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https://issues.apache.org/jira/browse/HBASE-18122?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16027165#comment-16027165
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stack commented on HBASE-18122:
-------------------------------

Patch looks good [~yangzhe1991] Perhaps use MurmurHash instead of md5?  Good 
distribution, and cheaper than md5 and int32.

This bit I don't follow sir: "If a client has a scanner whose id is x, when the 
RS restart and the scanner id is also incremented to x or a little larger, 
there will be a scanner id collision.
So the scanner id should now be same during each time the RS restart. We can 
add the start timestamp as the highest several bits in scanner id uint64."

Why a collision? The scannerid is an increment on the rs starttime?

Thanks.

> Scanner id should include ServerName of region server
> -----------------------------------------------------
>
>                 Key: HBASE-18122
>                 URL: https://issues.apache.org/jira/browse/HBASE-18122
>             Project: HBase
>          Issue Type: Bug
>            Reporter: Phil Yang
>            Assignee: Phil Yang
>         Attachments: HBASE-18122.v01.patch
>
>
> Now the scanner id is a long number from 1 to max in a region server. Each 
> new scanner will have a scanner id.
> If a client has a scanner whose id is x, when the RS restart and the scanner 
> id is also incremented to x or a little larger, there will be a scanner id 
> collision.
> So the scanner id should now be same during each time the RS restart. We can 
> add the start timestamp as the highest several bits in scanner id uint64.
> And because HBASE-18121 is not easy to fix and there are many clients with 
> old version. We can also encode server host:port into the scanner id.
> So we can use ServerName.



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