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Phabricator commented on HIVE-948: ---------------------------------- njain has commented on the revision "HIVE-948 [jira] more query plan optimization rules". INLINE COMMENTS ql/src/java/org/apache/hadoop/hive/ql/optimizer/Optimizer.java:98 I missed this patch - Had some questions. ql/src/java/org/apache/hadoop/hive/ql/optimizer/NonBlockingOpDeDupProc.java:93 Have you missed some files - this function removeChild... does not seem to exist ql/src/java/org/apache/hadoop/hive/ql/optimizer/NonBlockingOpDeDupProc.java:80 You are checking for: SEL-SEL(compute), the comment looks wrong REVISION DETAIL https://reviews.facebook.net/D8463 To: JIRA, ashutoshc, navis Cc: njain > more query plan optimization rules > ----------------------------------- > > Key: HIVE-948 > URL: https://issues.apache.org/jira/browse/HIVE-948 > Project: Hive > Issue Type: Improvement > Reporter: Ning Zhang > Assignee: Navis > Attachments: HIVE-948.D8463.1.patch, HIVE-948.D8463.2.patch, > HIVE-948.D8463.3.patch, HIVE-948.D8463.3.patch, HIVE-948.D8463.4.patch, > HIVE-948.testresult_only.txt > > > Many query plans are not optimal in that they contain redundant operators. > Some examples are unnecessary select operators (select followed by select, > select output being the same as input etc.). Even though these operators are > not very expensive, they could account for around 10% of CPU time in some > simple queries. It seems they are low-hanging fruits that we should pick > first. > BTW, it seems these optimization rules should be added at the last stage of > the physical optimization phase since some redundant operators are added to > facilitate physical plan generation. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira