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From "Taras Bobrovytsky (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-6388: Fix the Union node number of hosts estimation
Date Fri, 12 Jan 2018 21:29:32 GMT
Taras Bobrovytsky has uploaded a new patch set (#3). ( http://gerrit.cloudera.org:8080/9017
)

Change subject: IMPALA-6388: Fix the Union node number of hosts estimation
......................................................................

IMPALA-6388: Fix the Union node number of hosts estimation

Before this patch, we would estimate the number of hosts for the union
node by looking only at the first union operand. This is obviously
incorrect and lead us to underestimate the value.

We fix the problem by setting the estimate to be the maximum of its
children.

Testing:
- Added a planner test that reproduces the issue

Change-Id: I51e1ecca8dbc84b2b5a72708667b2799d00279f0
---
M fe/src/main/java/org/apache/impala/planner/UnionNode.java
M testdata/workloads/functional-planner/queries/PlannerTest/union.test
2 files changed, 89 insertions(+), 0 deletions(-)


  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/17/9017/3
-- 
To view, visit http://gerrit.cloudera.org:8080/9017
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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I51e1ecca8dbc84b2b5a72708667b2799d00279f0
Gerrit-Change-Number: 9017
Gerrit-PatchSet: 3
Gerrit-Owner: Taras Bobrovytsky <tbobrovytsky@cloudera.com>
Gerrit-Reviewer: Alex Behm <alex.behm@cloudera.com>
Gerrit-Reviewer: Taras Bobrovytsky <tbobrovytsky@cloudera.com>

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