[pgpool-general: 589] Re: load balancing seems to be bottlenecked by performance of master

[Lonni J Friedman]

On Mon, Jun 4, 2012 at 3:40 PM, Tatsuo Ishii <ishii at postgresql.org> wrote:
>> You're correct, I only needed to perform a reload.  I kept this change
>> enabled for all of 36 seconds, and in that time there were 1597 times
>> that the following query was logged originating from the pgpool server
>> IP address:
>> SELECT count(*) FROM pg_catalog.pg_class AS c WHERE c.oid ...
>>
>> 3204 times that the following query was logged originating from the
>> pgpool server IP address:
>> SELECT count(*) FROM pg_class AS c, pg_namespace AS n WHERE c.relname ...
>>
>> Those numbers seem excessive to me, but perhaps this is
>> expected/normal?  It definitely seems like it would explain why perf
>> always degrades whenever the master is very busy, if that volume of
>> queries needs to be sustained.
>
> That depends on your use case. If client's query involves many tables,
> it requires many catalog lookups. Also the catalog cache of pgpool's
> life time is same as pgpool child process lifetime.  If you would show
> me the complete log, I could make more precise analysis.

Sure, attached as pg.log.gz.
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