Re: Floating point comparison inconsistencies of the geometric types

Hello,

At Thu, 29 Sep 2016 10:37:30 +0200, Emre Hasegeli <emre(at)hasegeli(dot)com> wrote in <CAE2gYzxijWKwJ-ZPD--QHM+SxMd+vL_81_3Xt0spnCbsqFH=Ug(at)mail(dot)gmail(dot)com>
> > regression=# select 'I- 580 Ramp' < 'I- 580/I-680 Ramp';
> > ?column?
> > ----------
> > t
> > (1 row)
>
> on the Linux server I am testing, it is not:
>
> > regression=# select 'I- 580 Ramp' < 'I- 580/I-680 Ramp';
> > ?column?
> > ----------
> > f
> > (1 row)
>
> The later should be the case on your environment as the test was also
> failing for you. This is not consistent with the expected test
> result. Do you know how this test can still pass on the master?

Perhaps you ran the test under the environment LC_COLLATE (or
LANG) of something other than C. The reson for the result is
collation. The following returns expected result.

=# select 'I- 580 Ramp' < ('I- 580/I-680 Ramp' COLLATE "C");
?column?
----------
t
(1 row)

For a reason I don't know, say, en_US locale behaves in an
unintuitive way.

regression=# select ' ' < ('/' COLLATE "en_US"), ' x' < ('/a' COLLATE "en_US");
?column? | ?column?
----------+----------
t | f
(1 row)

Returning to the issue, the following query should give you the
expected result.

SELECT name, #thepath FROM iexit ORDER BY name COLLATE "C", 2;

regards,

--
Kyotaro Horiguchi
NTT Open Source Software Center