Re: Autovacuum launcher doesn't notice death of postmaster immediately

On Tue, Jun 12, 2007 at 12:23:50PM +0200, Zdenek Kotala wrote:
> Alvaro Herrera wrote:
> >Zeugswetter Andreas ADI SD escribió:
> >>>>>>>The launcher is set up to wake up in autovacuum_naptime
> >>seconds
> >>>>>>>at most.
> >>>>Imho the fix is usually to have a sleep loop.
> >>>This is what we have. The sleep time depends on the schedule
> >>>of next vacuum for the closest database in time. If naptime
> >>>is high, the sleep time will be high (depending on number of
> >>>databases needing attention).
> >>No, I meant a "while (sleep 1(or 10) and counter < longtime) check for
> >>exit" instead of "sleep longtime".
> >
> >Ah; yes, what I was proposing (or thought about proposing, not sure if I
> >posted it or not) was putting a upper limit of 10 seconds in the sleep
> >(bgwriter sleeps 10 seconds if configured to not do anything). Though
> >10 seconds may seem like an eternity for systems like the ones Peter was
> >talking about, where there is a script trying to restart the server as
> >soon as the postmaster dies.
>
> There is also one "wild" solution. Postmaster and bgwriter will connect
> with socket/pipe and select command will be used instead sleep. If
> connection unexpectedly fails, select finish immediately and we are able
> to handle this issue asap. This socket should be used also in some
> special case when we need wake up it faster.

Given the amount of problems we've had with pipes on win32, let's try to
avoid adding extra ones unless they're really necessary. If split-sleep
works, that seems a safer bet.

//Magnus