Ted Toth <txtoth@gmail.com> writes:
> I think you are right in that the trigger doesn't change the row being
> updated (which is good) but it also updates another table and that's what
> I'd actually like to avoid on update.
Probably need to put that in an AFTER trigger, then. By definition,
BEFORE triggers don't really know whether the insert is going to
happen. This doesn't even require use of upsert to cause a problem:
a later BEFORE trigger could prevent the insertion, or change what
gets inserted.
regards, tom lane