From: Markus Schaber <schabios@logi-track.com>
To: pgsql-sql@postgresql.org
Subject: Re: Move table between schemas
Date: Sat, 20 Nov 2004 11:44:11 +0100
Message-ID: <20041120114411.28c05fcf@kingfisher.intern.logi-track.com> (raw)
In-Reply-To: <20041116110538.GA15247@phlogiston.dyndns.org>
References: <20041116100234.635fcd7e@kingfisher.intern.logi-track.com>
<20041116110538.GA15247@phlogiston.dyndns.org>
Hi, Andrew,
On Tue, 16 Nov 2004 06:05:38 -0500
Andrew Sullivan <ajs@crankycanuck.ca> wrote:
> > Is there an easy way to move a table to another schema in PostgreSQL 7.4?
> >
> > ALTER TABLE and ALTER SCHEMA don't have this options.
>
> CREATE TABLE newschema.newtable AS SELECT * FROM oldschema.oldtable
> oughta work.
This has several drawbacks I can see for now:
- For large tables (some Gigs of data), this needs a long time and
produces heavy I/O load on the server.
- You need twice the disk space until you can delete the old table.
- Indices, triggers, sequences and constraints are not transferred. When
the target schema is first in the search path of the application, this
means that the application works on an incomplete table until I finished
the transition..
- It does not automatically convert views or foreign key constraints
that point to the table.
- The operation is not atomic, thus there may be inserts and updates
into the old table that get lost while the "CREATE...SELECT...;DROP
TABLE...;" runs.
Is there any (possibly ugly, fiddling with system tables) atomic way to
move a table between schemas? It should not be much more difficult
compared to e. G. renaming a table to implement this, so I couuld not
imagine this does not exist until I tried to find out how to do it.
Thanks,
markus
--
markus schaber | dipl. informatiker
logi-track ag | rennweg 14-16 | ch 8001 zürich
phone +41-43-888 62 52 | fax +41-43-888 62 53
mailto:schabios@logi-track.com | www.logi-track.com
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To: pgsql-sql@postgresql.org
Cc: schabios@logi-track.com
Subject: Re: Move table between schemas
In-Reply-To: <20041120114411.28c05fcf@kingfisher.intern.logi-track.com>
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