Re: [GENERAL] pg_upgrade & tablespaces

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Adrian Klaver <adrian(dot)klaver(at)gmail(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, Joseph Kregloh <jkregloh(at)sproutloud(dot)com>, John R Pierce <pierce(at)hogranch(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: [GENERAL] pg_upgrade & tablespaces
Date: 2014-04-16 17:49:20
Message-ID: 20140416174920.GF7443@momjian.us
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On Sun, Jan 12, 2014 at 11:04:41PM -0500, Bruce Momjian wrote:
> > In the pgsql_old installation you have symlinks pointing back to the
> > current default location. As well pg_tablespace points back to
> > /usr/local/pgsql/data/ The issue is that there is not actually
> > anything there in the way of a tablespace. So when pg_upgrade runs
> > it tries to upgrade from /usr/local/pgsql/data/tblspc_dir to
> > /usr/local/pgsql/data/tblspc_dir where the first directory either
> > does not exist. or if the user went ahead and created the directory
> > in the new installation, is empty. What is really wanted is to
> > upgrade from /usr/local/pgsql_old/data/tblspc_dir to
> > /usr/local/pgsql/data/tblspc_dir. Right now the only way that
> > happens is with user intervention.
>
> Right, it points to _nothing_ in the _new_ cluster. Perhaps the
> simplest approach would be to check all the pg_tablespace locations to
> see if they point at real directories. If not, we would have to have
> the user update pg_tablespace and the symlinks. :-( Actually, even in
> 9.2+, those symlinks are going to point at the same "nothing". That
> would support checking the symlinks in all versions.

I have developed the attached patch which checks all tablespaces to make
sure the directories exist. I plan to backpatch this.

The reason we haven't seen this bug reported more frequently is that a
_database_ defined in a non-existent tablespace directory already throws
an backend error, so this check is only necessary where tables/indexes
(not databases) are defined in non-existant tablespace directories.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ Everyone has their own god. +

Attachment Content-Type Size
pg_upgrade.diff text/x-diff 1.6 KB

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