[postgis-devel] EMPTY and Indexes

[Regina Obe]

Can we throw in some NaNs in our coordinates to amplify the fun factor :)

> -----Original Message-----
> From: postgis-devel [mailto:postgis-devel-bounces at lists.osgeo.org] On
> Behalf Of Paul Ramsey
> Sent: Monday, March 23, 2020 11:37 AM
> To: PostGIS Development Discussion <postgis-devel at lists.osgeo.org>
> Subject: [postgis-devel] EMPTY and Indexes
> 
> Found this little paragraph in the PgSQL docs:
> 
> "Note: In most implementations of the "not-a-number" concept, NaN is not
> considered equal to any other numeric value (including NaN). In order to
> allow numeric values to be sorted and used in tree-based indexes,
> PostgreSQL treats NaN values as equal, and greater than all non-NaN
> values."
> 
> Our handling of EMPTY in indexes is still inconsistent and probably really bad.
> I think this PgSQL approach would work much better. Basically any EMPTY
> could be considered over-right of any other box. That would drop all empties
> neatly into one leaf of the tree, while allowing the = operator to still *work*
> and retrieve empty values in an index scan.
> 
> Nan is kind of fun.
> 
> select 'NaN'::float8 <= 'NaN'::float8;
> select 'NaN'::float8 = 0;
> select 'NaN'::float8 > 100000000000000000000; select 'NaN'::float8 >
> 'Inf'::float8;
> 
> 
> 
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