| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Alvaro Herrera <alvherre(at)commandprompt(dot)com> |
| Cc: | Łukasz Jagiełło <lukasz(dot)jagiello(at)gforces(dot)pl>, Grzegorz Jaśkiewicz <gryzman(at)gmail(dot)com>, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Problems with autovacuum |
| Date: | 2009-05-26 23:59:19 |
| Message-ID: | 22047.1243382359@sss.pgh.pa.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> However I think there's a bigger problem here, which is that if the user
> has set naptime too low, i.e. to a value lower than
> number-of-databases * 100ms, we'll be running the (expensive)
> rebuild_database_list function on each iteration ... maybe we oughta put
> a lower bound on naptime based on the number of databases to avoid this
> problem.
Bingo, that's surely exactly what was happening to the OP. He had 2000
databases and naptime at (I assume) the default; so he was rerunning
rebuild_database_list every 100ms.
So that recovery code path needs some more thought. Maybe a lower bound
on how often to do rebuild_database_list? And/or don't set adl_next_worker
to less than 100ms in the future to begin with?
regards, tom lane
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Greg Smith | 2009-05-27 01:17:05 | Re: Hosted servers with good DB disk performance? |
| Previous Message | Dave Page | 2009-05-26 23:58:26 | Re: Hosted servers with good DB disk performance? |