Re: Big 7.1 open items

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Bruce Momjian <pgman@candle.pha.pa.us>
Cc: Hiroshi Inoue <Inoue@tpf.co.jp>, Peter Eisentraut <peter_e@gmx.net>, Jan Wieck <JanWieck@Yahoo.com>, PostgreSQL-development <pgsql-hackers@postgreSQL.org>, "Ross J. Reedstrom" <reedstrm@rice.edu>
Date: 2000-06-21T16:24:44Z
Lists: pgsql-hackers
Bruce Momjian <pgman@candle.pha.pa.us> writes:
>> Well, that opens up a completely different issue, which is what about
>> moving tables from one tablespace to another?

> Are you suggesting that doing dbname/locname is somehow harder to do
> that?  If you are, I don't understand why.

It doesn't make it harder, but it still seems pointless to have the
extra directory level.  Bear in mind that if we go with all-OID
filenames then you're not going to be looking at "loc1" and "loc2"
anyway, but at "5938171" and "8583727".  It's not much of a convenience
to the admin to see that, so we might as well save a level of directory
lookup.

> The general issue of moving tables between tablespaces can be done from
> in the database.  I don't think it is reasonable to shut down the db to
> do that.  However, I can see moving tablespaces to different symlinked
> locations may require a shutdown.

Only if you insist on doing it outside the database using filesystem
tools.  Another way is to create a new tablespace in the desired new
location, then move the tables one-by-one to that new tablespace.

I suppose either one might be preferable depending on your access
patterns --- locking your most critical tables while they're being moved
might be as bad as a total shutdown.

			regards, tom lane