liuyao has posted comments on this change. ( http://gerrit.cloudera.org:8080/17637 )
Change subject: IMPALA-10766: Better selectivity for =,not distinct ...................................................................... Patch Set 6: (3 comments) http://gerrit.cloudera.org:8080/#/c/17637/5/fe/src/main/java/org/apache/impala/analysis/BinaryPredicate.java File fe/src/main/java/org/apache/impala/analysis/BinaryPredicate.java: http://gerrit.cloudera.org:8080/#/c/17637/5/fe/src/main/java/org/apache/impala/analysis/BinaryPredicate.java@250 PS5, Line 250: rChildIsNull > nit. Do we need to worry about left child is null here, or not since the le Considering this special situation, the selectivity will be more accurate. http://gerrit.cloudera.org:8080/#/c/17637/5/fe/src/main/java/org/apache/impala/analysis/BinaryPredicate.java@280 PS5, Line 280: // For =, !=, "is distinct from null" and "is not distinct from non-null", : // all null values are false. : selectivity_ *= (double) (numRows - numNulls) / numRows; > nit. may combine them into a single sentence: Done http://gerrit.cloudera.org:8080/#/c/17637/5/fe/src/main/java/org/apache/impala/analysis/BinaryPredicate.java@284 PS5, Line 284: stinct from null, only null values are > Another case here is "is distinct from not-null". Done -- To view, visit http://gerrit.cloudera.org:8080/17637 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Ib8ec62f2355a7036125cc0d261b790644b9f4b60 Gerrit-Change-Number: 17637 Gerrit-PatchSet: 6 Gerrit-Owner: liuyao <liu...@sensorsdata.cn> Gerrit-Reviewer: Aman Sinha <amsi...@cloudera.com> Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com> Gerrit-Reviewer: Qifan Chen <qc...@cloudera.com> Gerrit-Reviewer: Zoltan Borok-Nagy <borokna...@cloudera.com> Gerrit-Reviewer: liuyao <liu...@sensorsdata.cn> Gerrit-Comment-Date: Mon, 12 Jul 2021 08:40:21 +0000 Gerrit-HasComments: Yes
