Re: Migration study, step 2: rewriting queries

From: "Mikael Carneholm" <Mikael(dot)Carneholm(at)WirelessCar(dot)com>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "Pgsql performance" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Migration study, step 2: rewriting queries
Date: 2006-04-18 08:51:26
Message-ID: 7F10D26ECFA1FB458B89C5B4B0D72C2B3E3D30@sesrv12.wirelesscar.com
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>This should be fixed by the changes I made recently in
choose_bitmap_and
>--- it wasn't being aggressive about pruning overlapping AND conditions
when a sub-OR was involved. It's possible the new coding is >*too*
aggressive, and will reject indexes that it'd be profitable to include;
but at least it won't make this particular mistake.

Ok, cool. I don't have time to test this right now as the project has to
move on (and I guess testing the fix would require a dump+build CVS
version+restore), but as a temporary workaround I simly dropped the
xda_dat index (all queries on that table include the
person_information__id column anyway).

- Mikael

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