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Devaraj Das commented on HBASE-9321: ------------------------------------ Right, we should be able to cache the currentuser on the Connection. > Contention getting the current user in RpcClient$Connection.writeRequest > ------------------------------------------------------------------------ > > Key: HBASE-9321 > URL: https://issues.apache.org/jira/browse/HBASE-9321 > Project: HBase > Issue Type: Bug > Affects Versions: 0.95.2 > Reporter: Jean-Daniel Cryans > Fix For: 0.98.0, 0.96.0 > > > I've been running tests on clusters with "lots" of regions, about 400, and > I'm seeing weird contention in the client. > This one I see a lot, hundreds and sometimes thousands of threads are blocked > like this: > {noformat} > "htable-pool4-t74" daemon prio=10 tid=0x00007f2254114000 nid=0x2a99 waiting > for monitor entry [0x00007f21f9e94000] > java.lang.Thread.State: BLOCKED (on object monitor) > at > org.apache.hadoop.security.UserGroupInformation.getCurrentUser(UserGroupInformation.java:466) > - waiting to lock <0x00000000fb5ad000> (a java.lang.Class for > org.apache.hadoop.security.UserGroupInformation) > at > org.apache.hadoop.hbase.ipc.RpcClient$Connection.writeRequest(RpcClient.java:1013) > at org.apache.hadoop.hbase.ipc.RpcClient.call(RpcClient.java:1407) > at > org.apache.hadoop.hbase.ipc.RpcClient.callBlockingMethod(RpcClient.java:1634) > at > org.apache.hadoop.hbase.ipc.RpcClient$BlockingRpcChannelImplementation.callBlockingMethod(RpcClient.java:1691) > at > org.apache.hadoop.hbase.protobuf.generated.ClientProtos$ClientService$BlockingStub.multi(ClientProtos.java:27339) > at > org.apache.hadoop.hbase.client.MultiServerCallable.call(MultiServerCallable.java:105) > at > org.apache.hadoop.hbase.client.MultiServerCallable.call(MultiServerCallable.java:43) > at > org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:183) > {noformat} > While the holder is doing this: > {noformat} > "htable-pool17-t55" daemon prio=10 tid=0x00007f2244408000 nid=0x2a98 runnable > [0x00007f21f9f95000] > java.lang.Thread.State: RUNNABLE > at java.security.AccessController.getStackAccessControlContext(Native > Method) > at java.security.AccessController.getContext(AccessController.java:487) > at > org.apache.hadoop.security.UserGroupInformation.getCurrentUser(UserGroupInformation.java:466) > - locked <0x00000000fb5ad000> (a java.lang.Class for > org.apache.hadoop.security.UserGroupInformation) > at > org.apache.hadoop.hbase.ipc.RpcClient$Connection.writeRequest(RpcClient.java:1013) > at org.apache.hadoop.hbase.ipc.RpcClient.call(RpcClient.java:1407) > at > org.apache.hadoop.hbase.ipc.RpcClient.callBlockingMethod(RpcClient.java:1634) > at > org.apache.hadoop.hbase.ipc.RpcClient$BlockingRpcChannelImplementation.callBlockingMethod(RpcClient.java:1691) > at > org.apache.hadoop.hbase.protobuf.generated.ClientProtos$ClientService$BlockingStub.multi(ClientProtos.java:27339) > at > org.apache.hadoop.hbase.client.MultiServerCallable.call(MultiServerCallable.java:105) > at > org.apache.hadoop.hbase.client.MultiServerCallable.call(MultiServerCallable.java:43) > at > org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:183) > {noformat} -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira