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https://issues.apache.org/jira/browse/HBASE-26812?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17509457#comment-17509457
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chenglei edited comment on HBASE-26812 at 3/20/22, 1:33 PM:
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[~larsh], I have open a jira HBASE-26869 to fix the problem that when there is
no {{RpcCallContext}} , {{RSRpcServices.scan}} does not deep clone the result
cells and the {{RegionScanner}} is not shipped when {{RSRpcServices.scan}}
return partial results. No matter {{ShortCircuitingClusterConnection}} should
be removed or not, I think this {{RSRpcServices.scan}} problem should fix for
future maintainability.
But for the {{User}} problem your mentioned, seems that it is hard to fix it
because when the {{HTable}} invokes {{RSRpcServices.scan}} and
{{RSRpcServices.multi}}, they are in threadPool, so there is no
{{RpcCallContext}}，let alone {{User}}. If {{User}} is so important, removing
{{ShortCircuitingClusterConnection}} seems is a more acceptable way.
was (Author: comnetwork):
[~larsh], I have open a jira HBASE-26869 to fix the problem that when there is
no {{RpcCallContext}} , {{RSRpcServices.scan}} does not deep clone the result
cells and the {{RegionScanner}} is not shipped when {{RSRpcServices.scan}}
return partial results. No matter {{ShortCircuitingClusterConnection}} should
be removed or not, I think we should fix this {{RSRpcServices.scan}} problem
for future maintainability.
But for the {{User}} problem your mentioned, seems that it is hard to fix it
because when the {{HTable}} invokes {{RSRpcServices.scan}} and
{{RSRpcServices.multi}}, they are in threadPool, so there is no
{{RpcCallContext}}，let alone {{User}}. If {{User}} is so important, removing
{{ShortCircuitingClusterConnection}} seems is a more acceptable way.
> ShortCircuitingClusterConnection fails to close RegionScanners when making
> short-circuited calls
> ------------------------------------------------------------------------------------------------
>
> Key: HBASE-26812
> URL: https://issues.apache.org/jira/browse/HBASE-26812
> Project: HBase
> Issue Type: Bug
> Affects Versions: 2.4.9
> Reporter: Lars Hofhansl
> Priority: Critical
>
> Just ran into this on the Phoenix side.
> We retrieve a Connection via
> {{{}RegionCoprocessorEnvironment.createConnection... getTable(...){}}}. And
> then call get on that table. The Get's key happens to be local. Now each call
> to table.get() leaves an open StoreScanner around forever. (verified with a
> memory profiler).
> There references are held via
> RegionScannerImpl.storeHeap.scannersForDelayedClose. Eventially the
> RegionServer goes into a GC of death and can only ended with kill -9.
> The reason appears to be that in this case there is no currentCall context.
> Some time in 2.x the Rpc handler/call was made responsible for closing open
> region scanners, but we forgot to handle {{ShortCircuitingClusterConnection}}
> It's not immediately clear how to fix this. But it does make
> ShortCircuitingClusterConnection useless and dangerous. If you use it, you
> *will* create a giant memory leak.
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