Re: Nested transactions RFC

Manfred Koizar <mkoi-pg@aon.at> writes:
> A *stack* of _active_ transaction numbers is not sufficient, we need
> the whole *tree* of _all_ transactions belonging to the current top
> level transaction.  This is, want I wanted to model in my pg_subtrans
> "table".  And pg_subtrans cannot be a private structure, because it
> has to be inspected by other transactions too (cf. example above).

Hmm.  This seems to me to be vastly overdesigning the feature.  I've
never yet seen a practical application for more than one level of
subtransaction, so I question whether we should buy into a substantially
more complex implementation to support the more general case.

> Is this really related to subtransactions?  The current behaviour is,
> that an error not only aborts the offending command, but the whole
> (top level) transaction.  My proposal doesn't change anything
> regarding this.

Every single application that I've seen for subtransactions is all about
error recovery.  If we don't fix that then there's no point.

> You have quoted only small parts of my posting.

I don't believe in quoting whole postings, only enough to remind people
what it was I'm responding to.
        regards, tom lane