Gautam Kumar Parai created DRILL-4743:
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Summary: HashJoin's not fully parallelized in query plan
Key: DRILL-4743
URL: https://issues.apache.org/jira/browse/DRILL-4743
Project: Apache Drill
Issue Type: Bug
Affects Versions: 1.5.0
Reporter: Gautam Kumar Parai
Assignee: Gautam Kumar Parai
The underlying problem is filter selectivity under-estimate for a query with
complicated predicates e.g. deeply nested and/or predicates. This leads to
under parallelization of the major fragment doing the join.
To really resolve this problem we need table/column statistics to correctly
estimate the selectivity. However, in the absence of statistics OR even when
existing statistics are insufficient to get a correct estimate of selectivity
this will serve as a workaround.
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