Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> I suggest that the current behavior was designed for the case of
> independent concurrent updates, and you have not made a good
> argument for changing that. What does make sense to me, in light
> of these examples, is to complain if a BEFORE trigger modifies the
> row "itself" (including indirect updates). IOW, at conclusion of
> trigger firing (I see no need to do it for each trigger), check to
> see if the target row has been outdated *by the current
> transaction*, and throw error if not.
>
> And, if you accept the statement of the fix like that, then
> actually there is no performance hit because there is no need to
> introduce new tests. All we have to do is start treating
> HeapTupleSelfUpdated result from heap_update or heap_delete as an
> error case instead of an okay-do-nothing case. There doesn't even
> need to be an explicit check that this was caused by a trigger,
> because AFAICS there isn't any other possibility.
I think that's pretty much what my previously posted patches did.
Here's a slightly modified one, based on Florian's feedback. Is
this what you had in mind, or am I misunderstanding?
-Kevin