Re: server auto-restarts and ipcs

From: "Ed L(dot)" <pgsql(at)bluepolka(dot)net>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: server auto-restarts and ipcs
Date: 2004-11-10 00:20:47
Message-ID: 200411091720.47996.pgsql@bluepolka.net
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On Tuesday November 9 2004 4:35, Tom Lane wrote:
> "Ed L." <pgsql(at)bluepolka(dot)net> writes:
> > I noticed that ipcs on my linux box has a command-line option to list
> > the pid that created the segment. Not sure if such a library exists in
> > usable form, but looking for segments owned by the downed postmaster's
> > pid would seem to be what is needed. Just a thought...
>
> [ thinks about it... ] Nah, it's still not bulletproof, because in a
> system reboot situation you can't trust the old PID either. It could
> easy be that the other guy gets both the PID and the shmem ID that
> belonged to you last time.

I see. Ipcs on my box also lists the date/time of shared memory segment
attach/detach/change (ipcs -t), but ...

> I've committed changes for 8.0 that mark a shmem segment with the inode
> of the associated data directory; that should be a stable enough ID to
> handle all routine-reboot cases. (If you had to restore your whole
> filesystem from backup tapes, it might be wrong, but you're going to be
> doing such recovery manually anyway ...)

...that will remove a major hassle for us and lots of other. Thanks.

Ed

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