From: Chris Mair <chrisnospam@1006.org>
To: Jonathan Sinclair <jonathan.sinclair@molevalleyfarmers.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: Query response time
Date: Tue, 08 Aug 2006 14:48:06 +0200
Message-ID: <1155041286.3802.8.camel@dell.home.lan> (raw)
In-Reply-To: <746457F7E51F3B4BB53A8447D7204B78E456@MVGMAIL.mvg.local>
References: <746457F7E51F3B4BB53A8447D7204B78E456@MVGMAIL.mvg.local>
> I am using PostgresSQL 7.4 and having some serious performance issues.
> Trawling through the archives and previous posts the only visible advice
> I could see was either by running vacuum or setting the fsynch flag to
> false.
>
> I am using tables that only contain approx 2GB of data. However
> performing a number of simple conditional select statements takes a
> great deal of time. Putting limits on the data obviously reduces the
> time, but there is still a delay. (Note: on one particular query I set
> the limit to 538 and the query returns in under 2mins if the limit
> becomes 539 the query loops indefinitely!)
> >From previous experience I know these delays are longer than both
> Informix and MySql. In some instances it takes so long I end up having
> to kill the query.
Please run the command "analyze" on your database (you can do that with
the psql shell), then post to this list:
- your query
- the output of the command "explain + your query"
- the layout of the tables concerned by the query (
"\d tablename" from psql)
> The install was performed by yum onto a RAID server using Centos. I am
> sure there is something fundamentally wrong for I can't believe that
> postgres would have the reputation it has based on the statistics I'm
> getting. Does anyone have any advice?
> The data I am using was imported from an Informix system as part of a
> migration strategy.
> I know this is long shot but I hope someone can shed some light.
If you're on pgsql-performance@postgresql.org as well, we might continue
discussion there.
Bye :)
Chris.
--
Chris Mair
http://www.1006.org
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To: pgsql-sql@postgresql.org
Cc: chrisnospam@1006.org, jonathan.sinclair@molevalleyfarmers.com
Subject: Re: Query response time
In-Reply-To: <1155041286.3802.8.camel@dell.home.lan>
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