# ALTER_FUNCTION - change the definition of a function - man(7) - [phpMan] _ALTER_ [_FUNCTION_(7)](https://www.chedong.com/phpMan.php/man/FUNCTION/7/markdown) PostgreSQL 16.14 Documentation _ALTER_ [_FUNCTION_(7)](https://www.chedong.com/phpMan.php/man/FUNCTION/7/markdown) ## 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)](https://www.chedong.com/phpMan.php/man/CREATEFUNCTION/7/markdown)) for more information. IMMUTABLE STABLE VOLATILE Change the volatility of the function to the specified setting. See CREATE FUNCTION ([**CREATE_FUNCTION**(7)](https://www.chedong.com/phpMan.php/man/CREATEFUNCTION/7/markdown)) 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)](https://www.chedong.com/phpMan.php/man/CREATEFUNCTION/7/markdown)) for more information about this capability. PARALLEL Change whether the function is deemed safe for parallelism. See CREATE FUNCTION ([**CREATE_FUNCTION**(7)](https://www.chedong.com/phpMan.php/man/CREATEFUNCTION/7/markdown)) for details. LEAKPROOF Change whether the function is considered leakproof or not. See CREATE FUNCTION ([**CREATE_FUNCTION**(7)](https://www.chedong.com/phpMan.php/man/CREATEFUNCTION/7/markdown)) for more information about this capability. COST _execution_cost_ Change the estimated execution cost of the function. See CREATE FUNCTION ([**CREATE_FUNCTION**(7)](https://www.chedong.com/phpMan.php/man/CREATEFUNCTION/7/markdown)) for more information. ROWS _result_rows_ Change the estimated number of rows returned by a set-returning function. See CREATE FUNCTION ([**CREATE_FUNCTION**(7)](https://www.chedong.com/phpMan.php/man/CREATEFUNCTION/7/markdown)) for more information. SUPPORT _support_function_ Set or change the planner support function to use for this function. See Section 38.11 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)](https://www.chedong.com/phpMan.php/man/SET/7/markdown) and Chapter 20 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)](https://www.chedong.com/phpMan.php/man/CREATEFUNCTION/7/markdown)), DROP FUNCTION ([**DROP_FUNCTION**(7)](https://www.chedong.com/phpMan.php/man/DROPFUNCTION/7/markdown)), ALTER PROCEDURE ([**ALTER_PROCEDURE**(7)](https://www.chedong.com/phpMan.php/man/ALTERPROCEDURE/7/markdown)), ALTER ROUTINE ([**ALTER_ROUTINE**(7)](https://www.chedong.com/phpMan.php/man/ALTERROUTINE/7/markdown)) PostgreSQL 16.14 2026 _ALTER_ [_FUNCTION_(7)](https://www.chedong.com/phpMan.php/man/FUNCTION/7/markdown)