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From "Ian Robertson (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HIVE-5839) BytesRefArrayWritable compareTo violates contract
Date Sun, 17 Nov 2013 19:23:21 GMT

     [ https://issues.apache.org/jira/browse/HIVE-5839?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Ian Robertson updated HIVE-5839:
--------------------------------

    Description: 
BytesRefArrayWritable's compareTo violates the compareTo contract from java.lang.Object. Specifically:

    The implementor must ensure sgn(x.compareTo( y )) == -sgn(y.compareTo( x )) for all x
and y.

The compareTo implementation on BytesRefArrayWritable does a proper comparison of the sizes
of the two instances. However, if the sizes are the same, it proceeds to do a check if both
array's have the same constant. If not, it returns 1. This means that if x and y are two BytesRefArrayWritable
instances with the same size, but different contents, then x.compareTo( y ) == 1 and y.compareTo(
x ) == 1.

Additionally, the comparison of contents is order agnostic. This seems wrong, since order
of entries should matter. It is also very inefficient, running at O(n^2), where n is the number
of entries.

  was:
BytesRefArrayWritable's compareTo violates the compareTo contract from java.lang.Object. Specifically:

    The implementor must ensure sgn(x.compareTo(y)) == -sgn(y.compareTo(x)) for all x and
y.

The compareTo implementation on BytesRefArrayWritable does a proper comparison of the sizes
of the two instances. However, if the sizes are the same, it proceeds to do a check if both
array's have the same constant. If not, it returns 1. This means that if x and y are two BytesRefArrayWritable
instances with the same size, but different contents, then x.compareTo(y) == 1 and y.compareTo(x)
== 1.

Additionally, the comparison of contents is order agnostic. This seems wrong, since order
of entries should matter. It is also very inefficient, running at O(n^2), where n is the number
of entries.


> BytesRefArrayWritable compareTo violates contract
> -------------------------------------------------
>
>                 Key: HIVE-5839
>                 URL: https://issues.apache.org/jira/browse/HIVE-5839
>             Project: Hive
>          Issue Type: Bug
>          Components: Serializers/Deserializers
>    Affects Versions: 0.11.0
>            Reporter: Ian Robertson
>
> BytesRefArrayWritable's compareTo violates the compareTo contract from java.lang.Object.
Specifically:
>     The implementor must ensure sgn(x.compareTo( y )) == -sgn(y.compareTo( x )) for all
x and y.
> The compareTo implementation on BytesRefArrayWritable does a proper comparison of the
sizes of the two instances. However, if the sizes are the same, it proceeds to do a check
if both array's have the same constant. If not, it returns 1. This means that if x and y are
two BytesRefArrayWritable instances with the same size, but different contents, then x.compareTo(
y ) == 1 and y.compareTo( x ) == 1.
> Additionally, the comparison of contents is order agnostic. This seems wrong, since order
of entries should matter. It is also very inefficient, running at O(n^2), where n is the number
of entries.



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