Re: Nested Transactions, Abort All

Alvaro Herrera wrote:
> 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
implicitlys2
 

We 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