Re: PostgreSQL strugling during high load

Mindaugas Riauba wrote:

>>The "vacuum cost" parameters can be adjusted to make vacuums fired
>>by pg_autovacuum less of a burden. I haven't got any specific numbers
>>to suggest, but perhaps someone else does.
>
> It looks like that not only vacuum causes our problems. vacuum_cost
> seems to lower vacuum impact but we are still noticing slow queries "storm".
> We are logging queries that takes >2000ms to process.
> And there is quiet periods and then suddenly 30+ slow queries appears in
> log within the same second. What else could cause such behaviour?

I've seen that happen when you're placing (explicitly or
*implicitly*) locks on the records you're trying to update/delete.

If you're willing to investigate, `pg_locks' system view holds
information about db locks.

--
Cosimo