Shant Hovsepian has uploaded this change for review. ( http://gerrit.cloudera.org:8080/16349
Change subject: IMPALA-7310: Partial fix for NDV cardinality with NULLs. ...................................................................... IMPALA-7310: Partial fix for NDV cardinality with NULLs. This fix just handles the case where a column's cardinality is zero however it's nullable and we have null stats to indicate there are null values, therefore we adjust the cardinality from 0 to 1. The cardinality of zero was especially problematic when calculating cardinalities for multiple predicates with multiplication. The 0 would propagate up the plan tree and result in poor plan choices such as always using broadcast joins where shuffle would've been more optimal. Testing: * 26 Node TPC-DS 30TB run had better plans for Q4 and Q11 - Q4 172s -> 80s - Q11 103s -> 77s Change-Id: Iec967053b4991f8c67cde62adf003cbd3f429032 --- M fe/src/main/java/org/apache/impala/analysis/SlotRef.java M fe/src/test/java/org/apache/impala/analysis/ExprNdvTest.java M testdata/workloads/functional-planner/queries/PlannerTest/tpcds/tpcds-q04.test M testdata/workloads/functional-planner/queries/PlannerTest/tpcds/tpcds-q11.test 4 files changed, 751 insertions(+), 731 deletions(-) git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/49/16349/1 -- 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: newchange Gerrit-Change-Id: Iec967053b4991f8c67cde62adf003cbd3f429032 Gerrit-Change-Number: 16349 Gerrit-PatchSet: 1 Gerrit-Owner: Shant Hovsepian <sh...@cloudera.com>