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https://issues.apache.org/jira/browse/HIVE-7506?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14084160#comment-14084160
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Lars Francke commented on HIVE-7506:
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Just in case others don't know either: CBO = Cost Based Optimization, in the
future it'd be great if you could use the full form of acronyms at least once
in issues. Thank you!
As three very first review comments:
* Your latest patch doesn't apply cleanly on trunk, could you upload a new to
Review Board and link to the review here?
* Please set up your IDE to follow Hive coding conventions. You're using tabs
instead of spaces at least in your new files
* I just took a quick look but authorization integration seems to be missing
(e.g. no {{commandType}} entry in {{SemanticAnalyzerFactory}} but again I
haven't looked in detail yet because it doesn't apply correctly and I don't
fully understand the Auth code so I might be wrong :) )
This needs to be documented in multiple places if committed. These are the ones
I found so far:
* https://cwiki.apache.org/confluence/display/Hive/LanguageManual+Authorization
* https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL
* https://cwiki.apache.org/confluence/display/Hive/StatsDev
> 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.patch
>
> 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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