From: Tom Lane <tgl@sss.pgh.pa.us>
To: Mark Dilger <mark.dilger@enterprisedb.com>
cc: Robert Haas <robertmhaas@gmail.com>, Peter Geoghegan <pg@bowt.ie>,
        "Andrey M. Borodin" <x4mmm@yandex-team.ru>,
        Stephen Frost <sfrost@snowman.net>,
        Michael Paquier <michael@paquier.xyz>, Amul Sul <sulamul@gmail.com>,
        Dilip Kumar <dilipbalaut@gmail.com>,
        Andres Freund <andres@anarazel.de>,
        PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: new heapcheck contrib module
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Comments: In-reply-to Mark Dilger <mark.dilger@enterprisedb.com>
	message dated "Fri, 23 Oct 2020 13:52:18 -0700"
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Date: Fri, 23 Oct 2020 19:12:41 -0400
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Mark Dilger <mark.dilger@enterprisedb.com> writes:
> You certainly appear to be right about that.  I've added the extra check=
s, and extended the regression test to include them.  Patch attached.

Pushed with some more fooling about.  The "bit reversal" idea is not
a sufficient guide to picking values that will hit all the code checks.
For instance, I was seeing out-of-range warnings on one endianness and
not the other because on the other one the maxalign check rejected the
value first.  I ended up manually tweaking the corruption patterns
until they hit all the tests on both endiannesses.  Pretty much the
opposite of black-box testing, but it's not like our notions of line
pointer layout are going to change anytime soon.

I made some logic rearrangements in the C code, too.

			regards, tom lane