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https://issues.apache.org/jira/browse/HIVE-22238?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16962191#comment-16962191
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Hive QA commented on HIVE-22238:
--------------------------------
Here are the results of testing the latest attachment:
https://issues.apache.org/jira/secure/attachment/12984247/HIVE-22238.05.patch
{color:red}ERROR:{color} -1 due to build exiting with an error
Test results:
https://builds.apache.org/job/PreCommit-HIVE-Build/19193/testReport
Console output: https://builds.apache.org/job/PreCommit-HIVE-Build/19193/console
Test logs: http://104.198.109.242/logs/PreCommit-HIVE-Build-19193/
Messages:
{noformat}
Executing org.apache.hive.ptest.execution.TestCheckPhase
Tests exited with: Exception: Patch URL
https://issues.apache.org/jira/secure/attachment/12984247/HIVE-22238.05.patch
was found in seen patch url's cache and a test was probably run already on it.
Aborting...
{noformat}
This message is automatically generated.
ATTACHMENT ID: 12984247 - PreCommit-HIVE-Build
> PK/FK selectivity estimation underscales estimations
> ----------------------------------------------------
>
> Key: HIVE-22238
> URL: https://issues.apache.org/jira/browse/HIVE-22238
> Project: Hive
> Issue Type: Bug
> Components: Statistics
> Reporter: Zoltan Haindrich
> Assignee: Zoltan Haindrich
> Priority: Major
> Labels: pull-request-available
> Attachments: HIVE-22238.01.patch, HIVE-22238.02.patch,
> HIVE-22238.03.patch, HIVE-22238.04.patch, HIVE-22238.05.patch,
> HIVE-22238.05.patch
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> at [this
> point|https://github.com/apache/hive/blob/5098d155a1e6a164253f5fa98755273bc34085df/ql/src/java/org/apache/hadoop/hive/ql/optimizer/stats/annotation/StatsRulesProcFactory.java#L2182]
> the parent operators rownum is scaled according to pkfkselectivity
> however [pkfkselectivity is
> computed|https://github.com/apache/hive/blob/5098d155a1e6a164253f5fa98755273bc34085df/ql/src/java/org/apache/hadoop/hive/ql/optimizer/stats/annotation/StatsRulesProcFactory.java#L2157]
> on a whole subtree.
> Scaling it by that amount will count in estimation already used when
> parentstats was calculated...so depending on the number of upstream joins -
> this may lead to severe underestimations
> what happened was:
> * optimization was able to push the filter to the other side of the join
> * as a result the incoming data was already filtered
> * scaling down by the PK selectiviy - was actually already there...but a new
> "scaling" happened
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