From: Tom Lane <tgl@sss.pgh.pa.us>
To: Ron Mayer <rm_pg@cheapcomplexdevices.com>
Cc: pgsql-hackers@postgreSQL.org
Subject: Re: On-disk bitmap index patch
Date: Tue, 25 Jul 2006 18:16:51 -0400
Message-ID: <24886.1153865811@sss.pgh.pa.us> (raw)
In-Reply-To: <44C692D9.3050406@cheapcomplexdevices.com>
References: <C0EAB84F.8FB4%jzhang@greenplum.com>
<200607250104.k6P14St25388@momjian.us>
<20060725015805.GA30087@mark.mielke.cc>
<5085.1153802202@sss.pgh.pa.us>
<44C692D9.3050406@cheapcomplexdevices.com>
Ron Mayer <rm_pg@cheapcomplexdevices.com> writes:
> Tom Lane wrote:
>> If you have to hit one tuple out of four, it's pretty much guaranteed
>> that you will need to fetch every heap page.
> I think it's not uncommon to have data that is more clustered than expected.
Sure, if the data is fairly static ... and now that there's a fillfactor
option for heaps, you can even tolerate (some low rate of) updates
without losing the clusteredness. However, that benefit accrues to
all index types not only bitmap.
regards, tom lane
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To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, rm_pg@cheapcomplexdevices.com
Subject: Re: On-disk bitmap index patch
In-Reply-To: <24886.1153865811@sss.pgh.pa.us>
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