NAME
ALTER OPERATOR FAMILY - change the definition of an operator family
SYNOPSIS
ALTER OPERATOR FAMILY name USING index_method ADD
{ OPERATOR strategy_number operator_name ( op_type, op_type )
| FUNCTION support_number [ ( op_type [ , op_type ] ) ] funcname ( argument_type [, ...] )
} [, ... ]
ALTER OPERATOR FAMILY name USING index_method DROP
{ OPERATOR strategy_number ( op_type [ , op_type ] )
| FUNCTION support_number ( op_type [ , op_type ] )
} [, ... ]
ALTER OPERATOR FAMILY name USING index_method RENAME TO newname
ALTER OPERATOR FAMILY name USING index_method OWNER TO newowner
DESCRIPTION
ALTER OPERATOR FAMILY changes the definition of an operator family. You
can add operators and support functions to the family, remove them from
the family, or change the family’s name or owner.
When operators and support functions are added to a family with ALTER
OPERATOR FAMILY, they are not part of any specific operator class
within the family, but are just ‘‘loose’’ within the family. This
indicates that these operators and functions are compatible with the
family’s semantics, but are not required for correct functioning of any
specific index. (Operators and functions that are so required should be
declared as part of an operator class, instead; see CREATE OPERATOR
CLASS [create_operator_class(7)].) PostgreSQL will allow loose members
of a family to be dropped from the family at any time, but members of
an operator class cannot be dropped without dropping the whole class
and any indexes that depend on it. Typically, single-data-type
operators and functions are part of operator classes because they are
needed to support an index on that specific data type, while cross-
data-type operators and functions are made loose members of the family.
You must be a superuser to use ALTER OPERATOR FAMILY. (This
restriction is made because an erroneous operator family definition
could confuse or even crash the server.)
ALTER OPERATOR FAMILY does not presently check whether the operator
family definition includes all the operators and functions required by
the index method, nor whether the operators and functions form a self-
consistent set. It is the user’s responsibility to define a valid
operator family.
Refer to in the documentation for further information.
PARAMETERS
name The name (optionally schema-qualified) of an existing operator
family.
index_method
The name of the index method this operator family is for.
strategy_number
The index method’s strategy number for an operator associated
with the operator family.
operator_name
The name (optionally schema-qualified) of an operator associated
with the operator family.
op_type
In an OPERATOR clause, the operand data type(s) of the operator,
or NONE to signify a left-unary or right-unary operator. Unlike
the comparable syntax in CREATE OPERATOR CLASS, the operand data
types must always be specified.
In an ADD FUNCTION clause, the operand data type(s) the function
is intended to support, if different from the input data type(s)
of the function. For B-tree and hash indexes it is not necessary
to specify op_type since the function’s input data type(s) are
always the correct ones to use. For GIN and GiST indexes it is
necessary to specify the input data type the function is to be
used with.
In a DROP FUNCTION clause, the operand data type(s) the function
is intended to support must be specified.
support_number
The index method’s support procedure number for a function
associated with the operator family.
funcname
The name (optionally schema-qualified) of a function that is an
index method support procedure for the operator family.
argument_types
The parameter data type(s) of the function.
newname
The new name of the operator family.
newowner
The new owner of the operator family.
The OPERATOR and FUNCTION clauses can appear in any order.
NOTES
Notice that the DROP syntax only specifies the ‘‘slot’’ in the operator
family, by strategy or support number and input data type(s). The name
of the operator or function occupying the slot is not mentioned. Also,
for DROP FUNCTION the type(s) to specify are the input data type(s) the
function is intended to support; for GIN and GiST indexes this might
have nothing to do with the actual input argument types of the
function.
Because the index machinery does not check access permissions on
functions before using them, including a function or operator in an
operator family is tantamount to granting public execute permission on
it. This is usually not an issue for the sorts of functions that are
useful in an operator family.
The operators should not be defined by SQL functions. A SQL function is
likely to be inlined into the calling query, which will prevent the
optimizer from recognizing that the query matches an index.
Before PostgreSQL 8.4, the OPERATOR clause could include a RECHECK
option. This is no longer supported because whether an index operator
is ‘‘lossy’’ is now determined on-the-fly at runtime. This allows
efficient handling of cases where an operator might or might not be
lossy.
EXAMPLES
The following example command adds cross-data-type operators and
support functions to an operator family that already contains B-tree
operator classes for data types int4 and int2.
ALTER OPERATOR FAMILY integer_ops USING btree ADD
-- int4 vs int2
OPERATOR 1 < (int4, int2) ,
OPERATOR 2 <= (int4, int2) ,
OPERATOR 3 = (int4, int2) ,
OPERATOR 4 >= (int4, int2) ,
OPERATOR 5 > (int4, int2) ,
FUNCTION 1 btint42cmp(int4, int2) ,
-- int2 vs int4
OPERATOR 1 < (int2, int4) ,
OPERATOR 2 <= (int2, int4) ,
OPERATOR 3 = (int2, int4) ,
OPERATOR 4 >= (int2, int4) ,
OPERATOR 5 > (int2, int4) ,
FUNCTION 1 btint24cmp(int2, int4) ;
To remove these entries again:
ALTER OPERATOR FAMILY integer_ops USING btree DROP
-- int4 vs int2
OPERATOR 1 (int4, int2) ,
OPERATOR 2 (int4, int2) ,
OPERATOR 3 (int4, int2) ,
OPERATOR 4 (int4, int2) ,
OPERATOR 5 (int4, int2) ,
FUNCTION 1 (int4, int2) ,
-- int2 vs int4
OPERATOR 1 (int2, int4) ,
OPERATOR 2 (int2, int4) ,
OPERATOR 3 (int2, int4) ,
OPERATOR 4 (int2, int4) ,
OPERATOR 5 (int2, int4) ,
FUNCTION 1 (int2, int4) ;
COMPATIBILITY
There is no ALTER OPERATOR FAMILY statement in the SQL standard.
SEE ALSO
CREATE OPERATOR FAMILY [create_operator_family(7)], DROP OPERATOR
FAMILY [drop_operator_family(7)], CREATE OPERATOR CLASS
[create_operator_class(7)], ALTER OPERATOR CLASS
[alter_operator_class(7)], DROP OPERATOR CLASS [drop_operator_class(7)]