Re: WIP: push AFTER-trigger execution into ModifyTable node

Marko Tiikkaja <marko(dot)tiikkaja(at)cs(dot)helsinki(dot)fi> writes:
> Like we've discussed before, WITH (.. RETURNING ..) is probably most
> useful for moving rows from one table to another. When you're moving a
> lot of rows around, there's some point where I believe this execution
> strategy will be a lot slower than the traditional approach due to
> storing the RETURNING results on disk. I've been thinking that in some
> cases we could inline the CTE for this to actually be a quite
> significant performance benefit, so I'm not too fancy about the approach
> you're suggesting.

Well, this is what we need to nail down *now*. Are we going to say that
use of WITH(RETURNING) means you forfeit all guarantees about order of
trigger firing? Short of that, I don't believe that it is sane to think
about pipelining such things. And if we do do that, it sounds like a
security hole to me, because the owner of the trigger isn't the one who
agreed to forfeit predictability.

regards, tom lane