Re: (9.1) btree_gist support for searching on "not equals"

On Sun, 2010-08-01 at 21:57 -0400, Robert Haas wrote:
> On Fri, Jul 16, 2010 at 1:19 AM, Jeff Davis <pgsql(at)j-davis(dot)com> wrote:
> > Thank you for the review.
> >
> > On Mon, 2010-07-12 at 17:17 +0900, Itagaki Takahiro wrote:
> >> (1) Exclusion constraints support for operators where "x <operator> x"
> >> is false (tiny patch)
> >> https://commitfest.postgresql.org/action/patch_view?id=307
> >> (2) btree_gist support for searching on <> ("not equals")
> >> https://commitfest.postgresql.org/action/patch_view?id=308
> >>
> >> Those patches should be committed at once because (2) requires (1) to work
> >> with EXCLUDE constraints. Also, (1) has no benefits without (2) because we
> >> have no use cases for <> as an index-able operator. Both patches are very
> >> simple and small, and worked as expected both "WHERE <>" and EXCLUDE
> >> constraints cases.
> >
> > It appears that Tom already committed (1).
> >
> >> I'd like to ask you to write additional documentation about btree_gist [1]
> >> that the module will be more useful when it is used with exclusion
> >> constraints together. Without documentation, no users find the usages.
> >
> > Good idea, new patch attached.
>
> It seems pretty odd to define a constant called
> BTNotEqualStrategyNumber in contrib/btree_gist. Shouldn't we either
> call this something else, or define it in access/skey.h? Considering
> that there seem to be some interesting gymnastics being done with
> BTMaxStrategyNumber, I'd vote for the former. Maybe just
> BtreeGistNotEqualStrategyNumber?

Sounds good to me.

At some point we may be interested to add this to BTree, as well. But we
can cross that bridge when we come to it.

Regards,
Jeff Davis