From: | mark(at)mark(dot)mielke(dot)cc |
---|---|
To: | Luke Lonergan <llonergan(at)greenplum(dot)com> |
Cc: | Bruce Momjian <bruce(at)momjian(dot)us>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Dann Corbit <DCorbit(at)connx(dot)com>, "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com>, Jie Zhang <jzhang(at)greenplum(dot)com>, Mark Kirkwood <markir(at)paradise(dot)net(dot)nz>, Josh Berkus <josh(at)agliodbs(dot)com>, Gavin Sherry <swm(at)linuxworld(dot)com(dot)au>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: On-disk bitmap index patch |
Date: | 2006-07-29 04:26:23 |
Message-ID: | 20060729042622.GA22145@mark.mielke.cc |
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Lists: | pgsql-hackers |
On Fri, Jul 28, 2006 at 02:43:23PM -0700, Luke Lonergan wrote:
> On 7/28/06 1:25 PM, "Bruce Momjian" <bruce(at)momjian(dot)us> wrote:
> > What we don't want to happen is for us to release bitmapped indexes, and
> > find out later that btree is better in all cases. Then we have to tell
> > people not to use bitmapped indexes until we fix it in the next major
> > releasse. FYI, that is basically where we are right now with hash
> > indexes.
> On this thread people have presented results that show clear and irrefutable
> evidence that there are use cases where bitmap indexes outperform Btree for
> many datatypes on realistic problems, including the TPC-H benchmark.
Irrefutable is a little optimistic, don't you think? :-)
There is reason to believe that a bitmap index is useful in some
scenarios. We're not yet clear on what these are, whether they apply
to production use scenarios, or whether b-tree could not be optimized
to be better.
I support you - I want to see these great things for myself.
But irrefutable? Irrefutable is not true. :-)
Cheers,
mark
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