[pgpool-general: 3289] High load, low CPU usage since 3.3.4

[Gersom van de Bunt]

Hi all,

Recently upgraded a production system from 3.2.4-2.1 to 3.3.4-1 (both backported Debian packages). With 3.2.4 the cpu usage was ~10% (8 cores), and load ~0.1. After upgrade, without any changes to configuration, cpu usage is the same, however, system load is now about 10.0 (5min. average). Only similar report i could find is from 2012:

http://www.sraoss.jp/pipermail/pgpool-general/2012-July/000827.html

This suggests the issue was resolved in 3.1-stable, so this is probably another issue we’re facing. Some more info;

- PGpool runs on dedicated hosts, in failover (watchdog) setup
- PGpool nodes have been upgrade from Debian squeeze to wheezy, while upgrading from 3.2.3 to 3.3.4
- No changes (configuration and/or updates) on backend (postgresql) nodes
- The load does not seem to affect functionality in any way (not in the application and neither in pcp commands or responsiveness)
- No changes in (use of) system resources are noticeable; no processes in IOwait, not more (or less) connections / changes in state of connections to/from pgpool)

I’ve attached our PGpool settings. Any ideas?

Thanks!

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