[pgpool-general: 588] Re: load balancing seems to be bottlenecked by performance of master

[Tatsuo Ishii]

> 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.
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
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