Re: First steps with 8.3 and autovacuum launcher

Alvaro Herrera <alvherre@commandprompt.com> writes:
> So you say we should make any job that needs an exclusive lock on a
> table to be able to cancel a running autovac job?

I think we're going to be seeing complaints of this form until we do that.
The only reason this particular discussion is about pg_restore is that
that's the OP's first exposure to 8.3.

> If we did that, autovac couldn't do very much of anything.

In the worst case autovac could be starved out for a long time.
I don't have any immediate good idea about how to fix that, but
the worst consequences could be avoided if we disable the cancellation
ability when running an anti-wraparound vacuum.  Further down the road
(*not* 8.3), when we teach autovac about maintenance windows, it might
also disregard cancels during a maintenance window.
        regards, tom lane