svn merge -c 1508220 FIXES: MAPREDUCE-5411. Refresh size of loaded job cache on history server. Contributed by Ashwin Shankar

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1508224 13f79535-47bb-0310-9956-ffa450edef68

hadoop-mapreduce-project/CHANGES.txt

@@ -15,6 +15,9 @@ Release 2.3.0 - UNRELEASED
     MAPREDUCE-5386. Ability to refresh history server job retention and job
     cleaner settings (Ashwin Shankar via jlowe)
 
+    MAPREDUCE-5411. Refresh size of loaded job cache on history server (Ashwin
+    Shankar via jlowe)
+
   IMPROVEMENTS
 
   OPTIMIZATIONS

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/main/java/org/apache/hadoop/mapreduce/v2/hs/CachedHistoryStorage.java

@@ -40,6 +40,8 @@ import org.apache.hadoop.mapreduce.v2.jobhistory.JHAdminConfig;
 import org.apache.hadoop.service.AbstractService;
 import org.apache.hadoop.yarn.exceptions.YarnRuntimeException;
 
+import com.google.common.annotations.VisibleForTesting;
+
 /**
  * Manages an in memory cache of parsed Job History files.
  */
@@ -58,12 +60,16 @@ public class CachedHistoryStorage extends AbstractService implements
     this.hsManager = hsManager;
   }
 
-  @SuppressWarnings("serial")
   @Override
   public void serviceInit(Configuration conf) throws Exception {
     super.serviceInit(conf);
     LOG.info("CachedHistoryStorage Init");
 
+    createLoadedJobCache(conf);
+  }
+
+  @SuppressWarnings("serial")
+  private void createLoadedJobCache(Configuration conf) {
     loadedJobCacheSize = conf.getInt(
         JHAdminConfig.MR_HISTORY_LOADED_JOB_CACHE_SIZE,
         JHAdminConfig.DEFAULT_MR_HISTORY_LOADED_JOB_CACHE_SIZE);
@@ -76,11 +82,25 @@ public class CachedHistoryStorage extends AbstractService implements
       }
     });
   }
-
+  
+  public void refreshLoadedJobCache() {
+    if (getServiceState() == STATE.STARTED) {
+      setConfig(createConf());
+      createLoadedJobCache(getConfig());
+    } else {
+      LOG.warn("Failed to execute refreshLoadedJobCache: CachedHistoryStorage is not started");
+    }
+  }
+  
+  @VisibleForTesting
+  Configuration createConf() {
+    return new Configuration();
+  }
+  
   public CachedHistoryStorage() {
     super(CachedHistoryStorage.class.getName());
   }
-
+  
   private Job loadJob(HistoryFileInfo fileInfo) {
     try {
       Job job = fileInfo.loadJob();
@@ -98,6 +118,11 @@ public class CachedHistoryStorage extends AbstractService implements
     }
   }
 
+  @VisibleForTesting
+  Map<JobId, Job> getLoadedJobCache() {
+    return loadedJobCache;
+  }
+  
   @Override
   public Job getFullJob(JobId jobId) {
     if (LOG.isDebugEnabled()) {

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/main/java/org/apache/hadoop/mapreduce/v2/hs/JobHistory.java

@@ -51,6 +51,7 @@ import org.apache.hadoop.yarn.factory.providers.RecordFactoryProvider;
 import org.apache.hadoop.yarn.security.client.ClientToAMTokenSecretManager;
 import org.apache.hadoop.yarn.util.Clock;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.util.concurrent.ThreadFactoryBuilder;
 
 /**
@@ -97,9 +98,8 @@ public class JobHistory extends AbstractService implements HistoryContext {
       throw new YarnRuntimeException("Failed to intialize existing directories", e);
     }
 
-    storage = ReflectionUtils.newInstance(conf.getClass(
-        JHAdminConfig.MR_HISTORY_STORAGE, CachedHistoryStorage.class,
-        HistoryStorage.class), conf);
+    storage = createHistoryStorage();
+    
     if (storage instanceof Service) {
       ((Service) storage).init(conf);
     }
@@ -108,6 +108,12 @@ public class JobHistory extends AbstractService implements HistoryContext {
     super.serviceInit(conf);
   }
 
