> Another thought: do we need WAL UNDO at all to implement savepoints?
> Is there some way we could do them like nested transactions, wherein
> each savepoint-to-savepoint segment is given its own transaction number?
> Committing multiple xact IDs at once might be a little tricky, but it
> seems like a narrow, soluble problem. Implementing UNDO without
> creating lots of performance issues looks a lot harder.
I am confused why we can't implement subtransactions as part of our
command counter? The counter is already 4 bytes long. Couldn't we
rollback to counter number X-10?
-- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610)
853-3000+ If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill,
Pennsylvania19026
