Re: INSERT ON DUPLICATE KEY UPDATE - Mailing list pgsql-general

From Robert Treat
Subject Re: INSERT ON DUPLICATE KEY UPDATE
Date
Msg-id 1087594345.2111.78.camel@camel
Whole thread Raw
In response to Re: INSERT ON DUPLICATE KEY UPDATE  (jseymour@linxnet.com (Jim Seymour))
List pgsql-general
On Fri, 2004-06-18 at 16:41, Jim Seymour wrote:
> Robert Treat <xzilla@users.sourceforge.net> wrote:
> >
> [snip]
> >
> > IIRC the main downside to the select/update method is it introduces a
> > race condition that can only be solved by locking the table; not an
> > issue for most my$ql apps but would be frowned upon by most postgresql
> > users.
> [snip]
>
> One way around the race condition is to insert and, if the insert
> fails, do an update.  If that fails, then something is actually wrong.
>
> One caveat regarding the above solution: Even when an insert fails, if
> there's a column with a sequence in it, that sequence will be
> incremented nonetheless.
>

The other being that you can't do that within a transaction in
postgresql. Course that should change if alvaro gets nested transactions
done for 7.5. (go alvaro go!)

Robert Treat
--
Build A Brighter Lamp :: Linux Apache {middleware} PostgreSQL


pgsql-general by date:

Previous
From: Robert Treat
Date:
Subject: Re: INSERT ON DUPLICATE KEY UPDATE
Next
From: DeJuan Jackson
Date:
Subject: Re: Trigger to update records out of memory