Date: Tue, 22 Aug 2006 19:36:08 -0600
From: Michael Fuhr <mike@fuhr.org>
To: "Craig A. James" <cjames@modgraph-usa.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Moving a tablespace
Message-ID: <20060823013608.GA60075@winnie.fuhr.org>
References: <44EBAC86.7070503@modgraph-usa.com>
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In-Reply-To: <44EBAC86.7070503@modgraph-usa.com>

On Tue, Aug 22, 2006 at 06:16:54PM -0700, Craig A. James wrote:
> Is there a way to move a tablespace to a new location without a 
> dump/restore?  I, er, this hypothetical guy, knows he can move it and put a 
> symbolic link in for /disk2, but this is somewhat unsatisfactory since 
> "/disk2" would have to exist forever.

The last paragraph of the Tablespaces documentation might be helpful:

http://www.postgresql.org/docs/8.1/interactive/manage-ag-tablespaces.html

"The directory $PGDATA/pg_tblspc contains symbolic links that point
to each of the non-built-in tablespaces defined in the cluster.
Although not recommended, it is possible to adjust the tablespace
layout by hand by redefining these links.  Two warnings: do not do
so while the postmaster is running; and after you restart the
postmaster, update the pg_tablespace catalog to show the new
locations.  (If you do not, pg_dump will continue to show the old
tablespace locations.)"

I just tested this and it appeared to work, but this hypothetical
DBA might want to wait for others to comment before proceeding.  He
might also want to initdb and populate a test cluster and practice
the procedure before doing it for real.

-- 
Michael Fuhr