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https://issues.apache.org/jira/browse/HIVE-7506?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14080125#comment-14080125
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Gunther Hagleitner commented on HIVE-7506:
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[~damien.carol] I think the use for this is different that analyze. The ability
to update certain stats without scanning any data or without "hacking the
backend db" is useful in a number of cases. It helps (esp for CBO work) to set
up unit tests quickly and verify both cbo and the stats subsystem. It also
helps when experimenting with the system if you're just trying out hive/hadoop
on a small cluster. Finally it gives you a quick and clean way to fix things
when something went wrong wrt stats in your environment.
> MetadataUpdater: provide a mechanism to edit the statistics of a column in a
> table (or a partition of a table)
> --------------------------------------------------------------------------------------------------------------
>
> Key: HIVE-7506
> URL: https://issues.apache.org/jira/browse/HIVE-7506
> Project: Hive
> Issue Type: New Feature
> Components: Database/Schema
> Reporter: pengcheng xiong
> Assignee: pengcheng xiong
> Priority: Minor
> Original Estimate: 252h
> Remaining Estimate: 252h
>
> Two motivations:
> (1) CBO depends heavily on the statistics of a column in a table (or a
> partition of a table). If we would like to test whether CBO chooses the best
> plan under different statistics, it would be time consuming if we load the
> whole table and create the statistics from ground up.
> (2) As database runs, the statistics of a column in a table (or a partition
> of a table) may change. We need a way or a mechanism to synchronize.
> We propose the following command to achieve that:
> ALTER TABLE table_name PARTITION partition_spec [COLUMN col_name] UPDATE
> STATISTICS col_statistics [COMMENT col_comment]
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