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From "Duo Zhang (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-16838) Implement scan
Date Tue, 25 Oct 2016 03:38:58 GMT

    [ https://issues.apache.org/jira/browse/HBASE-16838?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15604061#comment-15604061
] 

Duo Zhang commented on HBASE-16838:
-----------------------------------

{quote}
You mean a whole region's worth of results or you mean the batch?
{quote}

I mean the whole result of a scan, not the data of the whole region...

And the observer API is borrowed from grpc, but It is not suitable for some scenarios, for
example, MR. And it calls the onNext method directly in the event loop thread so the method
can not be blocked. And if users use another thread to process the result and return immediately
from the onNext method, then it may cause OOM as we do not have flow control. A flow controled
scan could be built on top of the observe API, but to be honest, I do not have a good API
to expose the 'flow controlled' scan out yet...

Thanks.

> Implement scan
> --------------
>
>                 Key: HBASE-16838
>                 URL: https://issues.apache.org/jira/browse/HBASE-16838
>             Project: HBase
>          Issue Type: Sub-task
>    Affects Versions: 2.0.0
>            Reporter: Duo Zhang
>            Assignee: Duo Zhang
>             Fix For: 2.0.0
>
>         Attachments: HBASE-16838.patch
>
>




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