+  protected HistoryStorage createHistoryStorage() {
+    return ReflectionUtils.newInstance(conf.getClass(
+        JHAdminConfig.MR_HISTORY_STORAGE, CachedHistoryStorage.class,
+        HistoryStorage.class), conf);
+  }
+  
   protected HistoryFileManager createHistoryFileManager() {
     return new HistoryFileManager();
   }
@@ -229,6 +235,25 @@ public class JobHistory extends AbstractService implements HistoryContext {
     return storage.getAllPartialJobs();
   }
 
+  public void refreshLoadedJobCache() {
+    if (getServiceState() == STATE.STARTED) {
+      if (storage instanceof CachedHistoryStorage) {
+        ((CachedHistoryStorage) storage).refreshLoadedJobCache();
+      } else {
+        throw new UnsupportedOperationException(storage.getClass().getName()
+            + " is expected to be an instance of "
+            + CachedHistoryStorage.class.getName());
+      }
+    } else {
+      LOG.warn("Failed to execute refreshLoadedJobCache: JobHistory service is not started");
+    }
+  }
+
+  @VisibleForTesting
+  HistoryStorage getHistoryStorage() {
+    return storage;
+  }
+  
   /**
    * Look for a set of partial jobs.
    * 

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/main/java/org/apache/hadoop/mapreduce/v2/hs/client/HSAdmin.java

@@ -60,6 +60,8 @@ public class HSAdmin extends Configured implements Tool {
           .println("Usage: mapred hsadmin [-refreshSuperUserGroupsConfiguration]");
     } else if ("-refreshAdminAcls".equals(cmd)) {
       System.err.println("Usage: mapred hsadmin [-refreshAdminAcls]");
+    } else if ("-refreshLoadedJobCache".equals(cmd)) {
+      System.err.println("Usage: mapred hsadmin [-refreshLoadedJobCache]");
     } else if ("-refreshJobRetentionSettings".equals(cmd)) {
       System.err
           .println("Usage: mapred hsadmin [-refreshJobRetentionSettings]");
@@ -73,6 +75,7 @@ public class HSAdmin extends Configured implements Tool {
       System.err.println("           [-refreshUserToGroupsMappings]");
       System.err.println("           [-refreshSuperUserGroupsConfiguration]");
       System.err.println("           [-refreshAdminAcls]");
+      System.err.println("           [-refreshLoadedJobCache]");
       System.err.println("           [-refreshJobRetentionSettings]");
       System.err.println("           [-refreshLogRetentionSettings]");
       System.err.println("           [-getGroups [username]]");
@@ -89,6 +92,7 @@ public class HSAdmin extends Configured implements Tool {
         + " [-refreshUserToGroupsMappings]"
         + " [-refreshSuperUserGroupsConfiguration]"
         + " [-refreshAdminAcls]"
+        + " [-refreshLoadedJobCache]"
         + " [-refreshLogRetentionSettings]"
         + " [-refreshJobRetentionSettings]"
         + " [-getGroups [username]]" + " [-help [cmd]]\n";
@@ -99,13 +103,14 @@ public class HSAdmin extends Configured implements Tool {
 
     String refreshAdminAcls = "-refreshAdminAcls: Refresh acls for administration of Job history server\n";
 
+    String refreshLoadedJobCache = "-refreshLoadedJobCache: Refresh loaded job cache of Job history server\n";
+
     String refreshJobRetentionSettings = "-refreshJobRetentionSettings:" + 
         "Refresh job history period,job cleaner settings\n";
 
     String refreshLogRetentionSettings = "-refreshLogRetentionSettings:" + 
         "Refresh log retention period and log retention check interval\n";
     
-
     String getGroups = "-getGroups [username]: Get the groups which given user belongs to\n";
 
     String help = "-help [cmd]: \tDisplays help for the given command or all commands if none\n"
@@ -119,6 +124,8 @@ public class HSAdmin extends Configured implements Tool {
       System.out.println(refreshSuperUserGroupsConfiguration);
     } else if ("refreshAdminAcls".equals(cmd)) {
       System.out.println(refreshAdminAcls);
+    } else if ("refreshLoadedJobCache".equals(cmd)) {
+      System.out.println(refreshLoadedJobCache);
     } else if ("refreshJobRetentionSettings".equals(cmd)) {
       System.out.println(refreshJobRetentionSettings);
     } else if ("refreshLogRetentionSettings".equals(cmd)) {
@@ -130,6 +137,7 @@ public class HSAdmin extends Configured implements Tool {
       System.out.println(refreshUserToGroupsMappings);
       System.out.println(refreshSuperUserGroupsConfiguration);
       System.out.println(refreshAdminAcls);
+      System.out.println(refreshLoadedJobCache);
       System.out.println(refreshJobRetentionSettings);
       System.out.println(refreshLogRetentionSettings);
       System.out.println(getGroups);
@@ -221,6 +229,22 @@ public class HSAdmin extends Configured implements Tool {
     return 0;
   }
 
