Re: Regression Failure: CURRENT SOURCES/union&join

From: Larry Rosenman <ler(at)lerctr(dot)org>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Regression Failure: CURRENT SOURCES/union&join
Date: 2003-10-31 21:51:29
Message-ID: 370180000.1067637089@lerlaptop-red.iadfw.net
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--On Friday, October 31, 2003 16:49:17 -0500 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
wrote:

> Larry Rosenman <ler(at)lerctr(dot)org> writes:
>> *** ./expected/union.out Thu Oct 9 20:49:31 2003
>> --- ./results/union.out Fri Oct 31 15:15:50 2003
>> ***************
>> *** 106,112 ****
>> two
>> -----
>> 1.1
>> ! 2
>> (2 rows)
>
>> SELECT 1.1 AS three UNION SELECT 2 UNION ALL SELECT 2;
>> --- 106,112 ----
>> two
>> -----
>> 1.1
>> ! 2.0
>> (2 rows)
>
> I think this is just a platform-specific difference in the behavior of
> qsort(). Numeric "2" and "2.0" print differently, but they are equal
> according to the comparison operators, so it's mostly luck of the draw
> which one is selected for output.
>
> The original coding of this regression test expected that these values
> would be interpreted as float8, wherein there is no difference between
> "2" and "2.0". I'm kind of inclined to change the test back to using
> float8 so we don't see more of these reports.
>
>> *** ./expected/join.out Thu Oct 9 20:49:31 2003
>> --- ./results/join.out Fri Oct 31 15:15:51 2003
>> [ row ordering differences ]
>
> This also looks like platform-specific behavior --- the differences are
> in the sort ordering of rows with equal keys.
OK. This makes sense. SCO made improvements in the qsort() routine in
an update I applied Wednesday. (And, it had to do with equal key
processing).

137. The qsort() routine was reworked to increase performance, especially
when presented with lots of "equal" data items.
fz527984 fz528071

Modulo these diffs, we now pass all tests on UnixWare.

Any chance of the patch I posted to -patches being applied for 7.4?

LER

>
> regards, tom lane

--
Larry Rosenman http://www.lerctr.org/~ler
Phone: +1 972-414-9812 E-Mail: ler(at)lerctr(dot)org
US Mail: 1905 Steamboat Springs Drive, Garland, TX 75044-6749

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