Re: backend crash on DELETE, reproducible locally

Karsten Hilbert <Karsten(dot)Hilbert(at)gmx(dot)net> writes:
> On Thu, Nov 01, 2018 at 11:43:56AM -0400, Tom Lane wrote:
>> Yeah, apparently we've passed a null OLD tuple to an RI_FKey_cascade_del
>> trigger, which surely shouldn't happen. It'd be interesting to look at
>> the set of triggers on this table. I don't entirely trust psql's \d
>> to show us reality if there's something screwed up about the triggers,
>> so in addition to \d output, could we see
>> select * from pg_trigger where tgrelid = 'ref.auto_hint'::regclass;

> [ pretty normal-looking trigger entries ]

I was feeling baffled about this, but it suddenly occurs to me that maybe
the bug fixed in 040a1df61/372102b81 explains this. If the particular
tuple you're trying to delete predates the last ALTER TABLE ADD COLUMN
operation on the table, then this bug would result in t_self getting
set to "invalid", which'd cause AfterTriggerSaveEvent to save "ate_ctid1"
as "invalid", which'd lead to a null tuple getting passed when the trigger
eventually gets invoked.

regards, tom lane