Re: Autovacuum cancellation

Tom Lane wrote:
> Gregory Stark <stark@enterprisedb.com> writes:
> > I assume the right thing happens if multiple deadlock check signals fire for
> > the same autovacuum?
>
> Multiple signals shouldn't be a problem, but late-arriving ones could be.
> It might be worth having autovac explicitly clear QueryCancelPending
> after it's finished a table, so that a SIGINT sent because of activity
> on one table couldn't force cancellation of vacuum on the next one.

Ok, committed; I snuck that in as well, but I'm not sure how to test
that it works.

I adjusted the comments -- I think they're more correct now.  I also
added a puny paragraph to lmgr/README.

--
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support