On Thu, Nov 17, 2005 at 10:15:30AM -0500, Stephen Frost wrote:
> REPLACE/INSERT ON DUPLICATE UPDATE appears to essentially be a
> transaction which is supposed to not fail but instead do locking to
> ensure that it doesn't fail. This requires predicate locking to be
> efficient because you want to tell the concurrent transaction "if you
> have the same key as me, just wait a second and you can do an update
> 'cause I'm going to create the key if it doesn't exist before I'm done".
Is the requirement for predicate locking, over and above a unique
constraint on an index that involves the record key, to deal with
the scenario of two inserts executing at the same time, both before
commit?
Cheers,
mark
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