Hello Quanlong Huang, Csaba Ringhofer, Impala Public Jenkins,
I'd like you to reexamine a change. Please visit
http://gerrit.cloudera.org:8080/21516
to look at the new patch set (#2).
Change subject: IMPALA-13077: Fix selectivity estimation for SEMI JOIN
......................................................................
IMPALA-13077: Fix selectivity estimation for SEMI JOIN
JoinNode.getSemiJoinCardinality() will skip an equality expression if
either NDV or Cardinality of equality expression is unknown (-1). If NDV
is unknown, but Cardinality is known, getSemiJoinCardinality() should
assume NDV = Cardinality. On the other hand, assume NDV = 1 if that NDV
is being used as a divisor in the selectivity formula to prevent
underestimation.
Testing:
- Add test case where LEFT SEMI JOIN from subquery can reduce
cardinality estimate of leftmost ScanNode in the query plan.
- Pass core tests.
Change-Id: I9c799df535d764c3f87ededef1c48eaa103293a0
---
M fe/src/main/java/org/apache/impala/planner/JoinNode.java
M
testdata/workloads/functional-planner/queries/PlannerTest/runtime-filter-propagation.test
M
testdata/workloads/functional-planner/queries/PlannerTest/subquery-rewrite.test
3 files changed, 55 insertions(+), 10 deletions(-)
git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/16/21516/2
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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I9c799df535d764c3f87ededef1c48eaa103293a0
Gerrit-Change-Number: 21516
Gerrit-PatchSet: 2
Gerrit-Owner: Riza Suminto <[email protected]>
Gerrit-Reviewer: Csaba Ringhofer <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Quanlong Huang <[email protected]>
Gerrit-Reviewer: Riza Suminto <[email protected]>
