pengcheng xiong created HIVE-7654:
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Summary: 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
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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