Re: Two features left

Jon Swinth <jswinth@atomicpc.com> writes:
> Ok, so it looks like your nested transactions and savepoints are really the
> same thing.  The question is, are you going to change the way SQL exceptions
> are handled so that simply abort that SQL statement don't require a rollback?
> With your enhancement, it sounds like calling BEGIN before each SQL statement
> could acheive what I am asking for, but the issue is existing applications
> will not expect to have to do so.

Au contraire: existing PG applications would be broken completely if the
behavior of error rollback suddenly changes.

There is also an efficiency issue: nested transactions will not be free,
and one should not be forced to pay for them when not needed.

It might be reasonable to have a GUC parameter that enables an implicit
subtransaction around each command in a transaction block (perhaps only
at the topmost nesting level?) --- but it won't become the default
behavior in the foreseeable future.

Note also that Bruce has no expectation of supporting subtransactions
within a function call; that opens a much larger can of worms than what
he's already getting into.  So this facility would only be available at
the interactive-command level.

            regards, tom lane