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https://issues.apache.org/jira/browse/HIVE-28532?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Ramesh Kumar Thangarajan updated HIVE-28532:
--------------------------------------------
Description:
Map Join Reuse cache allows to share hashtables for different join types.
For example lets take Outer join and Inner join. We cannot reuse a hash table
for a non-outer join vs outer join. Because outer join cannot accept the hash
table kind other than HASHMAP, whereas there are other types like HASHSET and
HASH_MULTISET.
{code:java}
Caused by: java.lang.ClassCastException: class
org.apache.hadoop.hive.ql.exec.vector.mapjoin.fast.VectorMapJoinFastStringHashMultiSetContainer
cannot be cast to class
org.apache.hadoop.hive.ql.exec.vector.mapjoin.hashtable.VectorMapJoinHashMap
{code}
was:
Map Join Reuse cache allows to share hashtables for Outer join and Inner join.
But we cannot reuse a hash table for a non-outer join vs outer join. Because
outer join cannot accept the hash table kind other than HASHMAP, whereas there
are other types like HASHSET and HASH_MULTISET.
{code}
Caused by: java.lang.ClassCastException: class
org.apache.hadoop.hive.ql.exec.vector.mapjoin.fast.VectorMapJoinFastStringHashMultiSetContainer
cannot be cast to class
org.apache.hadoop.hive.ql.exec.vector.mapjoin.hashtable.VectorMapJoinHashMap
{code}
> Map Join Reuse cache allows to share hashtables for different join types
> ------------------------------------------------------------------------
>
> Key: HIVE-28532
> URL: https://issues.apache.org/jira/browse/HIVE-28532
> Project: Hive
> Issue Type: Bug
> Security Level: Public(Viewable by anyone)
> Components: Logical Optimizer
> Affects Versions: 4.0.0
> Reporter: Ramesh Kumar Thangarajan
> Assignee: Ramesh Kumar Thangarajan
> Priority: Major
>
> Map Join Reuse cache allows to share hashtables for different join types.
> For example lets take Outer join and Inner join. We cannot reuse a hash table
> for a non-outer join vs outer join. Because outer join cannot accept the hash
> table kind other than HASHMAP, whereas there are other types like HASHSET and
> HASH_MULTISET.
> {code:java}
> Caused by: java.lang.ClassCastException: class
> org.apache.hadoop.hive.ql.exec.vector.mapjoin.fast.VectorMapJoinFastStringHashMultiSetContainer
> cannot be cast to class
> org.apache.hadoop.hive.ql.exec.vector.mapjoin.hashtable.VectorMapJoinHashMap
> {code}
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