Re: Is the COMMUTATOR clause required for self commutative operators?

btober@seaworthysys.com wrote:
> In the command
>
> CREATE OPERATOR name (
>     PROCEDURE = func_name
>     [, LEFTARG = lefttype ] [, RIGHTARG = righttype ]
>     [, COMMUTATOR = com_op ] [, NEGATOR = neg_op ]
>     [, RESTRICT = res_proc ] [, JOIN = join_proc ]
>     [, HASHES ] [, MERGES ]
>     [, SORT1 = left_sort_op ] [, SORT2 = right_sort_op ]
>     [, LTCMP = less_than_op ] [, GTCMP = greater_than_op ]
> )
>
>
> Is omitting the COMMUTATOR option a problem at all in case of
> self-commutative operators?

It's an optimization clause, so if you omit it then you prevent certain
optimizations.  See
http://www.postgresql.org/docs/current/static/xoper-optimization.html#AEN29826
for details.