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ALTER FUNCTION
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ALTER FUNCTION

ALTER FUNCTION — change the definition of a function

Synopsis

ALTER FUNCTIONname [ ( [ [argmode ] [argname ]argtype [, ...] ] ) ]action [ ... ] [ RESTRICT ]ALTER FUNCTIONname [ ( [ [argmode ] [argname ]argtype [, ...] ] ) ]    RENAME TOnew_nameALTER FUNCTIONname [ ( [ [argmode ] [argname ]argtype [, ...] ] ) ]    OWNER TO {new_owner | CURRENT_ROLE | CURRENT_USER | SESSION_USER }ALTER FUNCTIONname [ ( [ [argmode ] [argname ]argtype [, ...] ] ) ]    SET SCHEMAnew_schemaALTER FUNCTIONname [ ( [ [argmode ] [argname ]argtype [, ...] ] ) ]    [ NO ] DEPENDS ON EXTENSIONextension_namewhereaction 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 }    COSTexecution_cost    ROWSresult_rows    SUPPORTsupport_function    SETconfiguration_parameter { TO | = } {value | DEFAULT }    SETconfiguration_parameter FROM CURRENT    RESETconfiguration_parameter    RESET ALL

Description

ALTER FUNCTION changes the definition of a function.

You must own the function to useALTER FUNCTION. To change a function's schema, you must also haveCREATE privilege on the new schema. To alter the owner, you must be able toSET ROLE to the new owning role, and that role must haveCREATE 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, orVARIADIC. If omitted, the default isIN. Note thatALTER FUNCTION does not actually pay any attention toOUT arguments, since only the input arguments are needed to determine the function's identity. So it is sufficient to list theIN,INOUT, andVARIADIC arguments.

argname

The name of an argument. Note thatALTER 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 markedSECURITY DEFINER, it will subsequently execute as the new owner.

new_schema

The new schema for the function.

DEPENDS ON EXTENSIONextension_name NO DEPENDS ON EXTENSIONextension_name

This form marks the function as dependent on the extension, or no longer dependent on that extension ifNO is specified. A function that's marked as dependent on an extension is dropped when the extension is dropped, even ifCASCADE 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 orSTRICT changes the function so that it is not invoked if any of its arguments are null; instead, a null result is assumed automatically. SeeCREATE FUNCTION for more information.

IMMUTABLE STABLE VOLATILE

Change the volatility of the function to the specified setting. SeeCREATE FUNCTION for details.

[ EXTERNAL] SECURITY INVOKER [ EXTERNAL] SECURITY DEFINER

Change whether the function is a security definer or not. The key wordEXTERNAL is ignored for SQL conformance. SeeCREATE FUNCTION for more information about this capability.

PARALLEL

Change whether the function is deemed safe for parallelism. SeeCREATE FUNCTION for details.

LEAKPROOF

Change whether the function is considered leakproof or not. SeeCREATE FUNCTION for more information about this capability.

COSTexecution_cost

Change the estimated execution cost of the function. SeeCREATE FUNCTION for more information.

ROWSresult_rows

Change the estimated number of rows returned by a set-returning function. SeeCREATE FUNCTION for more information.

SUPPORTsupport_function

Set or change the planner support function to use for this function. SeeSection 37.11 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. UseCREATE 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. Ifvalue isDEFAULT or, equivalently,RESET is used, the function-local setting is removed, so that the function executes with the value present in its environment. UseRESET ALL to clear all function-local settings.SET FROM CURRENT saves the value of the parameter that is current whenALTER FUNCTION is executed as the value to be applied when the function is entered.

SeeSET andChapter 18 for more information about allowed parameter names and values.

RESTRICT

Ignored for conformance with the SQL standard.

Examples

To rename the functionsqrt for typeinteger tosquare_root:

ALTER FUNCTION sqrt(integer) RENAME TO square_root;

To change the owner of the functionsqrt for typeinteger tojoe:

ALTER FUNCTION sqrt(integer) OWNER TO joe;

To change the schema of the functionsqrt for typeinteger tomaths:

ALTER FUNCTION sqrt(integer) SET SCHEMA maths;

To mark the functionsqrt for typeinteger as being dependent on the extensionmathlib:

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 ofsearch_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 theALTER 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 theRESTRICT key word, which is optional inPostgres Pro.