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

(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.

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.
Of course the docs can be postponed if you have a plan to write docs
when PERIOD types are introduced,
[1] http://developer.postgresql.org/pgdocs/postgres/btree-gist.html

The patch was not applied to 9.0, but the reason was just "no time to test" [2].
We have enough time to test for 9.1, so we can apply it now!
[2] http://archives.postgresql.org/pgsql-hackers/2010-05/msg01874.php

--
Itagaki Takahiro