From: Jona <jonanews@oismail.com>
To: Dennis Bjorklund <db@zigo.dhs.org>
Cc: Christopher Kings-Lynne <chriskl@familyhealth.com.au>
Cc: pgsql-performance@postgresql.org
Subject: Re: Query plan changes after pg_dump / pg_restore
Date: Thu, 09 Jun 2005 15:42:24 +0200
Message-ID: <42A84740.4010003@oismail.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0506091244490.24742-100000@zigo.dhs.org>
References: <Pine.LNX.4.44.0506091244490.24742-100000@zigo.dhs.org>
Thank you for the insight, any suggestion as to what table / columns I
should compare between the databases?
Cheers
Jona
Dennis Bjorklund wrote:
>On Thu, 9 Jun 2005, Jona wrote:
>
>
>
>>It's the same (physical) server as well as the same PostGreSQL daemon,
>>so yes.
>>
>>
>
>The only thing that can differ then is the statistics collected and the
>amount of dead space in tables and indexes (but since you both reindex and
>run vacuum full that should not be it).
>
>So comparing the statistics in the system tables is the only thing I can
>think of that might bring some light on the issue. Maybe someone else have
>some ideas.
>
>And as KL said, the effective_cache_size looked like it was way to small.
>With that setting bigger then pg should select index scans more often. It
>doesn't explain why the databases behave like they do now, but it might
>make pg select the same plan nevertheless.
>
>
>
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To: pgsql-performance@postgresql.org
Cc: jonanews@oismail.com, db@zigo.dhs.org, chriskl@familyhealth.com.au
Subject: Re: Query plan changes after pg_dump / pg_restore
In-Reply-To: <42A84740.4010003@oismail.com>
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