Josh Elser created ACCUMULO-3853: ------------------------------------ Summary: Contention around ConcurrentLinkedQueue.size() in AsyncSpanReceiver Key: ACCUMULO-3853 URL: https://issues.apache.org/jira/browse/ACCUMULO-3853 Project: Accumulo Issue Type: Bug Components: trace Affects Versions: 1.7.0 Reporter: Josh Elser Assignee: Josh Elser Fix For: 1.8.0, 1.7.1
Trying to debug slowness in the replication merkle test, I saw a lot of stack traces sitting here: {noformat} "replication task 1" #297 daemon prio=5 os_prio=0 tid=0x0000000004624000 nid=0x6b46 runnable [0x00007ff8867b6000] java.lang.Thread.State: RUNNABLE at java.util.concurrent.ConcurrentLinkedQueue.size(ConcurrentLinkedQueue.java:450) at org.apache.accumulo.tracer.AsyncSpanReceiver.receiveSpan(AsyncSpanReceiver.java:171) at org.apache.htrace.Tracer.deliver(Tracer.java:81) at org.apache.htrace.impl.MilliSpan.stop(MilliSpan.java:177) - locked <0x00000000a7fe3560> (a org.apache.htrace.impl.MilliSpan) at org.apache.htrace.TraceScope.close(TraceScope.java:78) at org.apache.hadoop.hdfs.DFSInputStream.read(DFSInputStream.java:898) - locked <0x00000000b0086118> (a org.apache.hadoop.hdfs.DFSInputStream) at java.io.DataInputStream.readFully(DataInputStream.java:195) at java.io.DataInputStream.readFully(DataInputStream.java:169) at org.apache.accumulo.core.data.Mutation.readFields(Mutation.java:965) at org.apache.accumulo.server.data.ServerMutation.readFields(ServerMutation.java:52) at org.apache.accumulo.tserver.logger.LogFileValue.readFields(LogFileValue.java:45) at org.apache.accumulo.tserver.replication.AccumuloReplicaSystem.getWalEdits(AccumuloReplicaSystem.java:702) at org.apache.accumulo.tserver.replication.AccumuloReplicaSystem$WalClientExecReturn.execute(AccumuloReplicaSystem.java:531) at org.apache.accumulo.tserver.replication.AccumuloReplicaSystem$WalClientExecReturn.execute(AccumuloReplicaSystem.java:506) at org.apache.accumulo.core.client.impl.ReplicationClient.executeServicerWithReturn(ReplicationClient.java:189) at org.apache.accumulo.tserver.replication.AccumuloReplicaSystem.replicateLogs(AccumuloReplicaSystem.java:429) at org.apache.accumulo.tserver.replication.AccumuloReplicaSystem._replicate(AccumuloReplicaSystem.java:291) at org.apache.accumulo.tserver.replication.AccumuloReplicaSystem.replicate(AccumuloReplicaSystem.java:212) at org.apache.accumulo.tserver.replication.ReplicationProcessor.process(ReplicationProcessor.java:134) at org.apache.accumulo.server.zookeeper.DistributedWorkQueue$1.run(DistributedWorkQueue.java:107) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at org.apache.accumulo.fate.util.LoggingRunnable.run(LoggingRunnable.java:35) at java.lang.Thread.run(Thread.java:745) Locked ownable synchronizers: - <0x00000000b00dbf48> (a java.util.concurrent.ThreadPoolExecutor$Worker) {noformat} Seems like this might still be related to HDFS-8069, but one odd thing is that we were sitting in the size() method. For those who don't remember, size() is a big o N operation on ConcurrentLinkedQueue. Calling the size() method every time we receive a new span is a little nasty. -- This message was sent by Atlassian JIRA (v6.3.4#6332)