Why threads every 30 seconds?

Bryan Henderson <bryanh@giraffe-data.com> writes:

Looking at audit logs, I see that my Postgresql server generates a new thread
precisely every 30 seconds, in two series (so 4 threads every minute). This
is an otherwise idle server.

Does anyone know what these threads are for? Just curious.

Autovacuum, likely. The rate would depend on your autovacuum_naptime
and how many active databases you have.

regards, tom lane

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Looking at audit logs, I see that my Postgresql server generates a new thread
precisely every 30 seconds, in two series (so 4 threads every minute). This
is an otherwise idle server.

Does anyone know what these threads are for? Just curious.

Autovacuum, likely. The rate would depend on your autovacuum_naptime
and how many active databases you have.

Yep, that was it, thanks.

I had the default autovacuum_naptime of 1 minute, and had two Postgresql
clusters runing. I turned off autovacuum and these threads disappeared.

Still not sure how it comes to twice a minute per cluster. There are 5
databases, and as far as I know, a client connection to one of them, not
doing anything, while this was happening.

--
Bryan Henderson San Jose, California

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