From: | Chris Mair <chrisnospam(at)1006(dot)org> |
---|---|
To: | Jonathan Sinclair <jonathan(dot)sinclair(at)molevalleyfarmers(dot)com> |
Cc: | pgsql-sql(at)postgresql(dot)org |
Subject: | Re: Query response time |
Date: | 2006-08-08 12:48:06 |
Message-ID: | 1155041286.3802.8.camel@dell.home.lan |
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Thread: | |
Lists: | pgsql-sql |
> 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(at)postgresql(dot)org as well, we might continue
discussion there.
Bye :)
Chris.
--
Chris Mair
http://www.1006.org
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