Re: autovac hung/blocked

Ed L. wrote:

> Well, I think we clearly have an HPUX CPU bottleneck (long pri
> queue, high cpu utilization, high user cpu %, lots of processes
> "blocked on pri").
>
> It seems to get worst and slow all queries down across the board
> when autovac tries to vacuum a 15GB table. I'm guessing this is
> flushing the OS/DB caches, exacerbating the CPU bottleneck.
>
> I'm also not sure what to do about it beyond the customer buying
> some politically/financially expensive CPUs.

I suggest turning autovac off for that particular table, and doing the
vacuum during off-peak hours.

> The table in
> question appears to be the pathological case for vacuum: very
> large with lots of frequent UPDATEs. It's essentially a log
> table.

A big log table where the log entries are being updated? Certainly
sounds like a recipe for vacuum headaches.

--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support