Re: Vacuum takes forever

On May 29, 2007, at 12:03 PM, Joost Kraaijeveld wrote:
> vacuum_cost_delay = 200
> vacuum_cost_page_hit = 6
> #vacuum_cost_page_miss = 10             # 0-10000 credits
> #vacuum_cost_page_dirty = 20            # 0-10000 credits
> vacuum_cost_limit = 100

I didn't see anyone else mention this, so...

Those settings are *very* aggressive. I'm not sure why you upped the
cost of page_hit or dropped the cost_limit, but I can tell you the
effect: vacuum will sleep at least every 17 pages... even if those
pages were already in shared_buffers and vacuum didn't have to dirty
them. I really can't think of any reason you'd want to do that.

I do find vacuum_cost_delay to be an extremely useful tool, but
typically I'll set it to between 10 and 20 and leave the other
parameters alone.
--
Jim Nasby                                            jim@nasby.net
EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)