[
https://issues.apache.org/jira/browse/HIVE-7506?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14074928#comment-14074928
]
Damien Carol commented on HIVE-7506:
------------------------------------
If the metastore use an RDBMS for backend, you can hack statistics in this.
Anyway, the command ANALYZE answer your (2).
> 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: Critical
> 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]
--
This message was sent by Atlassian JIRA
(v6.2#6252)
