ALTER FUNCTION

where action is one of:

{IMMUTABLE | STABLE | VOLATILE}
{[EXTERNAL] SECURITY INVOKER | [EXTERNAL] SECURITY DEFINER}
COST <execution_cost>
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 also be a direct or indirect member of the new owning role, and that role must have CREATE privilege on the function’s schema. (These restrictions enforce that altering the owner does not do anything you could not do by dropping and recreating the function. However, a superuser can alter ownership of any function anyway.)

name

The name (optionally schema-qualified) of an existing function.

argmode

The mode of an argument: either IN, OUT, INOUT, or VARIADIC. If omitted, the default is IN. Note that 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.

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.

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 for more information.

IMMUTABLE

STABLE

VOLATILE

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

[ EXTERNAL ] SECURITY INVOKER

[ EXTERNAL ] SECURITY DEFINER

COST execution_cost

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

configuration_parameter

value

Set or change the value of a configuration parameter when the function is called. If value is DEFAULT or, equivalently, RESET is used, the function-local setting is removed, and the function executes with the value present in its environment. Use to clear all function-local settings. SET FROM CURRENT applies the session’s current value of the parameter when the function is entered.

RESTRICT

Ignored for conformance with the SQL standard.

Notes

Greenplum Database has limitations on the use of functions defined as STABLE or VOLATILE. See CREATE FUNCTION for more information.

To rename the function sqrt for type integer 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 math:

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

ALTER FUNCTION check_password(text) RESET search_path;

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, or change the owner, schema, or volatility of a function. The standard also requires the RESTRICT key word, which is optional in Greenplum Database.

Parent topic: SQL Command Reference