<!--
doc/src/sgml/ref/alter_function.sgml
PostgreSQL documentation
-->

<refentry id="sql-alterfunction">
 <indexterm zone="sql-alterfunction">
  <primary>ALTER FUNCTION</primary>
 </indexterm>

 <refmeta>
  <refentrytitle>ALTER FUNCTION</refentrytitle>
  <manvolnum>7</manvolnum>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>ALTER FUNCTION</refname>
  <refpurpose>change the definition of a function</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
<synopsis>
ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) ]
    <replaceable class="parameter">action</replaceable> [ ... ] [ RESTRICT ]
ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) ]
    RENAME TO <replaceable>new_name</replaceable>
ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) ]
    OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_ROLE | CURRENT_USER | SESSION_USER }
ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) ]
    SET SCHEMA <replaceable>new_schema</replaceable>
ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) ]
    [ NO ] DEPENDS ON EXTENSION <replaceable>extension_name</replaceable>

<phrase>where <replaceable class="parameter">action</replaceable> is one of:</phrase>

    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 <replaceable class="parameter">execution_cost</replaceable>
    ROWS <replaceable class="parameter">result_rows</replaceable>
    SUPPORT <replaceable class="parameter">support_function</replaceable>
    SET <replaceable class="parameter">configuration_parameter</replaceable> { TO | = } { <replaceable class="parameter">value</replaceable> | DEFAULT }
    SET <replaceable class="parameter">configuration_parameter</replaceable> FROM CURRENT
    RESET <replaceable class="parameter">configuration_parameter</replaceable>
    RESET ALL
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>ALTER FUNCTION</command> changes the definition of a
   function.
  </para>

  <para>
   You must own the function to use <command>ALTER FUNCTION</command>.
   To change a function's schema, you must also have <literal>CREATE</literal>
   privilege on the new schema.  To alter the owner, you must be able to
   <literal>SET ROLE</literal> to the new owning role, and that role must
   have <literal>CREATE</literal> 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.)
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

  <variablelist>
   <varlistentry>
    <term><replaceable class="parameter">name</replaceable></term>
    <listitem>
     <para>
      The name (optionally schema-qualified) of an existing function.  If no
      argument list is specified, the name must be unique in its schema.
     </para>