HDFS-11970. Ozone: TestXceiverClientManager.testFreeByEviction fails occasionally. Contributed by Mukul Kumar Singh.

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/scm/XceiverClientManager.java

@@ -100,15 +100,15 @@ public class XceiverClientManager {
   }
 
   /**
-   * Acquires a SharedXceiverClient connected to a container capable of
+   * Acquires a XceiverClientSpi connected to a container capable of
    * storing the specified key.
    *
-   * If there is already a cached SharedXceiverClient, simply return
+   * If there is already a cached XceiverClientSpi, simply return
    * the cached otherwise create a new one.
    *
    * @param pipeline the container pipeline for the client connection
-   * @return SharedXceiverClient connected to a container
-   * @throws IOException if an SharedXceiverClient cannot be acquired
+   * @return XceiverClientSpi connected to a container
+   * @throws IOException if a XceiverClientSpi cannot be acquired
    */
   public XceiverClientSpi acquireClient(Pipeline pipeline)
       throws IOException {
@@ -124,7 +124,7 @@ public class XceiverClientManager {
   }
 
   /**
-   * Releases an SharedXceiverClient after use.
+   * Releases a XceiverClientSpi after use.
    *
    * @param client client to release
    */

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/ozone/scm/TestXceiverClientManager.java

@@ -96,7 +96,7 @@ public class TestXceiverClientManager {
   @Test
   public void testFreeByReference() throws IOException {
     OzoneConfiguration conf = new OzoneConfiguration();
-    conf.setInt(SCM_CONTAINER_CLIENT_MAX_SIZE_KEY, 2);
+    conf.setInt(SCM_CONTAINER_CLIENT_MAX_SIZE_KEY, 1);
     XceiverClientManager clientManager = new XceiverClientManager(conf);
     Cache<String, XceiverClientSpi> cache =
         clientManager.getClientCache();
@@ -118,14 +118,6 @@ public class TestXceiverClientManager {
         client2.getPipeline().getContainerName());
     Assert.assertNotEquals(client1, client2);
 
-    String containerName3 = "container" + RandomStringUtils.randomNumeric(10);
-    Pipeline pipeline3 =
-        storageContainerLocationClient.allocateContainer(containerName3);
-    XceiverClientSpi client3 = clientManager.acquireClient(pipeline3);
-    Assert.assertEquals(client3.getRefcount(), 1);
-    Assert.assertEquals(containerName3,
-        client3.getPipeline().getContainerName());
-
     // least recent container (i.e containerName1) is evicted
     XceiverClientSpi nonExistent1 = cache.getIfPresent(containerName1);
     Assert.assertEquals(nonExistent1, null);
@@ -140,13 +132,12 @@ public class TestXceiverClientManager {
     exception.expectMessage("This channel is not connected.");
     ContainerProtocolCalls.createContainer(client1,  traceID1);
     clientManager.releaseClient(client2);
-    clientManager.releaseClient(client3);
   }
 
   @Test
   public void testFreeByEviction() throws IOException {
     OzoneConfiguration conf = new OzoneConfiguration();
-    conf.setInt(SCM_CONTAINER_CLIENT_MAX_SIZE_KEY, 2);
+    conf.setInt(SCM_CONTAINER_CLIENT_MAX_SIZE_KEY, 1);
     XceiverClientManager clientManager = new XceiverClientManager(conf);
     Cache<String, XceiverClientSpi> cache =
         clientManager.getClientCache();
@@ -159,6 +150,9 @@ public class TestXceiverClientManager {
     Assert.assertEquals(containerName1,
         client1.getPipeline().getContainerName());
 
+    clientManager.releaseClient(client1);
+    Assert.assertEquals(client1.getRefcount(), 0);
+
     String containerName2 = "container" + RandomStringUtils.randomNumeric(10);
     Pipeline pipeline2 =
         storageContainerLocationClient.allocateContainer(containerName2);
@@ -168,16 +162,6 @@ public class TestXceiverClientManager {
         client2.getPipeline().getContainerName());
     Assert.assertNotEquals(client1, client2);
 
-    clientManager.releaseClient(client1);
-    Assert.assertEquals(client1.getRefcount(), 0);
-
-    String containerName3 = "container" + RandomStringUtils.randomNumeric(10);
-    Pipeline pipeline3 =
-        storageContainerLocationClient.allocateContainer(containerName3);
-    XceiverClientSpi client3 = clientManager.acquireClient(pipeline3);
-    Assert.assertEquals(client3.getRefcount(), 1);
-    Assert.assertEquals(containerName3,
-        client3.getPipeline().getContainerName());
 
     // now client 1 should be evicted
     XceiverClientSpi nonExistent = cache.getIfPresent(containerName1);
@@ -189,6 +173,5 @@ public class TestXceiverClientManager {
     exception.expectMessage("This channel is not connected.");
     ContainerProtocolCalls.createContainer(client1, traceID2);
     clientManager.releaseClient(client2);
-    clientManager.releaseClient(client3);
   }
 }