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https://issues.apache.org/jira/browse/HBASE-26812?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17513864#comment-17513864
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chenglei edited comment on HBASE-26812 at 3/29/22, 1:45 PM:
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[~larsh],thank you very much for reply, I have write a test for master to
verify the {{User}} problem, and I find in {{master}} the behavior is the same
even though it create a real {{Connection}} instead of
{{ShortCircuitingClusterConnection}}, that is to say, in master, if we {{scan}}
regions in {{CP}}, when the target {{RegionServer}} receives the request , it
executes {{scan}} as the System User, not the original client, that is because
in master, when we invoke {{RegionCoprocessorEnvironment.createConnection}}, we
use following code, {{UserProvider.instantiate(conf).getCurrent()}} return the
System User, not the current RPC request {{User}}:
{code:java}
public Connection createConnection(Configuration conf) throws IOException {
User user = UserProvider.instantiate(conf).getCurrent();
return ConnectionFactory.createConnection(conf, null, user);
}
{code}
So , for the {{User}} problem in {{CP}}, the behavior is same for is 2.x and
master, both 2.x and master create a {{Connection}} in {{CP}} as the System
{{User}}, not the client {{User}}.
I have updated the PR.
was (Author: comnetwork):
[~larsh],thank you very much for reply, I have write a test for master to
verify the {{User}} problem, and I find in {{master}} the behavior is the same
even though it create a real {{Connection}} instead of
{{ShortCircuitingClusterConnection}}, that is to say, in master, if we {{scan}}
regions in {{CP}}, when the target {{RegionServer}} receives the request , it
executes {{scan}} as the System User, not the original client, that is because
in master, when we invoke {{RegionCoprocessorEnvironment.createConnection}},we
use following code,{{UserProvider.instantiate(conf).getCurrent()}} return the
System User, not the current RPC request {{User}}:
{code:java}
public Connection createConnection(Configuration conf) throws IOException {
User user = UserProvider.instantiate(conf).getCurrent();
return ConnectionFactory.createConnection(conf, null, user);
}
{code}
So , for the {{User}} problem in {{CP}}, the behavior is same for is 2.x and
master, both 2.x and master create a {{Connection}} in {{CP}} as the System
{{User}}, not the client {{User}}.
I have updated the PR.
> 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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