+  private int refreshLoadedJobCache() throws IOException {
+    // Refresh the loaded job cache
+    Configuration conf = getConf();
+    InetSocketAddress address = conf.getSocketAddr(
+        JHAdminConfig.JHS_ADMIN_ADDRESS,
+        JHAdminConfig.DEFAULT_JHS_ADMIN_ADDRESS,
+        JHAdminConfig.DEFAULT_JHS_ADMIN_PORT);
+
+    HSAdminRefreshProtocol refreshProtocol = HSProxies.createProxy(conf,
+        address, HSAdminRefreshProtocol.class,
+        UserGroupInformation.getCurrentUser());
+
+    refreshProtocol.refreshLoadedJobCache();
+    return 0;
+  }
+    
   private int refreshJobRetentionSettings() throws IOException {
     // Refresh job retention settings
     Configuration conf = getConf();
@@ -267,6 +291,7 @@ public class HSAdmin extends Configured implements Tool {
     if ("-refreshUserToGroupsMappings".equals(cmd)
         || "-refreshSuperUserGroupsConfiguration".equals(cmd)
         || "-refreshAdminAcls".equals(cmd)
+        || "-refreshLoadedJobCache".equals(cmd)
         || "-refreshJobRetentionSettings".equals(cmd)
         || "-refreshLogRetentionSettings".equals(cmd)) {
       if (args.length != 1) {
@@ -282,6 +307,8 @@ public class HSAdmin extends Configured implements Tool {
       exitCode = refreshSuperUserGroupsConfiguration();
     } else if ("-refreshAdminAcls".equals(cmd)) {
       exitCode = refreshAdminAcls();
+    } else if ("-refreshLoadedJobCache".equals(cmd)) {
+      exitCode = refreshLoadedJobCache();
     } else if ("-refreshJobRetentionSettings".equals(cmd)) {
       exitCode = refreshJobRetentionSettings();
     } else if ("-refreshLogRetentionSettings".equals(cmd)) {

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/main/java/org/apache/hadoop/mapreduce/v2/hs/protocol/HSAdminRefreshProtocol.java

@@ -40,6 +40,12 @@ public interface HSAdminRefreshProtocol {
    */
   public void refreshAdminAcls() throws IOException;
   
+  /**
+   * Refresh loaded job cache
+   * @throws IOException
+   */
+  public void refreshLoadedJobCache() throws IOException;
+
   /**
    * Refresh job retention settings.
    * 

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/main/java/org/apache/hadoop/mapreduce/v2/hs/protocolPB/HSAdminRefreshProtocolClientSideTranslatorPB.java

@@ -27,6 +27,7 @@ import org.apache.hadoop.ipc.ProtocolMetaInterface;
 import org.apache.hadoop.ipc.RPC;
 import org.apache.hadoop.ipc.RpcClientUtil;
 import org.apache.hadoop.mapreduce.v2.hs.proto.HSAdminRefreshProtocolProtos.RefreshAdminAclsRequestProto;
+import org.apache.hadoop.mapreduce.v2.hs.proto.HSAdminRefreshProtocolProtos.RefreshLoadedJobCacheRequestProto;
 import org.apache.hadoop.mapreduce.v2.hs.proto.HSAdminRefreshProtocolProtos.RefreshJobRetentionSettingsRequestProto;
 import org.apache.hadoop.mapreduce.v2.hs.proto.HSAdminRefreshProtocolProtos.RefreshLogRetentionSettingsRequestProto;
 import org.apache.hadoop.mapreduce.v2.hs.protocol.HSAdminRefreshProtocol;
@@ -46,6 +47,10 @@ public class HSAdminRefreshProtocolClientSideTranslatorPB implements
   private final static RefreshAdminAclsRequestProto 
     VOID_REFRESH_ADMIN_ACLS_REQUEST = RefreshAdminAclsRequestProto
       .newBuilder().build();
+
+  private final static RefreshLoadedJobCacheRequestProto 
+    VOID_REFRESH_LOADED_JOB_CACHE_REQUEST = RefreshLoadedJobCacheRequestProto
+      .newBuilder().build();
   
   private final static RefreshJobRetentionSettingsRequestProto 
     VOID_REFRESH_JOB_RETENTION_SETTINGS_REQUEST = 
@@ -75,6 +80,17 @@ public class HSAdminRefreshProtocolClientSideTranslatorPB implements
     }
   }
 
