From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: Amit Langote <amitlangote09@gmail.com>,
        Justin Pryzby <pryzby@telsasoft.com>,
        "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: FailedAssertion("pd_idx == pinfo->nparts",
 File: "execPartition.c", Line: 1689)
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Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
	message dated "Wed, 05 Aug 2020 13:53:03 -0400"
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Date: Wed, 05 Aug 2020 14:21:59 -0400
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Robert Haas <robertmhaas@gmail.com> writes:
> On Wed, Aug 5, 2020 at 1:30 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I'm strongly tempted to convert the trailing Assert to an actual
>> test-and-elog, too, but didn't do so here.

> I was thinking about that, too. +1 for taking that step.

Will do.

In the longer term, it's annoying that we have no test methodology
for this other than "manually set a breakpoint here".  If we're going
to allow plan-relevant DDL changes to happen with less than full table
lock, I think we need to improve that.  I spent a little bit of time
just now trying to build an isolationtester case for this, and failed
completely.  So I wonder if we can create some sort of test module that
allows capture of a plan tree and then execution of that plan tree later
(even after relcache inval would normally have forced replanning).
Obviously that could not be a normal SQL-accessible feature, because
some types of invals would make the plan completely wrong, but for
testing purposes it'd be mighty helpful to check that a stale plan
still works.

			regards, tom lane