Alvaro Herrera wrote:
>>One generalization of this to nested transactions would be:
>>
>> SUBBEGIN [transactionname]
>> SUBCOMMIT [transactionname]
>> SUBABORT [transactionname]
>
>
> The only departure from the SAVEPOINT syntax is that you are able to
> "subcommit" a savepoint. Not sure how useful that is ...
One thing SUBCOMMIT [name] does allow is discarding savepoints / named
txns without rolling back their changes. That might be useful if we
allow nesting of names, e.g.:
SAVEPOINT save1 -- do work #1 SAVEPOINT save1 -- hides the earlier SAVEPOINT -- do work #2 SAVEPOINT
save2 -- do work #3 SUBCOMMIT save1 -- provisionally commits #2 and #3 to enclosing txn -- do work #4
ROLLBACKTO save1 -- rolls back #1, #2, #3, #4
Other than that.. I assume we want SUBBEGIN/SUBCOMMIT/SUBABORT
regardless of how we do savepoints. Since savepoints are a subset of
what you can do with nested transactions, it seems appropriate that
SUBBEGIN etc. can do everything that savepoints can -- i.e. naming of
savepoints/transactions. And then SUBCOMMIT [name] is just there for
completeness.
-O
