HADOOP-11295. RPC Server Reader thread can't shutdown if RPCCallQueue is full. Contributed by Ming Ma.

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

@@ -953,6 +953,9 @@ Release 2.7.0 - UNRELEASED
     HADOOP-11570. S3AInputStream.close() downloads the remaining bytes of
     the object from S3. (Dan Hecht via stevel).
 
+    HADOOP-11295. RPC Server Reader thread can't shutdown if RPCCallQueue is
+    full. (Ming Ma via kihwal)
+
 Release 2.6.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/Server.java

@@ -666,6 +666,7 @@ void shutdown() {
         assert !running;
         readSelector.wakeup();
         try {
+          super.interrupt();
           super.join();
         } catch (InterruptedException ie) {
           Thread.currentThread().interrupt();

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/ipc/TestRPC.java

@@ -38,9 +38,16 @@
 import java.net.ConnectException;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.Callable;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.CyclicBarrier;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
 
@@ -1013,6 +1020,67 @@ public void testRpcMetrics() throws Exception {
     }
   }
 
+  /**
+   *  Verify the RPC server can shutdown properly when callQueue is full.
+   */
+  @Test (timeout=30000)
+  public void testRPCServerShutdown() throws Exception {
+    final int numClients = 3;
+    final List<Future<Void>> res = new ArrayList<Future<Void>>();
+    final ExecutorService executorService =
+        Executors.newFixedThreadPool(numClients);
+    final Configuration conf = new Configuration();
+    conf.setInt(CommonConfigurationKeys.IPC_CLIENT_CONNECT_MAX_RETRIES_KEY, 0);
+    final Server server = new RPC.Builder(conf)
+        .setProtocol(TestProtocol.class).setInstance(new TestImpl())
+        .setBindAddress(ADDRESS).setPort(0)
+        .setQueueSizePerHandler(1).setNumHandlers(1).setVerbose(true)
+        .build();
+    server.start();
+
+    final TestProtocol proxy =
+        RPC.getProxy(TestProtocol.class, TestProtocol.versionID,
+            NetUtils.getConnectAddress(server), conf);
+    try {
+      // start a sleep RPC call to consume the only handler thread.
+      // Start another sleep RPC call to make callQueue full.
+      // Start another sleep RPC call to make reader thread block on CallQueue.
+      for (int i = 0; i < numClients; i++) {
+        res.add(executorService.submit(
+            new Callable<Void>() {
+              @Override
+              public Void call() throws IOException, InterruptedException {
+                proxy.sleep(100000);
+                return null;
+              }
+            }));
+      }
+      while (server.getCallQueueLen() != 1
+          && countThreads(CallQueueManager.class.getName()) != 1
+          && countThreads(TestProtocol.class.getName()) != 1) {
+        Thread.sleep(100);
+      }
+    } finally {
+      try {
+        server.stop();
+        assertEquals("Not enough clients", numClients, res.size());
+        for (Future<Void> f : res) {
+          try {
+            f.get();
+            fail("Future get should not return");
+          } catch (ExecutionException e) {
+            assertTrue("Unexpected exception: " + e,
+                e.getCause() instanceof IOException);
+            LOG.info("Expected exception", e.getCause());
+          }
+        }
+      } finally {
+        RPC.stopProxy(proxy);
+        executorService.shutdown();
+      }
+    }
+  }
+
   public static void main(String[] args) throws IOException {
     new TestRPC().testCallsInternal(conf);