Message-ID: <4926E2B2.9050202@archonet.com>
Date: Fri, 21 Nov 2008 16:32:50 +0000
From: Richard Huxton <dev@archonet.com>
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To: Andrus <kobruleht2@hot.ee>
CC: PFC <lists@peufeu.com>, pgsql-performance@postgresql.org
Subject: Re: Hash join on int takes 8..114 seconds
References: <gg1sv3$27fr$1@news.hub.org> <49253FE1.3070706@archonet.com>
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Andrus wrote:
>> - what's the size of the dataset relative to the RAM ?
> 
> Db size is 7417 MB
> relevant table sizes in desc by size order:
> 
>      1        40595 dok                                 2345 MB


>      2         1214 pg_shdepend                         2259 MB
>      6         1232 pg_shdepend_depender_index          795 MB
>      7         1233 pg_shdepend_reference_index         438 MB

These three are highly suspicious. They track dependencies between
system object (so you can't drop function F because trigger T depends on
it).

http://www.postgresql.org/docs/8.3/static/catalog-pg-shdepend.html

You've got 3.5GB of data there, which is a *lot* of dependencies.

Try "SELECT count(*) FROM pg_shdepend".

If it's not a million rows, then the table is bloated. Try (as postgres
or some other db superuser) "vacuum full pg_shdepend" and a "reindex
pg_shdepend".

If it is a million rows, you'll need to find out why. Do you have a lot
of temporary tables that aren't being dropped or something similar?

-- 
  Richard Huxton
  Archonet Ltd