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