<para>
Add or change the assignment to be made to a configuration parameter
when the function is called. If
<replaceable>value</replaceable> is <literal>DEFAULT</literal>
or, equivalently, <literal>RESET</literal> is used, the function-local
setting is removed, so that the function executes with the value
present in its environment. Use <literal>RESET
ALL</literal> to clear all function-local settings.
<literal>SET FROM CURRENT</literal> saves the value of the parameter that
is current when <command>ALTER FUNCTION</command> is executed as the value
to be applied when the function is entered.
</para>
<para>
See <xref linkend="sql-set"/> and
<xref linkend="runtime-config"/>
for more information about allowed parameter names and values.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>RESTRICT</literal></term>
<listitem>
<para>
Ignored for conformance with the SQL standard.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Examples</title>
<para>
To rename the function <literal>sqrt</literal> for type
<type>integer</type> to <literal>square_root</literal>:
<programlisting>
ALTER FUNCTION sqrt(integer) RENAME TO square_root;
</programlisting>
</para>
<para>
To change the owner of the function <literal>sqrt</literal> for type
<type>integer</type> to <literal>joe</literal>:
<programlisting>
ALTER FUNCTION sqrt(integer) OWNER TO joe;
</programlisting>
</para>
<para>
To change the schema of the function <literal>sqrt</literal> for type
<type>integer</type> to <literal>maths</literal>:
<programlisting>
ALTER FUNCTION sqrt(integer) SET SCHEMA maths;
</programlisting>
</para>
<para>
To mark the function <literal>sqrt</literal> for type
<type>integer</type> as being dependent on the extension
<literal>mathlib</literal>:
<programlisting>
ALTER FUNCTION sqrt(integer) DEPENDS ON EXTENSION mathlib;
</programlisting>
</para>
<para>
To adjust the search path that is automatically set for a function:
<programlisting>
ALTER FUNCTION check_password(text) SET search_path = admin, pg_temp;
</programlisting>
</para>
<para>
To disable automatic setting of <varname>search_path</varname> for a function:
<programlisting>
ALTER FUNCTION check_password(text) RESET search_path;
</programlisting>
The function will now execute with whatever search path is used by its
caller.
</para>
</refsect1>
<refsect1>
<title>Compatibility</title>
<para>
This statement is partially compatible with the <command>ALTER
FUNCTION</command> 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 <literal>RESTRICT</literal> key word, which is optional in
<productname>PostgreSQL</productname>.
</para>
</refsect1>
<refsect1>
<title>See Also</title>
<simplelist type="inline">
<member><xref linkend="sql-createfunction"/></member>
<member><xref linkend="sql-dropfunction"/></member>
<member><xref linkend="sql-alterprocedure"/></member>
<member><xref linkend="sql-alterroutine"/></member>
</simplelist>
</refsect1>
</refentry>