+
+  @Override
+  public void refreshLoadedJobCache() throws IOException {
+    try {
+      rpcProxy.refreshLoadedJobCache(NULL_CONTROLLER,
+          VOID_REFRESH_LOADED_JOB_CACHE_REQUEST);
+    } catch (ServiceException se) {
+      throw ProtobufHelper.getRemoteException(se);
+    }
+  }
+  
   @Override
   public void refreshJobRetentionSettings() throws IOException {
     try {
@@ -101,4 +117,5 @@ public class HSAdminRefreshProtocolClientSideTranslatorPB implements
         HSAdminRefreshProtocolPB.class, RPC.RpcKind.RPC_PROTOCOL_BUFFER,
         RPC.getProtocolVersion(HSAdminRefreshProtocolPB.class), methodName);
   }
+
 }

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/main/java/org/apache/hadoop/mapreduce/v2/hs/protocolPB/HSAdminRefreshProtocolServerSideTranslatorPB.java

@@ -23,6 +23,8 @@ import java.io.IOException;
 import org.apache.hadoop.classification.InterfaceAudience.Private;
 import org.apache.hadoop.mapreduce.v2.hs.proto.HSAdminRefreshProtocolProtos.RefreshAdminAclsResponseProto;
 import org.apache.hadoop.mapreduce.v2.hs.proto.HSAdminRefreshProtocolProtos.RefreshAdminAclsRequestProto;
+import org.apache.hadoop.mapreduce.v2.hs.proto.HSAdminRefreshProtocolProtos.RefreshLoadedJobCacheRequestProto;
+import org.apache.hadoop.mapreduce.v2.hs.proto.HSAdminRefreshProtocolProtos.RefreshLoadedJobCacheResponseProto;
 import org.apache.hadoop.mapreduce.v2.hs.proto.HSAdminRefreshProtocolProtos.RefreshJobRetentionSettingsRequestProto;
 import org.apache.hadoop.mapreduce.v2.hs.proto.HSAdminRefreshProtocolProtos.RefreshJobRetentionSettingsResponseProto;
 import org.apache.hadoop.mapreduce.v2.hs.proto.HSAdminRefreshProtocolProtos.RefreshLogRetentionSettingsRequestProto;
@@ -41,11 +43,15 @@ public class HSAdminRefreshProtocolServerSideTranslatorPB implements
   private final static RefreshAdminAclsResponseProto 
     VOID_REFRESH_ADMIN_ACLS_RESPONSE = RefreshAdminAclsResponseProto
       .newBuilder().build();
-  
+
+  private final static RefreshLoadedJobCacheResponseProto 
+    VOID_REFRESH_LOADED_JOB_CACHE_RESPONSE = RefreshLoadedJobCacheResponseProto
+      .newBuilder().build();
+
   private final static RefreshJobRetentionSettingsResponseProto 
     VOID_REFRESH_JOB_RETENTION_SETTINGS_RESPONSE = 
       RefreshJobRetentionSettingsResponseProto.newBuilder().build();
-  
+
   private final static RefreshLogRetentionSettingsResponseProto 
     VOID_REFRESH_LOG_RETENTION_SETTINGS_RESPONSE = 
       RefreshLogRetentionSettingsResponseProto.newBuilder().build();
@@ -67,6 +73,18 @@ public class HSAdminRefreshProtocolServerSideTranslatorPB implements
     return VOID_REFRESH_ADMIN_ACLS_RESPONSE;
   }
 
+  @Override
+  public RefreshLoadedJobCacheResponseProto refreshLoadedJobCache(
+      RpcController controller, RefreshLoadedJobCacheRequestProto request)
+      throws ServiceException {
+    try {
+      impl.refreshLoadedJobCache();
+    } catch (IOException e) {
+      throw new ServiceException(e);
+    }
+    return VOID_REFRESH_LOADED_JOB_CACHE_RESPONSE;
+  }
+
   @Override
   public RefreshJobRetentionSettingsResponseProto refreshJobRetentionSettings(
       RpcController controller, 

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/main/java/org/apache/hadoop/mapreduce/v2/hs/server/HSAdminServer.java

