Mostafa Mokhtar created HIVE-9392:
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Summary: Hive : JoinStatsRule overwrites the column statistics in
HashMap because column names have duplicate fqColumnName
Key: HIVE-9392
URL: https://issues.apache.org/jira/browse/HIVE-9392
Project: Hive
Issue Type: Bug
Components: Physical Optimizer
Affects Versions: 0.14.0
Reporter: Mostafa Mokhtar
Assignee: Prasanth Jayachandran
Priority: Critical
Fix For: 0.15.0
In JoinStatsRule.process the join column statistics are stored in HashMap
joinedColStats, the key used which is the ColStatistics.fqColName is duplicated
between join column in the same vertex, as a result distinctVals ends up having
duplicated values which negatively affects the join cardinality estimation.
The duplicate keys are usually named KEY.reducesinkkey0.
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