Horton

Re: [PATCH] Improve geometric types

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: emre@hasegeli.com, Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>, Thomas Munro <thomas.munro@enterprisedb.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2018-09-26T22:48:47Z
Lists: pgsql-hackers 
Tomas Vondra <tomas.vondra@2ndquadrant.com> writes:
> On 09/26/2018 06:45 PM, Tom Lane wrote:
>> gaur's not happy, but rather surprisingly, it looks like we're
>> mostly OK elsewhere.  Do you need me to trace down exactly what's
>> going wrong on gaur?

> Or you could just try doing
>     select '(0,0)'::point * '(-3,4)'::point;
> If this is what's going on, I'd say the best solution is to make it
> produce (0,0) everywhere, so that we don't expect -0.0 anywhere.

Actually, it seems simpler than that: gaur produces plus zero already
from the multiplication:

regression=# select '-3'::float8 * '0'::float8;
 ?column? 
----------
        0
(1 row)

whereas I get -0 elsewhere.  I'm surprised that this doesn't create
more widely-visible regression failures, but there you have it.

> We could do that either by adding the == 0.0 check to yet another place,
> or to point_construct() directly. Adding it to point_construct() means
> we'll pay the price always, but I guess there are few paths where we
> know we don't need it. And if we add it to many places it's likely about
> as expensive as adding it to point_construct.

If gaur is the only machine showing this failure, which seems more
likely by the hour, I'm not sure that we should give up performance
across-the-board to make it happy.  Perhaps a variant expected-file
is a better answer; or we could remove these specific test cases.

Anyway, I'd counsel doing nothing for a day or so, till the buildfarm
breakage from the strerror/snprintf changes clears up.  Then we'll
have a better idea of whether any other machines are affected.

			regards, tom lane

Commits

  1. Improve test coverage of geometric types

  2. Fix problems in handling the line data type

  3. Use the built-in float datatypes to implement geometric types

  4. Remove remaining GEODEBUG references from geo_ops.c

  5. Provide separate header file for built-in float types

  6. Refactor geometric functions and operators

  7. Fix crash in close_ps() for NaN input coordinates.

  8. Fix GiST index build for NaN values in geometric types.

  9. Enable building with Visual Studion 2013.

  10. Suppress -0 in the C field of lines computed by line_construct_pts().