Alvaro Herrera wrote:
> Michael Paesold wrote:
>> Simon Riggs wrote:
>>> On Thu, 2007-10-25 at 13:41 -0300, Alvaro Herrera wrote:
>> ...
>>>> FWIW I disagree with cancelling just any autovac work automatically; in
>>>> my patch I'm only cancelling if it's analyze, on the grounds that if
>>>> you have really bad luck you can potentially lose a lot of work that
>>>> vacuum did. We can relax this restriction when we have cancellable
>>>> vacuum.
>>> That was requested by others, not myself, but I did agree with the
>>> conclusions. The other bad luck might be that you don't complete some
>>> critical piece of work in the available time window because an automated
>>> job kicked in.
>> Yeah, I thought we had agreed that we must cancel all auto vacuum/analyzes,
>> on the ground that foreground operations are usually more important than
>> maintenance tasks.
>
> What this means is that autovacuum will be starved a lot of the time,
> and in the end you will only vacuum the tables when you run out of time
> for Xid wraparound.
Well, only if you do a lot of schema changes. 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?
Best Regards
Michael Paesold