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https://issues.apache.org/jira/browse/HBASE-26812?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17503383#comment-17503383
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chenglei edited comment on HBASE-26812 at 3/9/22, 11:25 AM:
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[~larsh], when I read the code,
{{RegionCoprocessorEnvironment.createConnection... getTable(...).}} is in
Phoenix CP for a region scanner, so there is currentCall context in current
thread, and the {{RegionScannerImpl}} created by Phoenix CP is not closed
because the existing currentCall context ,and it could not close because close
would make the DBB released early.
If there is no currentCall context in current thread, the table.get would close
RegionScanner at the end of the method.
was (Author: comnetwork):
[~larsh], when I read the code,
{{RegionCoprocessorEnvironment.createConnection... getTable(...).}} is in
Phoenix CP for a region scanner, so there is currentCall context in current
thread, and the {{RegionScannerImpl}} created by Phoenix CP is not closed
because the existing currentCall context ,and it could not close because close
would make the DBB released early.
> 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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