Shant Hovsepian has posted comments on this change. ( http://gerrit.cloudera.org:8080/16349 )
Change subject: IMPALA-7310: Partial fix for NDV cardinality with NULLs. ...................................................................... Patch Set 1: This is a bit of a lazy fix, handling only the case where ndv is 0 but there are null stats. I tried updating the cardinality with null info in all cases created some big plan changes across the board, to do this change justice we'd need to fix cardinality and selectivity calculation to factor out the number of null values in cases where a predicate is null filtering. The IS NOT NULL predicate does this explicitly but we not other predicates. I welcome people's input on prioritizing the general fix, just makes for LOTS of plan diffs to review. If we're okay with just this partial fix I'll make a separate JIRA for it. Also still expecting more test changes, having trouble with loading data with Tez and memory consumption as well as some more Hbase issues. -- To view, visit http://gerrit.cloudera.org:8080/16349 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Iec967053b4991f8c67cde62adf003cbd3f429032 Gerrit-Change-Number: 16349 Gerrit-PatchSet: 1 Gerrit-Owner: Shant Hovsepian <[email protected]> Gerrit-Reviewer: Aman Sinha <[email protected]> Gerrit-Reviewer: David Rorke <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Qifan Chen <[email protected]> Gerrit-Reviewer: Shant Hovsepian <[email protected]> Gerrit-Reviewer: Tim Armstrong <[email protected]> Gerrit-Comment-Date: Fri, 21 Aug 2020 06:08:27 +0000 Gerrit-HasComments: No
