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Posted to issues@kylin.apache.org by "Feng Zhu (Jira)" <ji...@apache.org> on 2021/01/27 11:01:00 UTC
[jira] [Created] (KYLIN-4888) Performance optimization of union
query with spark engine
Feng Zhu created KYLIN-4888:
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Summary: Performance optimization of union query with spark engine
Key: KYLIN-4888
URL: https://issues.apache.org/jira/browse/KYLIN-4888
Project: Kylin
Issue Type: Improvement
Components: Spark Engine
Affects Versions: v4.0.0-alpha
Reporter: Feng Zhu
Fix For: v4.0.0-beta
when using union query with spark engine, UnionPlan transforms OLAPUnionRel to spark
DataFrame, when OLAPUnionRel.all = false, distinct transformation of spark will be used, but
but it used in a loop which traversing DataFrame collection so that there are so many stages in spark dag. Actuall, distinct transformation should be used only once at last.
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