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https://issues.apache.org/jira/browse/HIVE-11174?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Lenni Kuff updated HIVE-11174:
------------------------------
Description:
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
(http://docs.oracle.com/javase/7/docs/api/java/lang/Double.html#compareTo(java.lang.Double):
bq. 0.0d is considered by this method to be greater than -0.0d
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
Java's compareTo method is implemented to allow for ordering of object
instances (in a hash table or similar), but Hive should abide by the IEEE spec.
How to reproduce:
{code}
select 1 where 0.0=-0.0;
Returns no results.
select 1 where -0.0<0.0;
Returns 1
{code}
was:
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}
> 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
> (http://docs.oracle.com/javase/7/docs/api/java/lang/Double.html#compareTo(java.lang.Double):
> bq. 0.0d is considered by this method to be greater than -0.0d
> 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
> Java's compareTo method is implemented to allow for ordering of object
> instances (in a hash table or similar), but Hive should abide by the IEEE
> spec.
> 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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