On Sat, Jul 10, 2004 at 09:46:56AM +1200, Oliver Jowett wrote:
Alvaro Herrera wrote:
We can't actually release anything (commit the subtransactions), because they may be savepoints established after that point, and they are logically "inside" the previously established ones. At RELEASE we can't really release -- we just lose the name and thus the opportunity to rollback to it.
The 2003 draft claims that RELEASE SAVEPOINT invalidates savepoints subsequent to the RELEASE:
(that should read "subsequent to the released savepoint")
In our case, invalidating a savepoint does not mean we can release its resources. We can only do that if it's the latest defined savepoint.
I don't understand why this is true if the invalidation comes from a RELEASE statement. I understand the problems with savepoint name reuse invalidating an earlier savepoint -- we do have to keep the earlier txn open in that case.
Say I have:
SAVEPOINT s1 -- work 1 SAVEPOINT s2 -- work 2 RELEASE SAVEPOINT s1 -- Invalidates s1 and s2
Can't we translate that to:
begin subtransaction s1
-- work 1
begin subtransaction s2
-- work 2
commit subtransaction s1 -- and implicitly s2We don't need to keep subtransaction s2 open -- we will never need to roll it back as the RELEASE of s1 invalidates it.
What am I missing?
-O
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