[jira] [Commented] (HIVE-7072) HCatLoader only loads first region of hbase table

["Sushanth Sowmyan (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-7072?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14011834#comment-14011834 ] 

Sushanth Sowmyan commented on HIVE-7072:
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Note for future readers: pig actually has two parameters : pig.splitCombination and pig.noSplitCombination, which are inverses of each other. The workaround for this issue for people is to set "pig.splitCombination" to "false" inside the pig script before invoking HCatLoader. However, it does not work for HCatLoader to set that parameter inside the setLocation, for that is too late (that parameter seems to be evaluated prior to hcat being loaded, in order to set its opposite twin) - instead, it should set the "pig.noSplitCombination" to true, and then pig is able to pick that up from within the job.

> HCatLoader only loads first region of hbase table
> -------------------------------------------------
>
>                 Key: HIVE-7072
>                 URL: https://issues.apache.org/jira/browse/HIVE-7072
>             Project: Hive
>          Issue Type: Bug
>    Affects Versions: 0.14.0
>            Reporter: Sushanth Sowmyan
>            Assignee: Sushanth Sowmyan
>
> Pig needs a config parameter 'pig.noSplitCombination' set to 'true' for it to be able to read HBaseStorageHandler-based tables.
> This is done in the HBaseLoader at getSplits time, but HCatLoader does not do so, which results in only a partial data load.
> Thus, we need one more special case definition in HCat, that sets this parameter in the job properties if we detect that we're loading a HBaseStorageHandler based table. The primary issue is one of where this code should go, since it doesn't belong in pig (pig does not know what loader behaviour should be, and this parameter is its interface to a loader), and doesn't belong in the HBaseStorageHandler either, since that's implementing a HiveStorageHandler and is connecting up the two. Thus, this should belong to HCatLoader. Setting this parameter across the board results in poor performance for HCatLoader, so it must only be set when using with HBase.
> Thus, it belongs in the SpecialCases definition as that was created specifically for these kinds of odd cases, and can be called from within HCatLoader.



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