Re: pg_autovacuum Win32 Service startup delay - Mailing list pgsql-patches

From Tom Lane
Subject Re: pg_autovacuum Win32 Service startup delay
Date
Msg-id 4113.1106670537@sss.pgh.pa.us
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In response to Re: pg_autovacuum Win32 Service startup delay  ("Matthew T. O'Connor" <matthew@zeut.net>)
List pgsql-patches
"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

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