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Re: Performance regression between 8.3 and 8.4 on heavy text indexing - Mailing list pgsql-performance

From Tom Lane
Subject Re: Performance regression between 8.3 and 8.4 on heavy text indexing
Date
Msg-id 17025.1251304185@sss.pgh.pa.us
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In response to Re: Performance regression between 8.3 and 8.4 on heavy text indexing  (gael@pilotsystems.net (Gaël Le Mignot))
Responses Re: Performance regression between 8.3 and 8.4 on heavy text indexing
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gael@pilotsystems.net (=?iso-8859-1?Q?Ga=EBl?= Le Mignot) writes:
> So it seems it was quite wrong about estimated matching rows (192 predicted, 10222 reals).

Yup.  What's even more interesting is that it seems the real win would
have been to use just the 'claude & duviau' condition (which apparently
matched only 14 rows).  8.3 had no hope whatever of understanding that,
it just got lucky.  8.4 should have figured it out, I'm thinking.
Does it help if you increase the statistics target for fulltext_tsv?
(Don't forget to re-ANALYZE after doing so.)

            regards, tom lane

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