NAME

       ALTER_FUNCTION - change the definition of a function

SYNOPSIS

       ALTER FUNCTION name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ]
           action [ ... ] [ RESTRICT ]
       ALTER FUNCTION name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ]
           RENAME TO new_name
       ALTER FUNCTION name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ]
           OWNER TO { new_owner | CURRENT_ROLE | CURRENT_USER | SESSION_USER }
       ALTER FUNCTION name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ]
           SET SCHEMA new_schema
       ALTER FUNCTION name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ]
           [ NO ] DEPENDS ON EXTENSION extension_name

       where action is one of:

           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 execution_cost
           ROWS result_rows
           SUPPORT support_function
           SET configuration_parameter { TO | = } { value | DEFAULT }
           SET configuration_parameter FROM CURRENT
           RESET configuration_parameter
           RESET ALL

DESCRIPTION

       ALTER FUNCTION changes the definition of a function.

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

PARAMETERS

       name
           The name (optionally schema-qualified) of an existing function. If no argument list is specified, the
           name must be unique in its schema.

       argmode
           The mode of an argument: IN, OUT, INOUT, or VARIADIC. If omitted, the default is IN. Note that ALTER
           FUNCTION does not actually pay any attention to OUT arguments, since only the input arguments are
           needed to determine the function's identity. So it is sufficient to list the IN, INOUT, and VARIADIC
           arguments.

       argname
           The name of an argument. Note that ALTER FUNCTION does not actually pay any attention to argument
           names, since only the argument data types are needed to determine the function's identity.

       argtype
           The data type(s) of the function's arguments (optionally schema-qualified), if any.

       new_name
           The new name of the function.

       new_owner
           The new owner of the function. Note that if the function is marked SECURITY DEFINER, it will
           subsequently execute as the new owner.

       new_schema
           The new schema for the function.

       DEPENDS ON EXTENSION extension_name
       NO DEPENDS ON EXTENSION extension_name
           This form marks the function as dependent on the extension, or no longer dependent on that extension
           if NO is specified. A function that's marked as dependent on an extension is dropped when the
           extension is dropped, even if CASCADE is not specified. A function can depend upon multiple
           extensions, and will be dropped when any one of those extensions is dropped.

       CALLED ON NULL INPUT
       RETURNS NULL ON NULL INPUT
       STRICT
           CALLED ON NULL INPUT changes the function so that it will be invoked when some or all of its
           arguments are null.  RETURNS NULL ON NULL INPUT or STRICT changes the function so that it is not
           invoked if any of its arguments are null; instead, a null result is assumed automatically. See CREATE
           FUNCTION (CREATE_FUNCTION(7)) for more information.

       IMMUTABLE
       STABLE
       VOLATILE
           Change the volatility of the function to the specified setting. See CREATE FUNCTION
           (CREATE_FUNCTION(7)) for details.

       [ EXTERNAL ] SECURITY INVOKER
       [ EXTERNAL ] SECURITY DEFINER
           Change whether the function is a security definer or not. The key word EXTERNAL is ignored for SQL
           conformance. See CREATE FUNCTION (CREATE_FUNCTION(7)) for more information about this capability.

       PARALLEL
           Change whether the function is deemed safe for parallelism. See CREATE FUNCTION (CREATE_FUNCTION(7))
           for details.

       LEAKPROOF
           Change whether the function is considered leakproof or not. See CREATE FUNCTION (CREATE_FUNCTION(7))
           for more information about this capability.

       COST execution_cost
           Change the estimated execution cost of the function. See CREATE FUNCTION (CREATE_FUNCTION(7)) for
           more information.

       ROWS result_rows
           Change the estimated number of rows returned by a set-returning function. See CREATE FUNCTION
           (CREATE_FUNCTION(7)) for more information.

       SUPPORT support_function
           Set or change the planner support function to use for this function. See Section 36.11 for details.
           You must be superuser to use this option.

           This option cannot be used to remove the support function altogether, since it must name a new
           support function. Use CREATE OR REPLACE FUNCTION if you need to do that.

       configuration_parameter
       value
           Add or change the assignment to be made to a configuration parameter when the function is called. If
           value is DEFAULT or, equivalently, RESET is used, the function-local setting is removed, so that the
           function executes with the value present in its environment. Use RESET ALL to clear all
           function-local settings.  SET FROM CURRENT saves the value of the parameter that is current when
           ALTER FUNCTION is executed as the value to be applied when the function is entered.

           See SET(7) and Chapter 19 for more information about allowed parameter names and values.

       RESTRICT
           Ignored for conformance with the SQL standard.

EXAMPLES

       To rename the function sqrt for type integer to square_root:

           ALTER FUNCTION sqrt(integer) RENAME TO square_root;

       To change the owner of the function sqrt for type integer to joe:

           ALTER FUNCTION sqrt(integer) OWNER TO joe;

       To change the schema of the function sqrt for type integer to maths:

           ALTER FUNCTION sqrt(integer) SET SCHEMA maths;

       To mark the function sqrt for type integer as being dependent on the extension mathlib:

           ALTER FUNCTION sqrt(integer) DEPENDS ON EXTENSION mathlib;

       To adjust the search path that is automatically set for a function:

           ALTER FUNCTION check_password(text) SET search_path = admin, pg_temp;

       To disable automatic setting of search_path for a function:

           ALTER FUNCTION check_password(text) RESET search_path;

       The function will now execute with whatever search path is used by its caller.

COMPATIBILITY

       This statement is partially compatible with the ALTER FUNCTION 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 RESTRICT key word,
       which is optional in PostgreSQL.

SEE ALSO

       CREATE FUNCTION (CREATE_FUNCTION(7)), DROP FUNCTION (DROP_FUNCTION(7)), ALTER PROCEDURE
       (ALTER_PROCEDURE(7)), ALTER ROUTINE (ALTER_ROUTINE(7))

PostgreSQL 17.5                                       2025                                     ALTER FUNCTION(7)