Barry Lind wrote: > I agree with Simon's comments. And to them I would add: I had assumed > that the requirements for 'nested transactions' was following some > standard definition or specification (i.e. the ANSI SQL spec). But from > what I can tell, we are rolling our own definition here, not following a > specification or standard, and not following any of the other major > commercial databases lead. > > I think venturing out on our own and inventing new symantics for > transactions and sql syntax to support them without giving this a lot of > thought is bound to lead to problems. > > Perhaps I am completely wrong here and there is a clear standard or spec > that is being implemented, if so, please let me know what that is as it > would help me in better understanding this patch. > > I have been reviewing what Oracle does in this area and it doesn't at > all resemble what this patch is exposing (especially as far as syntax > goes). I plan to look at DB2 and MSSQL next.
I realized about three weeks ago that our syntax for nested transactions doesn't follow anyone else's method. I think I might be the person who suggested the idea because it seemed more logical to me to allow BEGIN;BEGIN;COMMIT;COMMIT rather than naming arbitrary locations as savepoints and doing a rollback to that savepoint name. And consider this case: BEGIN; ... SAVEPOINT x; SELECT func_call(); SELECT func_call(); COMMIT; Now if func_call has a savepoint, it is really nested because it can't know whether the savepoint X will be used to roll back, so its status is dependent on the status of X. Now, if we used savepoints in func_call, what happens in the second function call when we define a savepoint with the same name? I assume we overwrite the original, but using nested transaction syntax seems much clearer. Basically, we have to implement this in a nested way. Once it is done, we can add the window dressing to support the ANSI syntax. -- Bruce Momjian | http://candle.pha.pa.us [EMAIL PROTECTED] | (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 4: Don't 'kill -9' the postmaster