From: Richard Huxton <dev@archonet.com>
To: Wei Weng <wweng@kencast.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: concurrent connections is worse than serialization?
Date: Wed, 14 Aug 2002 15:49:57 +0100
Message-ID: <200208141549.57646.dev@archonet.com> (raw)
In-Reply-To: <1029334827.21470.2.camel@Monet>
References: <1029271170.16828.7.camel@Monet>
<200208141018.38875.dev@archonet.com>
<1029334827.21470.2.camel@Monet>
On Wednesday 14 Aug 2002 3:20 pm, Wei Weng wrote:
> On Wed, 2002-08-14 at 05:18, Richard Huxton wrote:
> > On Tuesday 13 Aug 2002 9:39 pm, Wei Weng wrote:
[30 connections is much slower than 1 connection 30 times]
> > What was the limiting factor during the test? Was the CPU maxed, memory,
> > disk I/O?
>
> No, none of the above was maxed. CPU usage that I paid attention to was
> at most a 48%.
Something must be the limiting factor. One of
- CPU
- Memory
- Disk I/O
- Database (configuration, or design)
- Application
If it's not CPU, is the system going into swap or are you seeing a lot of disk
activity?
> > I assume you've ruled the application end of things out.
>
> What does this mean?
I mean if you don't actually run the queries, then 30 separate processes is
fine?
If you can provide us with an EXPLAIN of the query and the relevant schema
definitions, we can rule out database design.
- Richard Huxton
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To: pgsql-sql@postgresql.org
Cc: dev@archonet.com, wweng@kencast.com
Subject: Re: concurrent connections is worse than serialization?
In-Reply-To: <200208141549.57646.dev@archonet.com>
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