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https://issues.apache.org/jira/browse/HIVE-7654?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14107145#comment-14107145
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Szehon Ho commented on HIVE-7654:
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Thanks for the detailed explanation.
> A method to extrapolate columnStats for partitions of a table
> -------------------------------------------------------------
>
> Key: HIVE-7654
> URL: https://issues.apache.org/jira/browse/HIVE-7654
> Project: Hive
> Issue Type: New Feature
> Reporter: pengcheng xiong
> Assignee: pengcheng xiong
> Priority: Minor
> Attachments: Extrapolate the Column Status.docx, HIVE-7654.0.patch,
> HIVE-7654.1.patch, HIVE-7654.4.patch, HIVE-7654.6.patch, HIVE-7654.7.patch,
> HIVE-7654.8.patch
>
>
> In a PARTITIONED table, there are many partitions. For example,
> create table if not exists loc_orc (
> state string,
> locid int,
> zip bigint
> ) partitioned by(year string) stored as orc;
> We assume there are 4 partitions, partition(year='2000'),
> partition(year='2001'), partition(year='2002') and partition(year='2003').
> We can use the following command to compute statistics for columns
> state,locid of partition(year='2001')
> analyze table loc_orc partition(year='2001') compute statistics for columns
> state,locid;
> We need to know the “aggregated” column status for the whole table loc_orc.
> However, we may not have the column status for some partitions, e.g.,
> partition(year='2002') and also we may not have the column status for some
> columns, e.g., zip bigint for partition(year='2001')
> We propose a method to extrapolate the missing column status for the
> partitions.
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