Re: CIDR index use for '<<' operator

"Kendall Koning" <kkoning@egl.net> writes:
> Postgres doesn't seem to make use of indexes when doing operations with the
> CIDR '<<' (contains) operator.

You're right --- the system has no idea that the '<<' operator has any
relationship to the sort ordering of CIDR indexes.

Seems like it'd be possible to improve this along the same lines that
we use to make LIKE and regexp matches indexable: derive lower and
upper bounds on the CIDR variable from a 'cidr-var << cidr-constant'
clause, and use those to create 'cidr-var >= lower-bound AND
cidr-var <= upper-bound' indexscan limit clauses.

If you feel like tackling this, the "special index operator" support
in src/backend/optimizer/path/indxpath.c is the stuff that'd need to
be extended.

            regards, tom lane