[pgpool-general: 539] Re: load balancing seems to be bottlenecked by performance of master

Tatsuo Ishii ishii at postgresql.org
Tue May 29 09:55:25 JST 2012

> On Mon, May 28, 2012 at 5:23 PM, Tatsuo Ishii <ishii at postgresql.org> wrote:
>>> On Mon, May 28, 2012 at 3:54 PM, Tatsuo Ishii <ishii at sraoss.co.jp> wrote:
>>>>> What are the reasons for analysing system catalogs on primary server?
>>>> For example, if a table is a temporary one or not.
>>> Yes, but as I noted, I don't use temp tables at all.  If this is the
>>> primary justification, then its not doing me any good, and causing
>>> unnecessary negative performance impact.
>> But how does pgpool know that you are not going to use temporary
>> tables beforehand?
> Provide a new pgpool.conf option that tells it to ignore them (with
> the assumption that they do not exist).
>>> I understand if this isn't something you can fix right now, but I'm
>>> not even getting the impression that you consider this to be a design
>>> flaw.  A high write volume on the master should never impact the
>>> response time of any standby/slave with a read query.  This literally
>>> means that pgpool doesn't scale well in write heavy environments.
>> That's why I asked you any idea to solve the problem.
> I guess I don't understand why pgpool needs to look up the system
> catalogs on the write server.   Shouldn't they be identical on all
> servers?

You cannot assume that because streaming replication or slony are
async replication.

Also remember that temp tables can only be used on primary.
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp

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