To: Hannu Krosing <hannu@skype.net>
cc: Luke Lonergan <LLonergan@greenplum.com>, mark@mark.mielke.cc,
	Bruce Momjian <bruce@momjian.us>, Jie Zhang <jzhang@greenplum.com>,
	Gavin Sherry <swm@linuxworld.com.au>, pgsql-hackers@postgresql.org
Subject: Re: On-disk bitmap index patch 
In-reply-to: <1153852574.2924.15.camel@localhost.localdomain> 
References: <3E37B936B592014B978C4415F90D662D01F73ACF@MI8NYCMAIL06.Mi8.com>
	<17917.1153847188@sss.pgh.pa.us>
	<1153852574.2924.15.camel@localhost.localdomain>
Comments: In-reply-to Hannu Krosing <hannu@skype.net>
	message dated "Tue, 25 Jul 2006 21:36:13 +0300"
Date: Tue, 25 Jul 2006 16:31:53 -0400
Message-ID: <24222.1153859513@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Hannu Krosing <hannu@skype.net> writes:
> Ühel kenal päeval, T, 2006-07-25 kell 13:06, kirjutas Tom Lane:
>> The reason I have such high sales resistance is that we've carried the
>> hash and rtree AMs for years, hoping that someone would do the work to
>> make them actually worth using, with little result.

> What would be the use-case for hash indexes ? And what should be done to
> make them faster than btree ?

If we knew, we'd do it ;-)  But no one's put enough effort into it
to find out.

> and was'nt the rtree index recently deprecated in favour of GIST
> implementation of the same ?

Yeah, we finally gave up on rtree entirely.  I don't want to see any
other index AMs languishing in the closet like that.  If bitmap can
hold its own to the extent that people are interested in working on
it/improving it, then great, but I'm worried that it's not going to
have a wide enough use-case to attract maintainers.

			regards, tom lane