From: | Douglas McNaught <doug(at)mcnaught(dot)org> |
---|---|
To: | Joseph Shraibman <jks(at)selectacast(dot)net> |
Cc: | Postgresql-General <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: blocking INSERTs |
Date: | 2005-06-08 03:48:35 |
Message-ID: | m2r7fd1pbg.fsf@Douglas-McNaughts-Powerbook.local |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
Joseph Shraibman <jks(at)selectacast(dot)net> writes:
> I want to do the following:
>
> BEGIN;
> SELECT ... FROM table WHERE a = 1 FOR UPDATE;
> UPDATE table SET ... WHERE a = 1;
> if that resturns zero then
> INSERT INTO table (...) VALUES (...);
> END;
>
> The problem is that I need to avoid race conditions. Sometimes I get
> primary key exceptions on the INSERT.
>
> I think I need to lock the table in share mode to keep inserts from
> happening, but that blocks vacuums, and blocked vacuums block other
> things behind them. So how do I get around this?
Ummm... Don't lock the table for very long? :) If you commit
your transaction promptly then the table will be unlocked again.
-Doug
From | Date | Subject | |
---|---|---|---|
Next Message | Dinesh Pandey | 2005-06-08 05:25:01 | Postgres 8.0.1 configure failed |
Previous Message | Joseph Shraibman | 2005-06-08 03:31:54 | blocking INSERTs |