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https://issues.apache.org/jira/browse/HBASE-10502?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13898138#comment-13898138
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Liyin Tang commented on HBASE-10502:
------------------------------------

In addition, the API of HBASE-10502 seems to more flexible (to me). Because if 
there is a single scan request, spanning multiple region boundaries, then hbase 
client is always able to split this scan request into multiple region-local 
scan requests, and then submit to HBASE-10502 for parallel execution.


> [89-fb] ParallelScanner: a client utility to perform multiple scan requests 
> in parallel.
> ----------------------------------------------------------------------------------------
>
>                 Key: HBASE-10502
>                 URL: https://issues.apache.org/jira/browse/HBASE-10502
>             Project: HBase
>          Issue Type: New Feature
>            Reporter: Liyin Tang
>             Fix For: 0.89-fb
>
>
> ParallelScanner is a utility class for the HBase client to perform multiple 
> scan requests in parallel. It requires all the scan requests having the same 
> caching size for the simplicity purpose. 
>  
> This class provides 3 very basic functionalities: 
> * The initialize function will Initialize all the ResultScanners by calling 
> {@link HTable#getScanner(Scan)} in parallel for each scan request.
> * The next function will call the corresponding {@link ResultScanner#next(int 
> numRows)} from each scan request in parallel, and then return all the results 
> together as a list.  Also, if result list is empty, it indicates there is no 
> data left for all the scanners and the user can call {@link #close()} 
> afterwards.
> * The close function will close all the scanners and shutdown the thread pool.



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