Re: CREATE TABLE .. PARTITION OF fails to preserve tgenabled for inherited row triggers

On Tue, Oct 20, 2020 at 03:56:30PM -0400, Tom Lane wrote:
> Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> writes:
> > Hmm, next question: should we backpatch a fix for this? (This applies
> > all the way back to 11.) If we do, then we would change behavior of
> > partition creation. It's hard to see that the current behavior is
> > desirable ... and I think anybody who would have come across this, would
> > wish it behaved the other way. But still -- it would definitely be a
> > behavior change.
>
> The behavior change seems like it'd be an improvement in a vacuum,
> but I wonder how it would interact with catalog contents left behind
> by the old misbehavior. Also, would we expect pg_dump to try to do
> anything to clean up the mess? If so, allowing a back branch to have
> had more than one behavior would complicate that greatly.

I don't think there's a problem with catalog content ?
I think it's fine if there's an enabled child trigger inheriting from a
disabled parent? This changes the initial tgenabled for new partitions.

The old catalog state is still possible - it's what you'd get if you did
CREATE TABLE child PARTITION OF..; ALTER TABLE child DISABLE TRIGGER.

I don't think pg_dump needs to do anyting special, since the restore will now
do what's wanted without added commands. Note that pg_dump switched from
"PARTITION OF" to "ATTACH PARTITION" at commit 33a53130a. This would handles
both on the server side.

However...it looks like pg_dump should ALTER the child trigger state if it
differ from its parent. Or maybe it needs to CREATE child triggers with the
proper state before attaching the child table ?

--
Justin