"><code>action</code></em> [ ... ] [ RESTRICT ]
ALTER FUNCTION <em class="replaceable"><code>name</code></em> [ ( [ [ <em class="replaceable"><code>argmode</code></em> ] [ <em class="replaceable"><code>argname</code></em> ] <em class="replaceable"><code>argtype</code></em> [, ...] ] ) ]
RENAME TO <em class="replaceable"><code>new_name</code></em>
ALTER FUNCTION <em class="replaceable"><code>name</code></em> [ ( [ [ <em class="replaceable"><code>argmode</code></em> ] [ <em class="replaceable"><code>argname</code></em> ] <em class="replaceable"><code>argtype</code></em> [, ...] ] ) ]
OWNER TO { <em class="replaceable"><code>new_owner</code></em> | CURRENT_USER | SESSION_USER }
ALTER FUNCTION <em class="replaceable"><code>name</code></em> [ ( [ [ <em class="replaceable"><code>argmode</code></em> ] [ <em class="replaceable"><code>argname</code></em> ] <em class="replaceable"><code>argtype</code></em> [, ...] ] ) ]
SET SCHEMA <em class="replaceable"><code>new_schema</code></em>
ALTER FUNCTION <em class="replaceable"><code>name</code></em> [ ( [ [ <em class="replaceable"><code>argmode</code></em> ] [ <em class="replaceable"><code>argname</code></em> ] <em class="replaceable"><code>argtype</code></em> [, ...] ] ) ]
DEPENDS ON EXTENSION <em class="replaceable"><code>extension_name</code></em>
<span class="phrase">where <em class="replaceable"><code>action</code></em> is one of:</span>
CALLED ON NULL INPUT | RETURNS NULL ON NULL INPUT | STRICT
IMMUTABLE | STABLE | VOLATILE | [ NOT ] LEAKPROOF
[ EXTERNAL ] SECURITY INVOKER | [ EXTERNAL ] SECURITY DEFINER
PARALLEL { UNSAFE | RESTRICTED | SAFE }
COST <em class="replaceable"><code>execution_cost</code></em>
ROWS <em class="replaceable"><code>result_rows</code></em>
SET <em class="replaceable"><code>configuration_parameter</code></em> { TO | = } { <em class="replaceable"><code>value</code></em> | DEFAULT }
SET <em class="replaceable"><code>configuration_parameter</code></em> FROM CURRENT
RESET <em class="replaceable"><code>configuration_parameter</code></em>
RESET ALL
</pre></div><div class="refsect1" id="id-1.9.3.14.5"><h2>Description</h2><p>
<code class="command">ALTER FUNCTION</code> changes the definition of a
function.
</p><p>
You must own the function to use <code class="command">ALTER FUNCTION</code>.
To change a function's schema, you must also have <code class="literal">CREATE</code>
privilege on the new schema.
To alter the owner, you must also be a direct or indirect member of the new
owning role, and that role must have <code class="literal">CREATE</code> privilege on
the function's schema. (These restrictions enforce that altering the owner
doesn't do anything you couldn't do by dropping and recreating the function.
However, a superuser can alter ownership of any function anyway.)
</p></div><div class="refsect1" id="id-1.9.3.14.6"><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="replaceable"><code>name</code></em></span></dt><dd><p>
The name (optionally schema-qualified) of an existing function. If no
argument list is specified, the name must be unique in its schema.
</p></dd><dt><span class="term"><em class="replaceable"><code>argmode</code></em></span></dt><dd><p>
The mode of an argument: <code class="literal">IN</code>, <code class="literal">OUT</code>,
<code class="literal">INOUT</code>, or <code class="literal">VARIADIC</code>.
If omitted, the default is <code class="literal">IN</code>.
Note that <code class="command">ALTER FUNCTION</code> does not actually pay
any attention to <code class="literal">OUT</code> arguments, since only the input
arguments are needed to determine the function's identity.
So it is sufficient to list the <code class="literal">IN</code>, <code class="literal">INOUT</code>,
and <code class="literal">VARIADIC</code> arguments.
</p></dd><dt><span class="term"><em class="replaceable"><code>argname</code></em></span></dt><dd><p>
The name of an argument.
Note that <code class="command">ALTER FUNCTION</code> does not actually pay
any attention to argument names, since only the argument data
types are needed to determine the function's identity.
</p></dd><dt><span class="term"><em class="replaceable"><code>argtype</code></em></span></dt><dd><p>
The data type(s) of the function's arguments (optionally
schema-qualified), if any.
</p></dd><dt><span class="term"><em class="replaceable"><code>new_name</code></em></span></dt><dd><p>
The new name of the function.
</p></dd><dt><span class="term"><em class="replaceable"><code>new_owner</code></em></span></dt><dd><p>
The new owner of the function. Note that if the function is
marked <code class="literal">SECURITY DEFINER</code>, it will subsequently
execute as the new owner.
</p></dd><dt><span class="term"><em class="replaceable"><code>new_schema</code></em></span></dt><dd><p>
The new schema for the function.
</p></dd><dt><span class="term"><em class="replaceable"><code>extension_name</code></em></span></dt><dd><p>
The name of the extension that the function is to depend on.
</p></dd><dt><span class="term"><code class="literal">CALLED ON NULL INPUT</code><br /></span><span class="term"><code class="literal">RETURNS NULL ON NULL INPUT</code><br /></span><span class="term"><code class="literal">STRICT</code></span></dt><dd><p><code class="literal">CALLED ON NULL INPUT</code> changes the function so
that it will be invoked when some or all of its arguments are
null. <code class="literal">RETURNS NULL ON NULL INPUT</code> or
<code class="literal">STRICT</code> changes the function so that it is not
invoked if any of its arguments are null; instead, a null result
is assumed automatically. See <a class="xref" href="sql-createfunction.html" title="CREATE FUNCTION"><span class="refentrytitle">CREATE FUNCTION</span></a>
for more information.
</p></dd><dt><span class="term"><code class="literal">IMMUTABLE</code><br /></span><span class="term"><code class="literal">STABLE</code><br /></span><span class="term"><code class="literal">VOLATILE</code></span></dt><dd><p>
Change the volatility of the function to the specified setting.
See <a class="xref" href="sql-createfunction.html" title="CREATE FUNCTION"><span class="refentrytitle">CREATE FUNCTION</span></a> for details.
</p></dd><dt><span class="term"><code class="literal">[<span class="optional"> EXTERNAL </span>] SECURITY INVOKER</code><br /></span><span class="term"><code class="literal">[<span class="optional"> EXTERNAL </span>] SECURITY DEFINER</code></span></dt><dd><p>
Change whether the function is a security definer or not. The
key word <code class="literal">EXTERNAL</code> is ignored for SQL
conformance. See <a class="xref" href="sql-createfunction.html" title="CREATE FUNCTION"><span class="refentrytitle">CREATE FUNCTION</span></a> for more information about
this capability.
</p></dd><dt><span class="term"><code class="literal">PARALLEL</code></span></dt><dd><p>
Change whether the function is deemed safe for parallelism.
See <a class="xref" href="sql-createfunction.html" title="CREATE FUNCTION"><span class="refentrytitle">CREATE FUNCTION</span></a> for details.
</p></dd><dt><span class="term"><code class="literal">LEAKPROOF</code></span></dt><dd><p>
Change whether the function is considered leakproof or not.
See <a class="xref" href="sql-createfunction.html" title="CREATE FUNCTION"><span class="refentrytitle">CREATE FUNCTION</span></a> for more information about
this capability.
</p></dd><dt><span class="term"><code class="literal">COST</code> <em class="replaceable"><code>execution_cost</code></em></span></dt><dd><p>
Change the estimated execution cost of the function.
See <a class="xref" href="sql-createfunction.html" title="CREATE FUNCTION"><span class="refentrytitle">CREATE FUNCTION</span></a> for more information.
</p></dd><dt><span class="term"><code class="literal">ROWS</code> <em class="replaceable"><code>result_rows</code></em></span></dt><dd><p>
Change the estimated number of rows returned by a set-returning
function. See <a class="xref" href="sql-createfunction.html" title="CREATE FUNCTION"><span class="refentrytitle">CREATE FUNCTION</span></a> for more information.
