HADOOP-13362. DefaultMetricsSystem leaks the source name when a source unregisters. Contributed by Junping Du

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -12,6 +12,9 @@ Release 2.7.4 - UNRELEASED
 
   BUG FIXES
 
+    HADOOP-13362. DefaultMetricsSystem leaks the source name when a source
+    unregisters (Junping Du via jlowe)
+
 Release 2.7.3 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsSystemImpl.java

@@ -255,6 +255,7 @@ public class MetricsSystemImpl extends MetricsSystem implements MetricsSource {
     if (namedCallbacks.containsKey(name)) {
       namedCallbacks.remove(name);
     }
+    DefaultMetricsSystem.removeSourceName(name);
   }
 
   synchronized

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/lib/DefaultMetricsSystem.java

@@ -107,6 +107,11 @@ public enum DefaultMetricsSystem {
     INSTANCE.removeObjectName(name.toString());
   }
 
+  @InterfaceAudience.Private
+  public static void removeSourceName(String name) {
+    INSTANCE.removeSource(name);
+  }
+
   @InterfaceAudience.Private
   public static String sourceName(String name, boolean dupOK) {
     return INSTANCE.newSourceName(name, dupOK);
@@ -127,6 +132,10 @@ public enum DefaultMetricsSystem {
     mBeanNames.map.remove(name);
   }
 
+  synchronized void removeSource(String name) {
+    sourceNames.map.remove(name);
+  }
+
   synchronized String newSourceName(String name, boolean dupOK) {
     if (sourceNames.map.containsKey(name)) {
       if (dupOK) {

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/monitor/TestContainerMetrics.java

@@ -136,7 +136,6 @@ public class TestContainerMetrics {
     system.sampleMetrics();
     system.sampleMetrics();
     Thread.sleep(100);
-    system.stop();
     // verify metrics1 is unregistered
     assertTrue(metrics1 != ContainerMetrics.forContainer(
         system, containerId1, 1, 0));
@@ -146,6 +145,9 @@ public class TestContainerMetrics {
     // verify metrics3 is still registered
     assertTrue(metrics3 == ContainerMetrics.forContainer(
         system, containerId3, 1, 0));
+    // move stop() to the end to verify registering containerId1 and
+    // containerId2 won't get MetricsException thrown.
+    system.stop();
     system.shutdown();
   }
 }