| From: | Rolf Østvik <rolfostvik(at)yahoo(dot)no> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Worse perfomance on 8.2.0 than on 7.4.14 |
| Date: | 2007-01-01 15:19:05 |
| Message-ID: | 20070101151905.55545.qmail@web26309.mail.ukl.yahoo.com |
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| Thread: | |
| Lists: | pgsql-performance |
--- Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> skrev:
> Rolf =?iso-8859-1?q?=D8stvik?= <rolfostvik(at)yahoo(dot)no>
> writes:
> > I have a simple query which uses 32ms on 7.4.14
> and 1015ms on 8.2.0.
>
> There's something awfully strange about that 8.2
> plan --- if it knew
> that it'd have to scan all of uut_result_subset
> (which it should have
> known, if the stats were up-to-date),
I can't really see the need for it to do an sequence
scan, but that is me not knowing how things work.
>why did it use
> an indexscan
> rather than a seqscan? Are you sure you haven't
> tweaked any parameters
> you didn't tell us about, such as setting
> enable_seqscan = off?
I haven't touched enable_seqscan.
It could be that i have forgotton to tell you about a
parameter i have tweaked, but i doubt it.
Best regards
Rolf Østvik
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