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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: Andres Freund <andres@2ndquadrant.com>,
 Heikki Linnakangas <hlinnakangas@vmware.com>,
 Andrew Dunstan <andrew@dunslane.net>,
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Subject: Re: Something fishy happening on frogmouth
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Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
 message dated "Thu, 31 Oct 2013 08:06:48 -0400"
Date: Thu, 31 Oct 2013 10:29:17 -0400
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Robert Haas <robertmhaas@gmail.com> writes:
> On Thu, Oct 31, 2013 at 5:50 AM, Andres Freund <andres@2ndquadrant.com> wrote:
>> On 2013-10-31 11:33:28 +0200, Heikki Linnakangas wrote:
>>> Wait, that sounds horrible. If you kill -9 the server, and then rm -rf
>>> $PGDATA, the shared memory segment is leaked until next reboot?

>> Our main shared memory segment works the same way, doesn't it? And it
>> has for a long time.

> It does, and what's the alternative, anyway?

Well, what we expect from the existing shmem code is that restarting the
postmaster will clean things up, ie find and destroy the leaked shmem.
It sounds to me like this may not work like that, in which case I agree
with Heikki that it's not really acceptable.

Maybe, rather than trying to make the control segment's name random,
we should derive it from the data directory inode number, or some such?
That way we could find it reliably during restart.

			regards, tom lane


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