[Pgpool-general] pgpool-II load balance performance

[Yoshiyuki Asaba]

Hi,

From: Mikhail Kolesnik <mike at openbunker.org>
Subject: [Pgpool-general] pgpool-II load balance performance
Date: Wed, 30 Jan 2008 14:18:20 +0200

> >From my tests performance of pgpool in master/slave mode with 2 nodes is
> near 85% of a _single_ node performance on the 'tpc-b'-like queries,
> simple 'select' or complex 'select' with heavy sorting and few
> additional conditions. 

Could you try CVS HEAD? I've fixed a performance issue.

http://lists.pgfoundry.org/pipermail/pgpool-committers/2007-December/000578.html

You can get the version with the following operation.

  % cvs -d :pserver:anonymous at cvs.pgfoundry.org:/cvsroot/pgpool login
  <Enter>
  % cvs -d :pserver:anonymous at cvs.pgfoundry.org:/cvsroot/pgpool checkout pgpool-II


> Can also someone explain what 'connection_cache' in config file stands
> for, as I can't understand that from the documentation?

If connection_cache is true, pgpool keeps connections between pgpool
and PostgreSQL.

    pgpool <----> PostgreSQL

If false, pgpool connects to PostgreSQL servers every time.
You can see performance effect with pgbench -C option.

- with connection cache(connection_cache = true)

  % pgbench -C -c 1 -t 1000 -p 9999 -S bench
  starting vacuum...end.
  transaction type: SELECT only
  scaling factor: 10
  number of clients: 1
  number of transactions per client: 1000
  number of transactions actually processed: 1000/1000
  tps = 633.436583 (including connections establishing)
  tps = 633.437386 (excluding connections establishing)

- without connection cache(connection_cache = false)

  % pgbench -C -c 1 -t 1000 -p 9999 -S bench
  starting vacuum...end.
  transaction type: SELECT only
  scaling factor: 10
  number of clients: 1
  number of transactions per client: 1000
  number of transactions actually processed: 1000/1000
  tps = 25.806021 (including connections establishing)
  tps = 25.806021 (excluding connections establishing)

Regards,
--
Yoshiyuki Asaba
y-asaba at sraoss.co.jp