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ALTER OPERATOR FAMILY

ALTER OPERATOR FAMILY — change the definition of an operator family

Synopsis

ALTER OPERATOR FAMILYname USINGindex_method ADD  {  OPERATORstrategy_numberoperator_name (op_type,op_type )              [ FOR SEARCH | FOR ORDER BYsort_family_name ]   | FUNCTIONsupport_number [ (op_type [ ,op_type ] ) ]function_name [ (argument_type [, ...] ) ]  } [, ... ]ALTER OPERATOR FAMILYname USINGindex_method DROP  {  OPERATORstrategy_number (op_type [ ,op_type ] )   | FUNCTIONsupport_number (op_type [ ,op_type ] )  } [, ... ]ALTER OPERATOR FAMILYname USINGindex_method    RENAME TOnew_nameALTER OPERATOR FAMILYname USINGindex_method    OWNER TO {new_owner | CURRENT_ROLE | CURRENT_USER | SESSION_USER }ALTER OPERATOR FAMILYname USINGindex_method    SET SCHEMAnew_schema

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 withALTER 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; seeCREATE OPERATOR CLASS.)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 useALTER 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 toSection 36.16 for further information.

Parameters

TheOPERATOR andFUNCTION clauses can appear in any order.

Notes

Notice that theDROP 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, forDROP FUNCTION the type(s) to specify are the input data type(s) the function is intended to support; for GiST, SP-GiST and GIN 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. An SQL function is likely to be inlined into the calling query, which will prevent the optimizer from recognizing that the query matches an index.

BeforePostgreSQL 8.4, theOPERATOR clause could include aRECHECK option. This is no longer supported because whether an index operator is“lossy” is now determined on-the-fly at run time. 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 typesint4 andint2.

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 noALTER OPERATOR FAMILY statement in the SQL standard.

See Also