Re: GSOC13 proposal - extend RETURNING syntax

On 2013-10-03 20:51:08 -0400, Robert Haas wrote:
> On Thu, Oct 3, 2013 at 7:54 PM, Karol Trzcionka <karlikt@gmail.com> wrote:
> > Compare EXPLAIN ANALYZE VERBOSE on your statement and on "patched"
> > workflow. I can see significant difference. And your "after" returns the
> > value after whole the work (after trigger fired) as I know (I don't know
> > if it is needed or not, I only point at the difference).
> 
> Sure, I'm not saying we should implement it that way.  I'm just
> pointing out that the ability already exists, at the executor level,
> to return either tuple.  So I think the executor itself shouldn't need
> to be changed; it's just a matter of getting the correct plan tree to
> pop out.

Note what pullups ExecDelete is doing to return the old tuple
though... So, based on precedent special executor support is not an
unlikely thing to be required for a proper implemenation. As Marko
mentions, any trivial implementation not doing playing dirty like that
will refer to the wrong version of the tuple.

Greetings,

Andres Freund

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