Re: src/ports/pgcheckdir.c - Ignore dot directories...

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Sean Chittenden <sean(at)chittenden(dot)org>
Cc: Kevin Grittner <kgrittn(at)ymail(dot)com>, Andrew Dunstan <andrew(at)dunslane(dot)net>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>, koobs(at)freebsd(dot)org
Subject: Re: src/ports/pgcheckdir.c - Ignore dot directories...
Date: 2013-02-05 15:36:42
Message-ID: 1463.1360078602@sss.pgh.pa.us
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Sean Chittenden <sean(at)chittenden(dot)org> writes:
> I agree it's not ideal for some filesystems, but being overly protective doesn't buy us much either, because in some setups, it's entirely acceptable.

No, it isn't. As several people have told you already, the idea of
letting a mount point be used directly as a data directory has been
suggested repeatedly, and rejected repeatedly, and this time is not
going to be any different. (Although I agree with Kevin that it's
about time we documented why not to do this.)

There are a couple of reasons why it's not good practice:

* mount-point directories really ought to be owned by root, or at least
by some user with more privilege than a DB server ought to have

* without a sub-directory, there's no simple cross-check to enforce that
the mount has actually happened. It's happened before that people have
had a server start up against a slow-to-mount NFS directory, and then
get completely confused when the mount did happen and the visible
database files got replaced. (The really nasty variants of this require
a startup script that will try to initdb automatically if it doesn't see
a database there.)

That's just what I can remember off the top of my head with insufficient
caffeine. If you check the archives for previous discussions you might
find some other good points.

regards, tom lane

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