Chao Sun created HIVE-16328:
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Summary: HoS: more aggressive mapjoin optimization when
hive.spark.use.file.size.for.mapjoin is true
Key: HIVE-16328
URL: https://issues.apache.org/jira/browse/HIVE-16328
Project: Hive
Issue Type: Bug
Components: Logical Optimizer
Reporter: Chao Sun
Assignee: Chao Sun
In HIVE-15489, when {{hive.spark.use.file.size.for.mapjoin}} is set to true,
and if the JOIN op has any upstream RS operator, then we will stop converting
the JOIN op to MAPJOIN op.
However, this is overly conservative. A better solution is to treat the branch
that has upstream RS as the big table and check if all other branches are
map-only AND can fit in hash table size.
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