Re: version locking details for update ... where ...

[Peter Brawley]

If, on a modest modern machine, you run, say, five simultaneous threads of a hundred such updates on one row, you'll get a rollback rate of maybe 40%; read committed vs repeatable read won't make much difference to that rate, but adding For Update to the Select will get rid of most of them. Still, you'll need to add code to retry the transaction when it fails or deadlocks.