On Fri, Dec 27, 2019 at 10:29:15PM -0500, Tom Lane wrote: > David Fetter <da...@fetter.org> writes: > > While noodling around with an upcoming patch to remove user-modifiable > > RULEs, I noticed that WHEN conditions were disallowed from INSTEAD OF > > triggers for no discernible reason. This patch removes that > > restriction. > > This seems like a remarkably bad idea. The point of an INSTEAD OF > trigger is that it is guaranteed to handle the operation. What's > the system supposed to do with rows the trigger doesn't handle?
Nothing. Why would it be different from the other forms of WHEN in triggers? > I notice that your patch doesn't even bother to test what happens, > but I'd argue that whatever it is, it's wrong. If you think that > "do nothing" or "throw an error" is appropriate, you can code that > inside the trigger. It's not PG's charter to make such a decision. If that's the case, why do we have WHEN for triggers at all? I'm just working toward make them more consistent. From a UX perspective, it's a lot simpler and clearer to do this in the trigger declaration than it is in the body. > PS: I think your chances of removing rules are not good, either. I suspect I have a lot of company in my view of user-modifiable rewrite rules as an experiment we can finally discontinue in view of its decisive results. Best, David. -- David Fetter <david(at)fetter(dot)org> http://fetter.org/ Phone: +1 415 235 3778 Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate
