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https://issues.apache.org/jira/browse/HIVE-72?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Carl Steinbach updated HIVE-72:
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Fix Version/s: 0.3.0
(was: 0.6.0)
Component/s: Query Processor
> wrong results if partition pruning not strict and no mep-reduce job needed
> --------------------------------------------------------------------------
>
> Key: HIVE-72
> URL: https://issues.apache.org/jira/browse/HIVE-72
> Project: Hadoop Hive
> Issue Type: Bug
> Components: Query Processor
> Reporter: Namit Jain
> Assignee: Namit Jain
> Fix For: 0.3.0
>
> Attachments: patch1.mapred.txt
>
>
> Suppose T is a partitioned table on ds, where ds is a string column, the
> following queries:
> SELECT a.* FROM T a WHERE a.ds=2008-09-08 LIMIT 1;
> SELECT a.* FROM T a WHERE a.ds=2008-11-10 LIMIT 1;
> return the first row from the first partition.
> This is because of the typecast to double.
> for a.ds=2008-01-01 or anything (a.ds=1),
> evaluate (Double, Double) is invoked at partition pruning.
> Since '2008-11-01' is not a valid double, it is converted to a null, and
> therefore the result of pruning returns null (unknown) - not FALSE.
> All unknowns are also accepted, therefore all partitions are accepted which
> explains this behavior.
> filter is not invoked since it is a select * query, so map-reduce job is
> started.
> We just turn off this optimization if pruning indicates that there can be
> unknown partitions.
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