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https://issues.apache.org/jira/browse/HIVE-1918?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12997296#comment-12997296
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Krishna Kumar commented on HIVE-1918:
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There are a few reasons why I took this approach
- The decision on compatibility (forward/backward) checks as in
EximUtil.checkCompatibility needs to taken consciously. That is, automatically
breaking backward compatibility is not an option here I think.
- What needs to be serialized/deserialized is also requires a human decision.
For instance, even now, authorization details are not transferred by an
export/import.
- The serialization/deserialization methods are also used by howl codebase
outside of a hive context. It will be good to have this code only loosely
coupled to the metastore code.
> Add export/import facilities to the hive system
> -----------------------------------------------
>
> Key: HIVE-1918
> URL: https://issues.apache.org/jira/browse/HIVE-1918
> Project: Hive
> Issue Type: New Feature
> Components: Query Processor
> Reporter: Krishna Kumar
> Assignee: Krishna Kumar
> Attachments: HIVE-1918.patch.1.txt, HIVE-1918.patch.2.txt,
> HIVE-1918.patch.3.txt, HIVE-1918.patch.4.txt, HIVE-1918.patch.txt,
> hive-metastore-er.pdf
>
>
> This is an enhancement request to add export/import features to hive.
> With this language extension, the user can export the data of the table -
> which may be located in different hdfs locations in case of a partitioned
> table - as well as the metadata of the table into a specified output
> location. This output location can then be moved over to another different
> hadoop/hive instance and imported there.
> This should work independent of the source and target metastore dbms used;
> for instance, between derby and mysql.
> For partitioned tables, the ability to export/import a subset of the
> partition must be supported.
> Howl will add more features on top of this: The ability to create/use the
> exported data even in the absence of hive, using MR or Pig. Please see
> http://wiki.apache.org/pig/Howl/HowlImportExport for these details.
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