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Re: [HACKERS] choose_bitmap_and again (was Re: Strangely Variable Query Performance)
- From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
- To: "Dann Corbit" <DCorbit(at)connx(dot)com>
- Cc: "Alvaro Herrera" <alvherre(at)commandprompt(dot)com>, pgsql-hackers(at)postgresql(dot)org, "PostgreSQL Performance" <pgsql-performance(at)postgresql(dot)org>, "Steve" <cheetah(at)tanabi(dot)org>
- Subject: Re: [HACKERS] choose_bitmap_and again (was Re: Strangely Variable Query Performance)
- Date: Sat, 14 Apr 2007 11:52:45 -0400
"Dann Corbit" <DCorbit(at)connx(dot)com> writes: > Instead of sorting, I suggest the quickselect() algorithm, which is > O(n). What for? Common cases have less than half a dozen entries. That is not the place we need to be spending engineering effort --- what we need to worry about is what's the choice algorithm, not implementation details. regards, tom lane
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- Re: Strangely Variable Query Performance
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- Re: Strangely Variable Query Performance
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- Re: Strangely Variable Query Performance
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- Re: Strangely Variable Query Performance
- From: Tom Lane
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