"Matthew T. O'Connor" <matthew@zeut.net> writes:
> Tom Lane wrote:
>> I was a bit worried about the scenario in which J Random Luser tries to
>> start the server twice and ends up with two autovacuum daemons attached
>> to the same postmaster. I'm not sure if this is possible, probable,
>> or dangerous ... but it seems like a point to consider.
> It is a good point to consider. Let me be a little more detailed in my
> explanation and see if that helps:
> * A never give up pg_autovacuum would only be used when run as a windows
> service.
> * The windows service control manager can still kill pg_autovacuum, so
> you shouldn't be able to start more than one that way.
> * You have always been able to run multiple pg_autovacuums, it's not
> advisable, and it's only bad side effect would be excessive, or more
> than expected, vacuum commands.
OK, that seems to take care of my worries above.
I agree with the point someone else made that if the service keeps trying
to start forever, it wouldn't be obvious to the user that it wasn't
working. So a limited time window seems best ... but I think it needs
to be at least five minutes.
regards, tom lane