Re: Per-function GUC settings: trickier than it looked

Michael Paesold <mpaesold(at)gmx(dot)at> writes:
> Florian G. Pflug wrote:
>> Hm... could we still have "SET TRANSACTION" as a synonym for "SET LOCAL"?
>> That would blend nicely with "SET TRANSACTION ISOLATION LEVEL" and
>> "SET TRANSACTION READ ONLY".

> I don't think it's a very good idea to make SET TRANSACTION an alias for
> SET LOCAL, because SET TRANSACTION has already got its own meaning in the
> SQL spec - it sets transaction modes.

Yeah --- I'm not sure we could even do it without getting shift/reduce
conflicts in bison.

There is some attraction to the idea of keeping SET LOCAL's current
behavior and inventing a third form of SET that has the
lasts-till-end-of-current-main-transaction behavior. However
(1) we'd have to pick some other keyword than TRANSACTION;
(2) I still don't see how to document SET LOCAL's current behavior
without introducing the concept of "subtransaction" into it, and
I think we shouldn't do that.

Basically my perspective on SET LOCAL is that its current behavior is a
bug, and even though it's been that way for a couple major releases now,
it's still something we oughta fix while we are busy whacking that part
of the code around. Florian's example with SET TRANSACTION READ ONLY
proves that it's a bug --- RELEASE is not defined to change any
transaction modes.

regards, tom lane