Martijn van Oosterhout wrote: -- Start of PGP signed section. > On Wed, Nov 16, 2005 at 11:37:46AM -0500, Bruce Momjian wrote: > > > > Interesting approach. Actually, we could tell the user they have to use > > BEGIN;LOCK tab before doing MERGE, and throw an error if we don't > > already have a table lock. > > The bit I'm still missing is why there needs to be a lock at all. The > SQL standard doesn't say anywhere that concurrent MERGE operations > can't conflict. It seems to me that standard visibility rules apply. If > neither MERGE statement can see the results of the other, then they > will both INSERT. If you don't have a UNIQUE constraint to prevent this > then what's the problem?
I assume they want MERGE because they don't want duplicates. If they don't care, they would have used INSERT. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073 ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
