Paul Rogers has posted comments on this change. ( http://gerrit.cloudera.org:8080/11565 )
Change subject: IMPALA-7659: Populate NULL count while computing column stats ...................................................................... Patch Set 6: (1 comment) http://gerrit.cloudera.org:8080/#/c/11565/6/fe/src/main/java/org/apache/impala/analysis/ComputeStatsStmt.java File fe/src/main/java/org/apache/impala/analysis/ComputeStatsStmt.java: http://gerrit.cloudera.org:8080/#/c/11565/6/fe/src/main/java/org/apache/impala/analysis/ComputeStatsStmt.java@251 PS6, Line 251: " IS NULL THEN 1 ELSE NULL END)"); If we compute the null count, can we also solve the NDV=0 issue? Before saving the NDV, add one if the null count is greater than zero. This will ensure that the NDV count here matches the planner's expectation of NDV-including-nulls. -- To view, visit http://gerrit.cloudera.org:8080/11565 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Ic68f8b4c3756eb1980ce299a602a7d56db1e507a Gerrit-Change-Number: 11565 Gerrit-PatchSet: 6 Gerrit-Owner: Anonymous Coward <piotr.findei...@gmail.com> Gerrit-Reviewer: Anonymous Coward <piotr.findei...@gmail.com> Gerrit-Reviewer: Bharath Vissapragada <bhara...@cloudera.com> Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com> Gerrit-Reviewer: Paul Rogers <par0...@yahoo.com> Gerrit-Reviewer: Tim Armstrong <tarmstr...@cloudera.com> Gerrit-Reviewer: Vuk Ercegovac <vercego...@cloudera.com> Gerrit-Comment-Date: Sat, 01 Dec 2018 00:29:08 +0000 Gerrit-HasComments: Yes
