> I don't know of any SQL databases that allow non-blocking lock requests.
>
Informix has all kinds of non blocking locks:return "record locked" at oncereturn "record locked" after a specified
timeoutwaitfor the lock indefinitely
To supply this behavior it has the following statements:set lock mode to not wait; -- return immediately with error
-- if record already lockedset lock mode to wait 10; -- wait at max 10 secondsset lock mode to wait;
-- wait indefinitely
Dirty read isolation has actually nothing to do with the wanted feature.
Andreas