Re: Possible Corrputed shared memory

On 1 August 2015 at 19:43, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> James Sebastian <james(dot)sebastian(at)gmail(dot)com> writes:
> > I attempted application stop and database shutdown using init scripts
> > followed by start.
> > The database failed to restart with the following error.
>
> > 2015-07-30 14:14:17 IST LOG: received immediate shutdown request
> > ...
>
> > The whole recovery took more than 2.5 hours to complete to come back to a
> > state to accept connections back. This caused considerable disruption in
> > normal service.
>
> If you use "immediate" mode shutdown, then yes, crash recovery is what
> will ensue. Think of that as being like the large red panic button that
> dumps the fuel rods out of a nuclear reactor: you push that button only
> when disaster is otherwise certain, because recovering will be slow and
> expensive.
>
> For an ordinary clean shutdown, you use "fast" mode, or "smart" mode
> if you're not expecting any long-lived client sessions.
>
> (If you're using a wrapper script that defaults to "immediate" mode,
> I'd advise changing that default.)
>

I am using default /etc/init.d/postgresql start|stop scripts.
I will check if it is using ordinary clean shutdown

>
> Also, if it took that long to recover, you might have raised the
> checkpoint interval settings too high.
>

I am using the following parameters

checkpoint_segments = 10 (from OS default 3)
checkpoint_completion_target = 0.8 (from OS default 0.5)
archive_mode=on
archive_timeout=600

Does any of the above looks too high ?

Regards,
James