Re: schema/db design wrt performance

On Thu, Jan 16, 2003 at 08:34:38AM -0600, Ron Johnson wrote:
> On Thu, 2003-01-16 at 08:20, Andrew Sullivan wrote:

> > If a user has multiple connections and charges things to the same
> > account in more than one connection at the same time, the
> > transactions will have to be processed, effectively, in series: each
> > one will have to wait for another to commit in order to complete.
>
> This is true even though the default transaction mode is
> READ COMMITTED?

Yes.  Remember, _both_ of these are doing SELECT. . .FOR UPDATE.
Which means they both try to lock the corresponding record.  But they
can't _both_ lock the same record; that's what the lock prevents.

A

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