On Fri, Jan 14, 2005 at 08:49:24PM +0100, PFC wrote: > the auto-expiration cron > job, I must also expire ALL his open chatroom connections. > INSERT INTO archive (...) SELECT ... FROM active WHERE user_id = ...; > DELETE FROM active WHERE user_id = ...; > > Now, if the user inserts a connection between the two queries above, the > thing will fail (the > connection will just be deleted). I know that there are many ways to do it > right :
Why not just do it in a single transaction? I don't think you need to use SERIALIZABLE at all, I think normal read-committed mode will do what you want, no? BEGIN; INSERT INTO archive (...) SELECT ... FROM active WHERE user_id = ...; DELETE FROM active WHERE user_id = ...; COMMIT; The DELETE can only delete the rows returned by the select, that's the whole point of transactions... Hope this helps, -- Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/ > Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a > tool for doing 5% of the work and then sitting around waiting for someone > else to do the other 95% so you can sue them.
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