[jira] [Commented] (HBASE-21885) Cancel remote procedure call if the remote procedure is succeeded

["Duo Zhang (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-21885?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16766735#comment-16766735 ] 

Duo Zhang commented on HBASE-21885:
-----------------------------------

[~sershe] [~stack] FYI.

> Cancel remote procedure call if the remote procedure is succeeded
> -----------------------------------------------------------------
>
>                 Key: HBASE-21885
>                 URL: https://issues.apache.org/jira/browse/HBASE-21885
>             Project: HBase
>          Issue Type: Improvement
>          Components: proc-v2
>            Reporter: Duo Zhang
>            Priority: Major
>
> I used to think it could rarely rarely happen that a region server can report back to master but master can not get the response from region server, only if there are strange network errors. But when implementing HBASE-21875, I found a way to reproduce the problem without any strange network issues.
> First time, we send the request to region server, and it accept the request, but before returning, there is a network error cause the connection to be broken, so master  will try to send the request to the region server again. But then the region server gets too busy, and always returns CallQueueTooBigException, then the master will retry forever, even if the region has already been opened on the region server.
> And this is not only waste more resources, as later we may close the region on the region server, and if the region server is back, we will receive an open region requst and a close region request at the same time. Not sure if this will cause any problems but at least, we haven't thought this condition yet.



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