[HADOOP-10143] replace WritableFactories's hashmap with ConcurrentHashMap

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.0-alpha, 2.2.0
• Fix Version/s: 2.3.0
• Component/s: io
• Hadoop Flags: Reviewed
• Assignee: Liang Xie
• Reporter: Liang Xie
• Created: 04/Dec/13 07:58
• Updated: 03/Sep/14 23:33
• Resolved: 21/Jan/14 05:17

Description

We observed a lock contend hotspot from a HBase cluster:

"IPC Reader 9 on port 12600" daemon prio=10 tid=0x00007f85b8aceed0 nid=0x4be8 waiting for monitor entry [0x00007f8501c57000]
java.lang.Thread.State: BLOCKED (on object monitor)
at org.apache.hadoop.io.WritableFactories.getFactory(WritableFactories.java:44)

• locked <0x00000007fd1328a8> (a java.lang.Class for org.apache.hadoop.io.WritableFactories)
  at org.apache.hadoop.io.WritableFactories.newInstance(WritableFactories.java:49)
  at org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:680)
  at org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:586)
  at org.apache.hadoop.hbase.client.MultiAction.readFields(MultiAction.java:116)
  at org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:682)
  at org.apache.hadoop.hbase.ipc.Invocation.readFields(Invocation.java:126)
  at org.apache.hadoop.hbase.ipc.SecureServer$SecureConnection.processData(SecureServer.java:618)
  at org.apache.hadoop.hbase.ipc.SecureServer$SecureConnection.processOneRpc(SecureServer.java:596)
  at org.apache.hadoop.hbase.ipc.SecureServer$SecureConnection.saslReadAndProcess(SecureServer.java:362)
  at org.apache.hadoop.hbase.ipc.SecureServer$SecureConnection.readAndProcess(SecureServer.java:492)
  at org.apache.hadoop.hbase.ipc.HBaseServer$Listener.doRead(HBaseServer.java:770)
  at org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader.doRunLoop(HBaseServer.java:561)
• locked <0x000000043da3fea0> (a org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader)
  at org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader.run(HBaseServer.java:536)
  at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
  at java.lang.Thread.run(Thread.java:662)

"IPC Reader 7 on port 12600" daemon prio=10 tid=0x00007f85b8a99df0 nid=0x4be6 waiting for monitor entry [0x00007f8501cd9000]
java.lang.Thread.State: BLOCKED (on object monitor)
at org.apache.hadoop.io.WritableFactories.getFactory(WritableFactories.java:44)

• locked <0x00000007fd1328a8> (a java.lang.Class for org.apache.hadoop.io.WritableFactories)
  at org.apache.hadoop.io.WritableFactories.newInstance(WritableFactories.java:49)
  at org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:680)
  at org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:586)
  at org.apache.hadoop.hbase.client.MultiAction.readFields(MultiAction.java:116)
  at org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:682)
  at org.apache.hadoop.hbase.ipc.Invocation.readFields(Invocation.java:126)
  at org.apache.hadoop.hbase.ipc.SecureServer$SecureConnection.processData(SecureServer.java:618)
  at org.apache.hadoop.hbase.ipc.SecureServer$SecureConnection.processOneRpc(SecureServer.java:596)
  at org.apache.hadoop.hbase.ipc.SecureServer$SecureConnection.saslReadAndProcess(SecureServer.java:362)
  at org.apache.hadoop.hbase.ipc.SecureServer$SecureConnection.readAndProcess(SecureServer.java:492)
  at org.apache.hadoop.hbase.ipc.HBaseServer$Listener.doRead(HBaseServer.java:770)
  at org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader.doRunLoop(HBaseServer.java:561)
• locked <0x000000043da232e8> (a org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader)
  at org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader.run(HBaseServer.java:536)
  at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
  at java.lang.Thread.run(Thread.java:662)

"IPC Reader 5 on port 12600" daemon prio=10 tid=0x00007f85b8a64d40 nid=0x4be2 runnable [0x00007f8501d5b000]
java.lang.Thread.State: RUNNABLE
at org.apache.hadoop.io.WritableFactories.getFactory(WritableFactories.java:44)

• locked <0x00000007fd1328a8> (a java.lang.Class for org.apache.hadoop.io.WritableFactories)
  at org.apache.hadoop.io.WritableFactories.newInstance(WritableFactories.java:49)
  at org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:680)
  at org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:586)
  at org.apache.hadoop.hbase.client.Action.readFields(Action.java:103)
  at org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:682)
  at org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:586)
  at org.apache.hadoop.hbase.client.MultiAction.readFields(MultiAction.java:116)
  at org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:682)
  at org.apache.hadoop.hbase.ipc.Invocation.readFields(Invocation.java:126)
  at org.apache.hadoop.hbase.ipc.SecureServer$SecureConnection.processData(SecureServer.java:618)
  at org.apache.hadoop.hbase.ipc.SecureServer$SecureConnection.processOneRpc(SecureServer.java:596)
  at org.apache.hadoop.hbase.ipc.SecureServer$SecureConnection.saslReadAndProcess(SecureServer.java:362)
  at org.apache.hadoop.hbase.ipc.SecureServer$SecureConnection.readAndProcess(SecureServer.java:492)
  at org.apache.hadoop.hbase.ipc.HBaseServer$Listener.doRead(HBaseServer.java:770)
  at org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader.doRunLoop(HBaseServer.java:561)
• locked <0x000000043da27300> (a org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader)
  at org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader.run(HBaseServer.java:536)
  at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
  at java.lang.Thread.run(Thread.java:662)

All those three threads just wanted to get/read the factory, so to me, it looks like a perfect use case for ConcurrentHashMap here.