Re: Question: test "aggregates" failed in 32-bit machine

From: Peter Geoghegan <pg(at)bowt(dot)ie>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Tomas Vondra <tomas(dot)vondra(at)enterprisedb(dot)com>, "kuroda(dot)hayato(at)fujitsu(dot)com" <kuroda(dot)hayato(at)fujitsu(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: Question: test "aggregates" failed in 32-bit machine
Date: 2022-10-01 19:26:30
Message-ID: CAH2-Wzm8+4=zopa0Ee=TbeC12_b7xYH63sCc0O2EMZC=nPC98w@mail.gmail.com
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On Sat, Oct 1, 2022 at 12:14 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> I spent some time today looking into the question of what our qsort
> code actually does. I wrote a quick-n-dirty little test module
> (attached) to measure the number of comparisons qsort really uses
> for assorted sample inputs.

Reminds me of the other sort testing program that you wrote when the
B&M code first went in:

https://www.postgresql.org/message-id/18732.1142967137@sss.pgh.pa.us

This was notable for recreating the tests from the original B&M paper.
The paper uses various types of test inputs with characteristics that
were challenging to the implementation and worth specifically getting
right. For example, "saw tooth" input.

--
Peter Geoghegan

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