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https://issues.apache.org/jira/browse/HBASE-5877?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Zhihong Yu updated HBASE-5877:
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    Comment: was deleted

(was: @N:
I think the following validation in real cluster would illustrate the benefit 
of this feature:
For given table, select a region server and note the row key ranges hosted by 
the region server. Direct client load to this server.
Kill the server at time T.

Difference in client response to region migration around time T with and 
without the patch would be interesting.)
    
> When a query fails because the region has moved, let the regionserver return 
> the new address to the client
> ----------------------------------------------------------------------------------------------------------
>
>                 Key: HBASE-5877
>                 URL: https://issues.apache.org/jira/browse/HBASE-5877
>             Project: HBase
>          Issue Type: Improvement
>          Components: client, master, regionserver
>    Affects Versions: 0.96.0
>            Reporter: nkeywal
>            Assignee: nkeywal
>            Priority: Minor
>             Fix For: 0.96.0
>
>         Attachments: 5877.v1.patch
>
>
> This is mainly useful when we do a rolling restart. This will decrease the 
> load on the master and the network load.
> Note that a region is not immediately opened after a close. So:
> - it seems preferable to wait before retrying on the other server. An 
> optimisation would be to have an heuristic depending on when the region was 
> closed.
> - during a rolling restart, the server moves the regions then stops. So we 
> may have failures when the server is stopped, and this patch won't help.
> The implementation in the first patch does:
> - on the region move, there is an added parameter on the regionserver#close 
> to say where we are sending the region
> - the regionserver keeps a list of what was moved. Each entry is kept 100 
> seconds.
> - the regionserver sends a specific exception when it receives a query on a 
> moved region. This exception contains the new address.
> - the client analyses the exeptions and update its cache accordingly...

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