Re: Slow SELECT on three or more clients

Operating system and some of the basic PostreSQL config settings would be helpful, plus any info you have on your disks, the size of the relevant tables, their structure and indexes & vacuum/analyze status ... plus what others have said:

Upgrade!

There are considerable improvements in, well, *everything* !, since 7.3 (we havew some database atb 7.4.x and I consider them out-of-date). Hopefully this list can provide help to get you through whatever your immediate crisis is, but do consider planning for this as soon as time and resource permit.

Data integrity is a _good_ thing!

Greg Williamson
DBA
GlobeXplorer LLC

-----Original Message-----
From: pgsql-performance-owner(at)postgresql(dot)org on behalf of Russell Smith
Sent: Wed 11/15/2006 5:31 AM
To: AMIR FRANCO D. JOVEN
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: [PERFORM] Slow SELECT on three or more clients

AMIR FRANCO D. JOVEN wrote:
> Hi!
>
> Im new to PostgreSQL.
>
> My current project uses PostgreSQL 7.3.4.
Upgrading your version of PostgreSQL to 8.1 will give you significant
benefits to performance.
>
> the problem is like this:
>
> I have a table with 94 fields and a select with only one resultset in
> only one client consumes about 0.86 seconds.
> The client executes three 'select' statements to perform the task
> which consumes 2.58 seconds.
> With only one client this is acceptable, but the real problem is as i
> add more clients, it goes more and more slower.
>
> for a single select with one field in one resultset, is 0.86 seconds
> normal?
You will need to attach the query.
EXPLAIN ANALYZE SELECT ...

where SELECT ... is your query. That will help us work out what the
problem is.

0.86 seconds might be slow for a query that returns 1 row, it might be
fast for a query that returns a large set with complex joins and where
conditions. Fast and slow are not objective terms. They are very
dependent on the query.

>
> I tried vacuuming and reindexing but to no avail.
> the total record count in that particular table is 456,541.
>
456,541 is not all that many records. But again you will need to post
more information for us to be able to assist.
> Thanks in advance.
>

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