[jira] [Created] (HIVE-11174) Hive does not treat floating point signed zeros as equal (-0.0 should equal 0.0 according to IEEE floating point spec)

[Lenni Kuff (JIRA)]

Lenni Kuff created HIVE-11174:
---------------------------------

             Summary: Hive does not treat floating point signed zeros as equal 
(-0.0 should equal 0.0 according to IEEE floating point spec) 
                 Key: HIVE-11174
                 URL: https://issues.apache.org/jira/browse/HIVE-11174
             Project: Hive
          Issue Type: Bug
          Components: Query Processor
    Affects Versions: 1.2.0
            Reporter: Lenni Kuff
            Priority: Critical


Hive does not treat floating point signed zeros as equal (-0.0 should equal 
0.0).  This is because Hive uses Double.compareTo(), which states:
"0.0d is considered by this method to be greater than -0.0d"

http://docs.oracle.com/javase/7/docs/api/java/lang/Double.html#compareTo(java.lang.Double)

The IEEE 754 floating point spec specifies that signed -0.0 and 0.0 should be 
treated as equal. From the Wikipedia article 
(https://en.wikipedia.org/wiki/Signed_zero#Comparisons):
bq. negative zero and positive zero should compare as equal with the usual 
(numerical) comparison operators


How to reproduce:
{code}

select 1 where 0.0=-0.0;
Returns no results.

select 1 where -0.0<0.0;
Returns 1
{code}



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