[pgpool-general: 739] pgpool causes high load

Benjamin Fras benjamin.fras at petafuel.de
Mon Jul 16 18:41:10 JST 2012

Dear list members,

since we have updated our pgpools to the latest stable version (3.1.3), we have regular peaks of high load on our machines. Every 5 to 10 minutes the server load (average 1 min load) raises up to 50, but then recovers within the next minutes to normal values again. CPU usage and IO wait are unaffected and show normal values during the whole time, so we cannot identify the processes that cause the load. Do you have any ideas what might cause this behavior? We didn't have that problems with the previous version of pgpool (3.0.4).

We suspected the root of the problem in child_life_time, which was set to 300. Thus we increased that value up to 7200 (2 hours), however it didn't improve the situation at all. Another measure was adjusting child_max_connections from 1500 to 1000 which also didn't solve the issue. Max_pool is set to 1.

Our pgpools are running in master/slave mode and postgres streaming replication (2 postgres 9.1 backends).
I want to add, that this problem is not that intense in another environment. However this environment does not have as many simultaneous connections (child_max_connections is set to 500),

Apart from that strange load problems everything works fine.


petaFuel GmbH
Benjamin Fras
IT Systemadministration

Münchner Strasse 4
85354 Freising

Tel.: +49 (0) 8161 4060 - 222
Fax: +49 (0) 8161 4060 - 401            eMail: Benjamin.Fras at petafuel.de<mailto:Vorname.Nachname at petafuel.de>

Geschäftsführer: Ludwig Adam, Dr. Peter Schönweitz
Amtsgericht München, HRB 133773


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