Re: Have vacuum emit a warning when it runs out of maintenance_work_mem

On 5/9/07, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Jim Nasby <decibel@decibel.org> writes:
> > Any time this happens it's generally a nasty surprise for users.
>
> Really?  Running out of work memory is expected on large tables.

Sure. Perhaps we should find a better error message but it's an
interesting information. Personnaly, I try to choose a sane value
depending on my database but I'm never sure it's really sufficient or
if I added 100MB it would have made a real difference.

> > It would be nice to throw them an explicit warning that it's occurring.
>
> I think this is a bad idea.  It's furthermore pretty useless in the
> autovacuum world, since no one is likely to see the warning.

IMHO we're far from having everyone using autovacuum. For instance,
for most of our customers, we prefer having a window for vacuuming
(from 3am for example) instead of having autovacuum fired in the
middle of the day during a load peak.
If we can shorten the window by having a sufficient value for
maintenance_work_mem, it's even nicer and Jim's patch could help us
with this point.

--
Guillaume