Re: Transaction callback

Tom Lane wrote:
> "Thomas Hallgren" <thhal(at)mailblocks(dot)com> writes:
> > Ideally, I'd like a "beforeCompletion" that is executed prior to the start
> > of the commit process and a "afterCompletion" that is called when the
> > transaction is commited. The latter would have a status flag indicating if
> > status is "prepared" (to support 2-phase commits), "commited", or "rolled
> > back".
>
> And what exactly would this callback do?
>
> The transaction commit sequence is sufficiently delicate that I'm not
> interested in any proposals to call random user-written code in it.
> The notion of a post-commit callback is even more problematic --- what
> is it going to do at all? It cannot modify the database, and it cannot
> do anything that risks getting an error, which seems to leave mighty
> little scope for useful activity.

Why can't we call the callback before we commit so it can modify the
database?

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