backend suddenly becomes slow, then remains slow

[Andrew Dunstan <andrew.dunstan@xxxxxxxxxxxxx>]

One of my clients has an odd problem. Every so often a backend will 
suddenly become very slow. The odd thing is that once this has happened 
it remains slowed down, for all subsequent queries. Zone reclaim is off. 
There is no IO or CPU spike, no checkpoint issues or stats timeouts, no 
other symptom that we can see. The problem was a lot worse that it is 
now, but two steps have alleviated it mostly, but not completely: much 
less aggressive autovacuuming and reducing the maximum lifetime of 
backends in the connection pooler to 30 minutes.

It's got us rather puzzled. Has anyone seen anything like this?

cheers

andrew


--
Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance