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https://issues.apache.org/jira/browse/HIVE-11531?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15053482#comment-15053482
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Sergey Shelukhin commented on HIVE-11531:
-----------------------------------------
It appears that union9 is broken since the patch has been committed. The stats
have gone negative for some queries. Can you double check?
[~prasanth_j] what do negative stats mean?
{noformat}
< Statistics: Num rows: -1 Data size: 5812 Basic stats: PARTIAL
Column stats: COMPLETE
< Statistics: Num rows: -1 Data size: 5812 Basic stats: PARTIAL
Column stats: COMPLETE
< Statistics: Num rows: -1 Data size: 5812 Basic stats: PARTIAL
Column stats: COMPLETE
< Statistics: Num rows: -1 Data size: 5812 Basic stats: PARTIAL
Column stats: COMPLETE
< Statistics: Num rows: -1 Data size: 5812 Basic stats: PARTIAL
Column stats: COMPLETE
< Statistics: Num rows: -1 Data size: 5812 Basic stats: PARTIAL
Column stats: COMPLETE
---
> Statistics: Num rows: 1500 Data size: 0 Basic stats:
> PARTIAL Column stats: COMPLETE
> Statistics: Num rows: 1500 Data size: 0 Basic stats:
> PARTIAL Column stats: COMPLETE
> Statistics: Num rows: 1500 Data size: 0 Basic stats:
> PARTIAL Column stats: COMPLETE
> Statistics: Num rows: 1500 Data size: 0 Basic stats: PARTIAL
> Column stats: COMPLETE
> Statistics: Num rows: 1500 Data size: 0 Basic stats: PARTIAL
> Column stats: COMPLETE
> Statistics: Num rows: 1500 Data size: 0 Basic stats: PARTIAL
> Column stats: COMPLETE
{noformat}
> Add mysql-style LIMIT support to Hive, or improve ROW_NUMBER performance-wise
> -----------------------------------------------------------------------------
>
> Key: HIVE-11531
> URL: https://issues.apache.org/jira/browse/HIVE-11531
> Project: Hive
> Issue Type: Improvement
> Components: CBO
> Reporter: Sergey Shelukhin
> Assignee: Hui Zheng
> Fix For: 2.1.0
>
> Attachments: HIVE-11531.02.patch, HIVE-11531.03.patch,
> HIVE-11531.04.patch, HIVE-11531.05.patch, HIVE-11531.06.patch,
> HIVE-11531.07.patch, HIVE-11531.WIP.1.patch, HIVE-11531.WIP.2.patch,
> HIVE-11531.patch
>
>
> For any UIs that involve pagination, it is useful to issue queries in the
> form SELECT ... LIMIT X,Y where X,Y are coordinates inside the result to be
> paginated (which can be extremely large by itself). At present, ROW_NUMBER
> can be used to achieve this effect, but optimizations for LIMIT such as TopN
> in ReduceSink do not apply to ROW_NUMBER. We can add first class support for
> "skip" to existing limit, or improve ROW_NUMBER for better performance
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