Changes the definition of a function.
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>
ALTER FUNCTION <name> ( [ [<argmode>] [<argname>] <argtype> [, ...] ] )
SET SCHEMA <new_schema>
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}
EXECUTE ON { ANY | MASTER | ALL SEGMENTS | INITPLAN }
COST <execution_cost>
SET <configuration_parameter> { TO | = } { <value> | DEFAULT }
SET <configuration_parameter> FROM CURRENT
RESET <configuration_parameter>
RESET ALL
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.)
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.
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.
SECURITY DEFINER
, it will subsequently run as the new owner.
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.
EXTERNAL
is ignored for SQL conformance. See
CREATE FUNCTION
for more information about this capability.
The EXECUTE ON
attributes specify where (master or segment instance) a function runs when it is invoked during the query execution process.
EXECUTE ON ANY
(the default) indicates that the function can be run on the master, or any segment instance, and it returns the same result regardless of where it is run. Greenplum Database determines where the function runs.
EXECUTE ON MASTER
indicates that the function must run only on the master instance.
EXECUTE ON ALL SEGMENTS
indicates that the function must run on all primary segment instances, but not the master, for each invocation. The overall result of the function is the UNION ALL
of the results from all segment instances.
EXECUTE ON INITPLAN
indicates that the function contains an SQL command that dispatches queries to the segment instances and requires special processing on the master instance by Greenplum Database when possible.
EXECUTE ON
attributes, see
CREATE FUNCTION.
DEFAULT
or, equivalently,
RESET
is used, the function-local setting is removed, and the function runs 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 run as the value to be applied when the function is entered.
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
:
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 math
:
ALTER FUNCTION sqrt(integer) SET SCHEMA math;
To adjust the search path that is automatically set for a function:
ALTER FUNCTION check_password(text) RESET search_path;
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.
CREATE FUNCTION, DROP FUNCTION
Parent topic: SQL Commands