Date: Fri, 1 Jul 2022 19:07:04 -0500
From: Justin Pryzby <pryzby@telsasoft.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Michael Paquier <michael@paquier.xyz>,
	Robert Haas <robertmhaas@gmail.com>,
	Tomas Vondra <tomas.vondra@enterprisedb.com>,
	pgsql-hackers@postgresql.org
Subject: Re: should check interrupts in BuildRelationExtStatistics ?
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On Fri, Jul 01, 2022 at 07:19:11PM -0400, Tom Lane wrote:
> I tried interrupting at a random point and then stepping, and
> look what I hit after just a couple of steps:

I'd come up with the trick of setting
  SET backtrace_functions='ProcessInterrupts';

> That, um, piqued my interest.  After a bit of digging,
> I modestly propose the attached.  I'm not sure if it's
> okay to back-patch this, because maybe someone out there
> is relying on qsort() to be incapable of throwing an error
> --- but it'd solve the problem at hand and a bunch of other
> issues of the same ilk.

Confirmed this fixes the 3 types of extended stats, at least for the example
cases I made.

If it's okay to backpatch, v14 seems adequate since the problem is more
prominent with expressional statistics (I'm sure that's why I hit it) ...
otherwise v15 would do.

-- 
Justin