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https://issues.apache.org/jira/browse/HIVE-1361?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Ning Zhang updated HIVE-1361:
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Attachment: HIVE-1361.patch
HIVE-1361.java_only.patch
Uploading a full version (HIVE-1361.patch) and a Java code only version
(HIVE-1361.java_only.patch).
This patch is based on Ahmed's previous patch and implements the following
feature:
1) automatically gather stats (number of rows currently) whenever an INSERT
OVERWRITE TABLE is issued. Each mapper/reducer push their partial stats to
either MySQL/Derby through JDBC or HBase. The INSERT OVERWRITE statement could
be anything include dynamic partition insert, multi-table inserts and inserting
to bucketized partitions. A StatsTask is responsible for aggregating partial
stats at the end of the query and update the metastore.
2) The stats of a table/partition can be exposed to the user by 'DESC
EXTENDED' to the table/partition. They are stored as the storage parameters
(numRows, nuFiles, numPartitions).
3) Introducing a new command 'ANALYZE TABLE [PARTITION (PARTITION SPEC)]
COMPUTE STATISTICS' to scan the table/partition and gather stats in a similar
fashion as INSERT OVERWRITE command except that the plan has only 1 MR job
consisting a TableScanOperator and a StatsTask. Partition spec could be full
partition spec or partial partition spec similar to what dynamic partition
insert uses. This allows the user to analyze a subset/all partitions of a
table. The resulting stats are stored in the same parameter in the meatstore.
Tested locally (unit tests) for JDBC:derby, hbase and on a cluster with
JDBC:MySQL.
Will run the full unit tests again.
> table/partition level statistics
> --------------------------------
>
> Key: HIVE-1361
> URL: https://issues.apache.org/jira/browse/HIVE-1361
> Project: Hadoop Hive
> Issue Type: Sub-task
> Affects Versions: 0.6.0
> Reporter: Ning Zhang
> Assignee: Ahmed M Aly
> Attachments: HIVE-1361.java_only.patch, HIVE-1361.patch, stats0.patch
>
>
> At the first step, we gather table-level stats for non-partitioned table and
> partition-level stats for partitioned table. Future work could extend the
> table level stats to partitioned table as well.
> There are 3 major milestones in this subtask:
> 1) extend the insert statement to gather table/partition level stats
> on-the-fly.
> 2) extend metastore API to support storing and retrieving stats for a
> particular table/partition.
> 3) add an ANALYZE TABLE [PARTITION] statement in Hive QL to gather stats for
> existing tables/partitions.
> The proposed stats are:
> Partition-level stats:
> - number of rows
> - total size in bytes
> - number of files
> - max, min, average row sizes
> - max, min, average file sizes
> Table-level stats in addition to partition level stats:
> - number of partitions
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