hash operator error

[robe]

On IRC velix mentioned this bug in PostGIS 3.5.0.

I haven't tested prior versions but I suspect is a regression.

To generate the error:

WITH lines AS (SELECT ST_GeomFromText('LINESTRING(1 2, 3 4)') AS geom
UNION ALL 
SELECT  ST_GeomFromText('LINESTRING(6 5, 7 8)') AS geom
)
SELECT t1.geom, t2.geom
FROM lines AS t1, lines AS t2
WHERE t1.geom <> t2.geom;

Error is - I think hash operator id might change

ERROR:  could not find hash function for hash operator 1192459 

[strk]

Interesting, I can reproduce with

POSTGIS="3.6.0dev 3.5.0-32-g511435a7d"

[pramsey]

New and exciting error. On 3.4 it's a different error. So this may have never worked, and is now just failing in a different way.

postgis34=# WITH lines AS (SELECT ST_GeomFromText('LINESTRING(1 2, 3 4)') AS geom
 UNION ALL 
  SELECT  ST_GeomFromText('LINESTRING(6 5, 7 8)') AS geom
 ) 
 SELECT t1.geom, t2.geom
 FROM lines AS t1, lines AS t2
 WHERE t1.geom <> t2.geom;

ERROR:  operator is not unique: geometry <> geometry
LINE 7: WHERE t1.geom <> t2.geom;                      ^
HINT:  Could not choose a best candidate operator. You might need to add explicit type casts.

[robe]

Replying to pramsey:

New and exciting error. On 3.4 it's a different error. So this may have never worked, and is now just failing in a different way.

postgis34=# WITH lines AS (SELECT ST_GeomFromText('LINESTRING(1 2, 3 4)') AS geom
 UNION ALL 
  SELECT  ST_GeomFromText('LINESTRING(6 5, 7 8)') AS geom
 ) 
 SELECT t1.geom, t2.geom
 FROM lines AS t1, lines AS t2
 WHERE t1.geom <> t2.geom;

ERROR:  operator is not unique: geometry <> geometry
LINE 7: WHERE t1.geom <> t2.geom;                      ^
HINT:  Could not choose a best candidate operator. You might need to add explicit type casts.

I think the addition of the operator you added in 3.5, that was the error we used to get

see ​https://git.osgeo.org/gitea/postgis/postgis/src/branch/stable-3.5/NEWS#L111

So I think the fix for #5175 is what is causing this error

[Paul Ramsey <pramsey@…>]

In 0b4dc6f/git:

Remove false guarantees of hashes/merges from ≠ operator, references #5815

[Paul Ramsey <pramsey@…>]

In 49df3d0/git:

Remove false guarantees of hashes/merges from ≠ operator, references #5815