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From "Karan Mehta (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-18042) Client Compatibility breaks between versions 1.2 and 1.3
Date Fri, 12 May 2017 18:07:04 GMT

    [ https://issues.apache.org/jira/browse/HBASE-18042?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16008497#comment-16008497

Karan Mehta commented on HBASE-18042:

A simple solution for this is to not close the scanner even if there are no more results in
region. I am not sure about other implications due to this though.
       addResults(builder, results, (PayloadCarryingRpcController) controller,
-      if (!moreResults || !moreResultsInRegion || closeScanner) {
+      if (!moreResults || closeScanner) {
         scannerClosed = true;
         closeScanner(region, scanner, scannerName, context);

> Client Compatibility breaks between versions 1.2 and 1.3
> --------------------------------------------------------
>                 Key: HBASE-18042
>                 URL: https://issues.apache.org/jira/browse/HBASE-18042
>             Project: HBase
>          Issue Type: Bug
>            Reporter: Karan Mehta
> OpenTSDB uses AsyncHBase as its client, rather than using the traditional HBase Client.
From version 1.2 to 1.3, the {{ClientProtos}} have been changed. Newer fields are added to
{{ScanResponse}} proto.
> For a typical Scan request in 1.2, would require caller to make an OpenScanner Request,
GetNextRows Request and a CloseScanner Request, based on {{more_rows}} boolean field in the
{{ScanResponse}} proto.
> However, from 1.3, new parameter {{more_results_in_region}} was added, which limits the
results per region. Therefore the client has to now manage sending all the requests for each
region. Further more, if the results are exhausted from a particular region, the {{ScanResponse}}
will set {{more_results_in_region}} to false, but {{more_results}} can still be true. Whenever
the former is set to false, the {{RegionScanner}} will also be closed. 
> OpenTSDB makes an OpenScanner Request and receives all its results in the first {{ScanResponse}}
itself, thus creating a condition as described in above paragraph. Since {{more_rows}} is
true, it will proceed to send next request at which point the {{RSRpcServices}} will throw
{{UnknownScannerException}}. The protobuf client compatibility is maintained but expected
behavior is modified.

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