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Posted to issues@hive.apache.org by "ASF GitHub Bot (Jira)" <ji...@apache.org> on 2020/09/28 13:47:00 UTC
[jira] [Work logged] (HIVE-24203) Implement stats annotation rule
for the LateralViewJoinOperator
[ https://issues.apache.org/jira/browse/HIVE-24203?focusedWorklogId=491983&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-491983 ]
ASF GitHub Bot logged work on HIVE-24203:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 28/Sep/20 13:46
Start Date: 28/Sep/20 13:46
Worklog Time Spent: 10m
Work Description: okumin opened a new pull request #1531:
URL: https://github.com/apache/hive/pull/1531
### What changes were proposed in this pull request?
Estimate statistics of LATERAL VIEW correctly.
StatsRulesProcFactory doesn't have any rules to handle a JOIN by LATERAL VIEW.
This can cause an underestimation in case that UDTF in LATERAL VIEW generates multiple rows.
### Why are the changes needed?
Significant underestimation can happen when LATERAL VIEW increases the number of records a lot and the source table has large.
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
Added one test case.
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Issue Time Tracking
-------------------
Worklog Id: (was: 491983)
Remaining Estimate: 0h
Time Spent: 10m
> Implement stats annotation rule for the LateralViewJoinOperator
> ---------------------------------------------------------------
>
> Key: HIVE-24203
> URL: https://issues.apache.org/jira/browse/HIVE-24203
> Project: Hive
> Issue Type: Improvement
> Components: Physical Optimizer
> Affects Versions: 4.0.0, 3.1.2, 2.3.7
> Reporter: okumin
> Assignee: okumin
> Priority: Major
> Time Spent: 10m
> Remaining Estimate: 0h
>
> StatsRulesProcFactory doesn't have any rules to handle a JOIN by LATERAL VIEW.
> This can cause an underestimation in case that UDTF in LATERAL VIEW generates multiple rows.
> HIVE-20262 has already added the rule for UDTF.
> This issue would add the rule for LateralViewJoinOperator.
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