</p></dd><dt><span class="term"><em class="replaceable"><code>configuration_parameter</code></em><br /></span><span class="term"><em class="replaceable"><code>value</code></em></span></dt><dd><p>
Add or change the assignment to be made to a configuration parameter
when the function is called. If
<em class="replaceable"><code>value</code></em> is <code class="literal">DEFAULT</code>
or, equivalently, <code class="literal">RESET</code> is used, the function-local
setting is removed, so that the function executes with the value
present in its environment. Use <code class="literal">RESET
ALL</code> to clear all function-local settings.
<code class="literal">SET FROM CURRENT</code> saves the value of the parameter that
is current when <code class="command">ALTER FUNCTION</code> is executed as the value
to be applied when the function is entered.
</p><p>
See <a class="xref" href="sql-set.html" title="SET"><span class="refentrytitle">SET</span></a> and
<a class="xref" href="runtime-config.html" title="Chapter 19. Server Configuration">Chapter 19</a>
for more information about allowed parameter names and values.
</p></dd><dt><span class="term"><code class="literal">RESTRICT</code></span></dt><dd><p>
Ignored for conformance with the SQL standard.
</p></dd></dl></div></div><div class="refsect1" id="id-1.9.3.14.7"><h2>Examples</h2><p>
To rename the function <code class="literal">sqrt</code> for type
<code class="type">integer</code> to <code class="literal">square_root</code>:
</p><pre class="programlisting">
ALTER FUNCTION sqrt(integer) RENAME TO square_root;
</pre><p>
</p><p>
To change the owner of the function <code class="literal">sqrt</code> for type
<code class="type">integer</code> to <code class="literal">joe</code>:
</p><pre class="programlisting">
ALTER FUNCTION sqrt(integer) OWNER TO joe;
</pre><p>
</p><p>
To change the schema of the function <code class="literal">sqrt</code> for type
<code class="type">integer</code> to <code class="literal">maths</code>:
</p><pre class="programlisting">
ALTER FUNCTION sqrt(integer) SET SCHEMA maths;
</pre><p>
</p><p>
To mark the function <code class="literal">sqrt</code> for type
<code class="type">integer</code> as being dependent on the extension
<code class="literal">mathlib</code>:
</p><pre class="programlisting">
ALTER FUNCTION sqrt(integer) DEPENDS ON EXTENSION mathlib;
</pre><p>
</p><p>
To adjust the search path that is automatically set for a function:
</p><pre class="programlisting">
ALTER FUNCTION check_password(text) SET search_path = admin, pg_temp;
</pre><p>
</p><p>
To disable automatic setting of <code class="varname">search_path</code> for a function:
</p><pre class="programlisting">
ALTER FUNCTION check_password(text) RESET search_path;
</pre><p>
The function will now execute with whatever search path is used by its
caller.
</p></div><div class="refsect1" id="id-1.9.3.14.8"><h2>Compatibility</h2><p>
This statement is partially compatible with the <code class="command">ALTER
FUNCTION</code> statement in the SQL standard. The standard allows more
properties of a function to be modified, but does not provide the
ability to rename a function, make a function a security definer,
attach configuration parameter values to a function,
or change the owner, schema, or volatility of a function. The standard also
requires the <code class="literal">RESTRICT</code> key word, which is optional in
<span class="productname">PostgreSQL</span>.
</p></div><div class="refsect1" id="id-1.9.3.14.9"><h2>See Also</h2><span class="simplelist"><a class="xref" href="sql-createfunction.html" title="CREATE FUNCTION"><span class="refentrytitle">CREATE FUNCTION</span></a>, <a class="xref" href="sql-dropfunction.html" title="DROP FUNCTION"><span class="refentrytitle">DROP FUNCTION</span></a>, <a class="xref" href="sql-alterprocedure.html" title="ALTER PROCEDURE"><span class="refentrytitle">ALTER PROCEDURE</span></a>, <a class="xref" href="sql-alterroutine.html" title="ALTER ROUTINE"><span class="refentrytitle">ALTER ROUTINE</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-alterforeigntable.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sql-commands.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="sql-altergroup.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">ALTER FOREIGN TABLE </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> ALTER GROUP</td></tr></table></div></body></html>
