On Thu, Oct 25, 2007 at 03:54:28PM -0400, Andrew Dunstan wrote:
> Simon Riggs wrote:
> >On Thu, 2007-10-25 at 13:51 -0400, Andrew Dunstan wrote:
> >>Michael Paesold wrote:
> >>
> >>>In the previous discussion, Simon and me agreed that schema
> >>>changes should not happen on a regular basis on production
> >>>systems.
> >>>
> >>>Shouldn't we rather support the regular usage pattern instead of
> >>>the uncommon one? Users doing a lot of schema changes are the
> >>>ones who should have to work around issues, not those using a
> >>>DBMS sanely. No?
> >>>
> >>Unfortunately, doing lots of schema changes is a very common
> >>phenomenon. It makes me uncomfortable too, but saying that those
> >>who do it have to work around issues isn't acceptable IMNSHO -
> >>it's far too widely done.
> >
> >We didn't agree that DDL was uncommon, we agreed that running DDL
> >was more important than running an auto VACUUM. DDL runs very
> >quickly, unless blocked, though holds up everybody else. So you
> >must run it at pre-planned windows. VACUUMs can run at any time, so
> >a autoVACUUM shouldn't be allowed to prevent DDL from running. The
> >queuing DDL makes other requests queue behind it, even ones that
> >would normally have been able to execute at same time as the
> >VACUUM.
> >
> >Anyway, we covered all this before. I started off saying we
> >shouldn't do this and Heikki and Michael came up with convincing
> >arguments, for me, so now I think we should allow autovacuums to be
> >cancelled.
>
> Perhaps I misunderstood, or have been mistunderstood :-) - I am
> actually agreeing that autovac should not block DDL.
+1 here for having autovacuum not block DDL :)
Cheers,
David (for what it's worth)
--
David Fetter <david@fetter.org> http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
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