Re: INSERT ON DUPLICATE KEY UPDATE
От | Robert Treat |
---|---|
Тема | Re: INSERT ON DUPLICATE KEY UPDATE |
Дата | |
Msg-id | 1087594345.2111.78.camel@camel обсуждение исходный текст |
Ответ на | Re: INSERT ON DUPLICATE KEY UPDATE (jseymour@linxnet.com (Jim Seymour)) |
Список | 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
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