HADOOP-18364. All method metrics related to the RPC protocol should be initialized. (#4624). Contributed by Shuyan Zhang.

Reviewed-by: Erik Krogen <xkrogen@apache.org>
Reviewed-by: Chao Sun <sunchao@apache.org>
Signed-off-by: He Xiaoqiao <hexiaoqiao@apache.org>

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

@@ -72,7 +72,7 @@ public class MutableRatesWithAggregation extends MutableMetric {
       return;
     }
     protocolCache.add(protocol);
-    for (Method method : protocol.getDeclaredMethods()) {
+    for (Method method : protocol.getMethods()) {
       String name = method.getName();
       LOG.debug(name);
       addMetricIfNotExists(name);

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/metrics/TestNameNodeMetrics.java

@@ -48,6 +48,9 @@ import java.util.ArrayList;
 import java.util.EnumSet;
 import java.util.List;
 import java.util.Random;
+
+import org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer;
+import org.apache.hadoop.ipc.metrics.RpcDetailedMetrics;
 import org.apache.hadoop.thirdparty.com.google.common.collect.ImmutableList;
 
 import org.slf4j.Logger;
@@ -1128,4 +1131,14 @@ public class TestNameNodeMetrics {
     }
 
   }
+
+  @Test
+  public void testNNRPCMetricIntegrity() {
+    RpcDetailedMetrics metrics =
+        ((NameNodeRpcServer) cluster.getNameNode()
+            .getRpcServer()).getClientRpcServer().getRpcDetailedMetrics();
+    MetricsRecordBuilder rb = getMetrics(metrics.name());
+    // CommitBlockSynchronizationNumOps should exist.
+    assertCounter("CommitBlockSynchronizationNumOps", 0L, rb);
+  }
 }