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https://issues.apache.org/jira/browse/HBASE-18042?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16011327#comment-16011327
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Benoit Sigoure commented on HBASE-18042:
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We can easily update AsyncHBase to accommodate to the change however I would
like to voice disagreement with this statement:
{quote}
It is an unfortunate thing that we have broken the semantics, but in general
this is "allowed".
{quote}
Such semantic changes are like breaking API changes, they are, well, breaking
changes. Not cool.
One of the challenges with AsyncHBase is that it has to work with all versions
of HBase. Since {{more_results_in_region}} was already there in 1.2 but needs
to be handled differently in 1.3, that makes it kinda hard for AsyncHBase to
know how, exactly, to deal with this flag being set, right?
> 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
> Affects Versions: 1.3.1
> Reporter: Karan Mehta
> Assignee: 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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