Horton

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

Justin Pryzby <pryzby@telsasoft.com>

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From: Justin Pryzby <pryzby@telsasoft.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@postgresql.org, Amit Langote <amitlangote09@gmail.com>
Date: 2020-10-21T11:54:53Z
Lists: pgsql-hackers

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On Tue, Oct 20, 2020 at 09:54:53PM -0300, Alvaro Herrera wrote:
> On 2020-Oct-20, Justin Pryzby wrote:
> > On Tue, Oct 20, 2020 at 03:56:30PM -0400, Tom Lane wrote:
> > > Alvaro Herrera <alvherre@alvh.no-ip.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.
> 
> I don't think we'd need to do anything special here ... particularly
> considering the discovery that pg_dump does not preserve the disable
> status of trigger on partitions:
> 
> > 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 ?
> 
> I guess *something* needs to be done, but I'm not clear on what it is.
> Creating the trigger on partition beforehand does not work: an error is
> raised on attach that the trigger already exists.
> 
> The only way I see to do this, is to have pg_dump extract tgenabled for

I came up with this, which probably needs more than a little finesse.

-- 
Justin

Commits

  1. Fix pg_dump for disabled triggers on partitioned tables

  2. Preserve firing-on state when cloning row triggers to partitions

  3. Fix ALTER TABLE .. ENABLE/DISABLE TRIGGER recursion

  4. psql \d: Display table where trigger is defined, if inherited

  5. Fix cloning of row triggers to sub-partitions

  6. Make pg_dump emit ATTACH PARTITION instead of PARTITION OF (reprise)