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https://issues.apache.org/jira/browse/HIVE-4331?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13750598#comment-13750598
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Francis Liu commented on HIVE-4331:
-----------------------------------

{quote}
No HCat and Hive dont treat OFs in same way. This difference of OF handling is 
a reason why HCatOF couldn't be used from Hive, another being HCat uses 
mapreduce api while Hive uses mapred api. If we can make Hive use HCatOF that 
will be a win, but thats yet another topic.
{quote}
Currently they don't mainly because of HOF but they behave in almost the same 
way else this whole interoperability story is broken. With this patch they'll 
at least be closer when it comes to dealing with OFs that don't use HOF. 
Instead of having to mirror that behavior.

Actually AFAIK only the HCatOF wrapper classes uses mapreduce and the 
underlying stuff deals with mapred which we did as part of the 
StorageDriver->SerDe migration. So it'd be relatively easy to support a mapred 
version of HCatOF.
                
> Integrated StorageHandler for Hive and HCat using the HiveStorageHandler
> ------------------------------------------------------------------------
>
>                 Key: HIVE-4331
>                 URL: https://issues.apache.org/jira/browse/HIVE-4331
>             Project: Hive
>          Issue Type: Task
>          Components: HCatalog
>    Affects Versions: 0.11.0, 0.12.0
>            Reporter: Ashutosh Chauhan
>            Assignee: Viraj Bhat
>         Attachments: HIVE4331_07-17.patch, StorageHandlerDesign_HIVE4331.pdf
>
>
> 1) Deprecate the HCatHBaseStorageHandler and "RevisionManager" from HCatalog. 
> These will now continue to function but internally they will use the 
> "DefaultStorageHandler" from Hive. They will be removed in future release of 
> Hive.
> 2) Design a HivePassThroughFormat so that any new StorageHandler in Hive will 
> bypass the HiveOutputFormat. We will use this class in Hive's 
> "HBaseStorageHandler" instead of the "HiveHBaseTableOutputFormat".
> 3) Write new unit tests in the HCat's "storagehandler" so that systems such 
> as Pig and Map Reduce can use the Hive's "HBaseStorageHandler" instead of the 
> "HCatHBaseStorageHandler".
> 4) Make sure all the old and new unit tests pass without backward 
> compatibility (except known issues as described in the Design Document).
> 5) Replace all instances of the HCat source code, which point to 
> "HCatStorageHandler" to use the"HiveStorageHandler" including the 
> "FosterStorageHandler".
> I have attached the design document for the same and will attach a patch to 
> this Jira.

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