Re: maintenance memory vs autovac

Guillaume Smet wrote:
> On Wed, Dec 3, 2008 at 2:00 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> It seems like mostly a confusion-generator to me.  Is there any actual
>> evidence that autovac should use a different maintenance_work_mem than
>> other processes?
> 
> IMHO, the point is that we were used to consider the
> maintenance_work_mem as a "one process at a time" thing. Even if it's
> not really true, we usually didn't do maintenance task on a concurrent
> basis.
> The autovacuum workers change that and make it a default behaviour (as
> we can have 3*maintenance_work_mem by default).

It's still one per process, it's just that autovac uses more than one
process. It's probably worthwhile to add a note about the effects of
autovacuum around the documentation of maintenance_work_mem, though.

//Magnus