[HADOOP-15121] Encounter NullPointerException when using DecayRpcScheduler

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.8.2
• Fix Version/s: 3.1.0, 2.10.0, 3.0.1, 2.9.2, 2.8.5
• Target Version/s: 2.8.2
• Assignee: Tao Jie
• Reporter: Tao Jie
• Created: 15/Dec/17 07:41
• Updated: 09/Jul/18 20:29
• Resolved: 24/Jan/18 19:12

Description

I set ipc.8020.scheduler.impl to org.apache.hadoop.ipc.DecayRpcScheduler, but got excetion in namenode:

2017-12-15 15:26:34,662 ERROR impl.MetricsSourceAdapter (MetricsSourceAdapter.java:getMetrics(202)) - Error getting metrics from source DecayRpcSchedulerMetrics2.ipc.8020
java.lang.NullPointerException
        at org.apache.hadoop.ipc.DecayRpcScheduler$MetricsProxy.getMetrics(DecayRpcScheduler.java:781)
        at org.apache.hadoop.metrics2.impl.MetricsSourceAdapter.getMetrics(MetricsSourceAdapter.java:199)
        at org.apache.hadoop.metrics2.impl.MetricsSourceAdapter.updateJmxCache(MetricsSourceAdapter.java:182)
        at org.apache.hadoop.metrics2.impl.MetricsSourceAdapter.getMBeanInfo(MetricsSourceAdapter.java:155)
        at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.getNewMBeanClassName(DefaultMBeanServerInterceptor.java:333)
        at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:319)
        at com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(JmxMBeanServer.java:522)
        at org.apache.hadoop.metrics2.util.MBeans.register(MBeans.java:66)
        at org.apache.hadoop.metrics2.impl.MetricsSourceAdapter.startMBeans(MetricsSourceAdapter.java:222)
        at org.apache.hadoop.metrics2.impl.MetricsSourceAdapter.start(MetricsSourceAdapter.java:100)
        at org.apache.hadoop.metrics2.impl.MetricsSystemImpl.registerSource(MetricsSystemImpl.java:268)
        at org.apache.hadoop.metrics2.impl.MetricsSystemImpl.register(MetricsSystemImpl.java:233)
        at org.apache.hadoop.ipc.DecayRpcScheduler$MetricsProxy.registerMetrics2Source(DecayRpcScheduler.java:709)
        at org.apache.hadoop.ipc.DecayRpcScheduler$MetricsProxy.<init>(DecayRpcScheduler.java:685)
        at org.apache.hadoop.ipc.DecayRpcScheduler$MetricsProxy.getInstance(DecayRpcScheduler.java:693)
        at org.apache.hadoop.ipc.DecayRpcScheduler.<init>(DecayRpcScheduler.java:236)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
        at org.apache.hadoop.ipc.CallQueueManager.createScheduler(CallQueueManager.java:102)
        at org.apache.hadoop.ipc.CallQueueManager.<init>(CallQueueManager.java:76)
        at org.apache.hadoop.ipc.Server.<init>(Server.java:2612)
        at org.apache.hadoop.ipc.RPC$Server.<init>(RPC.java:958)
        at org.apache.hadoop.ipc.ProtobufRpcEngine$Server.<init>(ProtobufRpcEngine.java:374)
        at org.apache.hadoop.ipc.ProtobufRpcEngine.getServer(ProtobufRpcEngine.java:349)
        at org.apache.hadoop.ipc.RPC$Builder.build(RPC.java:800)
at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.<init>(NameNodeRpcServer.java:415)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.createRpcServer(NameNode.java:755)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:697)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:905)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:884)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1610)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1678)

It seems that metricsProxy in DecayRpcScheduler should initiate its delegate field in its Initialization method

Issue Links

• relates to: HADOOP-13159 Fix potential NPE in Metrics2 source for DecayRpcScheduler