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https://issues.apache.org/jira/browse/HIVE-7506?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14085905#comment-14085905
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Lars Francke commented on HIVE-7506:
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Pengcheng, thanks for providing a new review and better patch.
I've looked at the latest review:
* The latest review is still not using spaces everywhere, there are also a lot
of unrelated whitespace changes. If you're using IntelliJ I'm happy to help
getting you set up
* Could you update the existing review (linked in this issue now) instead of
creating a new one. Again, if you need help let me know.
* Could you comment on the authorization part? I'm not too sure about this
myself.
* Having only taken a cursory look so far: Why did the fields in
MTableColumnStatistics etc. change from primitives to boxed objects (long ->
Long etc.)?
I'll do a full review once a clean patch is up.
> 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
> Attachments: HIVE-7506.1.patch, HIVE-7506.1.patch, HIVE-7506.3.patch,
> HIVE-7506.patch
>
> Original Estimate: 252h
> Remaining Estimate: 252h
>
> Two motivations:
> (1) Cost-based Optimizer (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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