| From: | Janning Vygen <vygen(at)gmx(dot)de> |
|---|---|
| To: | "Chris Hutchinson" <chris(at)hutchinsonsoftware(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: EXPLAIN ANALYZE much slower than running query normally |
| Date: | 2004-10-11 12:15:56 |
| Message-ID: | 200410111415.56547.vygen@gmx.de |
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| Lists: | pgsql-performance |
Am Dienstag, 5. Oktober 2004 08:49 schrieb Chris Hutchinson:
> Running a trivial query in v7.4.2 (installed with fedora core2) using
> EXPLAIN ANALYZE is taking considerably longer than just running the query
> (2mins vs 6 secs). I was using this query to quickly compare a couple of
> systems after installing a faster disk.
>
> Is this sort of slowdown to be expected?
no.
did you run VACCUM ANALYZE before? you should do it after pg_restore your db
to a new filesystem
in which order did you ran the queries. If you start your server and run two
equal queries, the second one will be much faster because of some or even all
data needed to answer the query is still in the shared buffers.
janning
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