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From "Paul Yang (JIRA)" <j...@apache.org>
Subject [jira] Updated: (HIVE-1332) Archiving partitions
Date Mon, 07 Jun 2010 21:03:49 GMT

     [ https://issues.apache.org/jira/browse/HIVE-1332?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Paul Yang updated HIVE-1332:

    Status: Patch Available  (was: Open)

> Archiving partitions
> --------------------
>                 Key: HIVE-1332
>                 URL: https://issues.apache.org/jira/browse/HIVE-1332
>             Project: Hadoop Hive
>          Issue Type: New Feature
>          Components: Metastore
>    Affects Versions: 0.6.0
>            Reporter: Paul Yang
>            Assignee: Paul Yang
>         Attachments: HIVE-1332.1.patch, HIVE-1332.2.patch, HIVE-1332.3.patch, HIVE-1332.4.patch,
> Partitions and tables in Hive typically consist of many files on HDFS. An issue is that
as the number of files increase, there will be higher memory/load requirements on the namenode.
Partitions in bucketed tables are a particular problem because they consist of many files,
one for each of the buckets.
> One way to drastically reduce the number of files is to use hadoop archives:
> http://hadoop.apache.org/common/docs/current/hadoop_archives.html
> This feature would introduce an ALTER TABLE <table_name> ARCHIVE PARTITION <spec>
that would automatically put the files for the partition into a HAR file. We would also have
an UNARCHIVE option to convert the files in the partition back to the original files. Archived
partitions would be slower to access, but they would have the same functionality and decrease
the number of files drastically. Typically, only seldom accessed partitions would be archived.
> Hadoop archives are still somewhat new, so we'll only put in support for the latest released
major version (0.20). Here are some bug fixes:
> https://issues.apache.org/jira/browse/HADOOP-6591 (Important - could potentially cause
data loss without this fix)
> https://issues.apache.org/jira/browse/HADOOP-6645
> https://issues.apache.org/jira/browse/MAPREDUCE-1585

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