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From "Ashutosh Chauhan (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HIVE-7506) MetadataUpdater: provide a mechanism to edit the statistics of a column in a table (or a partition of a table)
Date Fri, 08 Aug 2014 18:25:13 GMT

     [ https://issues.apache.org/jira/browse/HIVE-7506?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Ashutosh Chauhan updated HIVE-7506:
-----------------------------------

    Status: Open  (was: Patch Available)

Left comments on RB. Two major items:
* Add .q tests.
* Add new HiveOperation enum corresponding to new token type.

> 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: Statistics
>            Reporter: pengcheng xiong
>            Assignee: pengcheng xiong
>            Priority: Minor
>         Attachments: HIVE-7506.1.patch, HIVE-7506.3.patch, HIVE-7506.4.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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