Re: Fix typo function circle_same (src/backend/utils/adt/geo_ops.c) - Mailing list pgsql-hackers

From Daniel Gustafsson
Subject Re: Fix typo function circle_same (src/backend/utils/adt/geo_ops.c)
Date
Msg-id 99551E55-5322-4023-BA6C-ADD3C9E90CFD@yesql.se
Whole thread Raw
In response to Re: Fix typo function circle_same (src/backend/utils/adt/geo_ops.c)  (Julien Rouhaud <rjuju123@gmail.com>)
Responses Re: Fix typo function circle_same (src/backend/utils/adt/geo_ops.c)
List pgsql-hackers
> On 3 Sep 2022, at 09:36, Julien Rouhaud <rjuju123@gmail.com> wrote:

> Yeah, there are unfortunately a lot of problems around those and NaN, with
> multiple reports in the past (I recall [1] and [2] but there were others).

NaNs are indeed incredibly complicated, but I think we are sort of in a good
place here given it's testing for equality in floats.  The commit message of
c4c34008854654279ec30067d72fc5d174d2f42f carries an explanation:

    The float datatypes consider NaNs values to be equal and greater than
    all non-NaN values.  This change considers NaNs equal only for equality
    operators.  The placement operators, contains, overlaps, left/right of
    etc.  continue to return false when NaNs are involved.

From testing and reading I believe the fix in this thread is correct, but since
NaNs are involved I will take another look at this with fresh eyes before going
ahead.

--
Daniel Gustafsson        https://vmware.com/




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