@@ -202,6 +202,22 @@ public class HSAdminServer extends AbstractService implements HSAdminProtocol {
         HISTORY_ADMIN_SERVER);
   }
 
+  @Override
+  public void refreshLoadedJobCache() throws IOException {
+    UserGroupInformation user = checkAcls("refreshLoadedJobCache");
+
+    try {
+      jobHistoryService.refreshLoadedJobCache();
+    } catch (UnsupportedOperationException e) {
+      HSAuditLogger.logFailure(user.getShortUserName(),
+          "refreshLoadedJobCache", adminAcl.toString(), HISTORY_ADMIN_SERVER,
+          e.getMessage());
+      throw e;
+    }
+    HSAuditLogger.logSuccess(user.getShortUserName(), "refreshLoadedJobCache",
+        HISTORY_ADMIN_SERVER);
+  }
+
   @Override
   public void refreshLogRetentionSettings() throws IOException {
     UserGroupInformation user = checkAcls("refreshLogRetentionSettings");

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/main/proto/HSAdminRefreshProtocol.proto

@@ -33,6 +33,18 @@ message RefreshAdminAclsRequestProto {
 message RefreshAdminAclsResponseProto {
 }
 
+/**
+ *  refresh loaded job cache request.
+ */
+message RefreshLoadedJobCacheRequestProto {
+}
+
+/**
+ * Response for refresh loaded job cache.
+ */
+message RefreshLoadedJobCacheResponseProto {
+}
+
 /**
  *  refresh job retention settings request.
  */
@@ -66,6 +78,12 @@ service HSAdminRefreshProtocolService {
    */
   rpc refreshAdminAcls(RefreshAdminAclsRequestProto)
       returns(RefreshAdminAclsResponseProto);
+  
+  /**
+   * Refresh loaded job cache
+   */
+  rpc refreshLoadedJobCache(RefreshLoadedJobCacheRequestProto)
+      returns(RefreshLoadedJobCacheResponseProto);
       
   /**
    * Refresh job retention.

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/test/java/org/apache/hadoop/mapreduce/v2/hs/TestJobHistory.java

@@ -18,6 +18,8 @@
 
 package org.apache.hadoop.mapreduce.v2.hs;
 
+import java.util.Map;
+
 import java.io.IOException;
 import java.util.LinkedList;
 import java.util.List;
@@ -27,8 +29,10 @@ import org.apache.hadoop.fs.FileContext;
 import org.apache.hadoop.fs.FileStatus;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.mapreduce.v2.api.records.JobId;
+import org.apache.hadoop.mapreduce.v2.api.records.JobState;
 import org.apache.hadoop.mapreduce.v2.hs.HistoryFileManager.HistoryFileInfo;
 import org.apache.hadoop.mapreduce.v2.hs.HistoryFileManager.JobListCache;
+import org.apache.hadoop.mapreduce.v2.hs.webapp.dao.JobsInfo;
 import org.apache.hadoop.mapreduce.v2.jobhistory.JHAdminConfig;
 import org.apache.hadoop.mapreduce.v2.jobhistory.JobHistoryUtils;
 import org.junit.After;
@@ -36,11 +40,76 @@ import org.junit.Test;
 
 import static org.junit.Assert.assertEquals;
 import static org.mockito.Mockito.*;
+import org.apache.hadoop.mapreduce.v2.app.job.Job;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
 
 public class TestJobHistory {
 
   JobHistory jobHistory = null;
 
+  @Test
+  public void testRefreshLoadedJobCache() throws Exception {
+    HistoryFileManager historyManager = mock(HistoryFileManager.class);
+    jobHistory = spy(new JobHistory());
+    doReturn(historyManager).when(jobHistory).createHistoryFileManager();
+
+    Configuration conf = new Configuration();
+    // Set the cache size to 2
+    conf.set(JHAdminConfig.MR_HISTORY_LOADED_JOB_CACHE_SIZE, "2");
+    jobHistory.init(conf);
+    jobHistory.start();
+
+    CachedHistoryStorage storage = spy((CachedHistoryStorage) jobHistory
+        .getHistoryStorage());
+
+    Job[] jobs = new Job[3];
+    JobId[] jobIds = new JobId[3];
+
+    for (int i = 0; i < 3; i++) {
+      jobs[i] = mock(Job.class);
+      jobIds[i] = mock(JobId.class);
+      when(jobs[i].getID()).thenReturn(jobIds[i]);
+    }
+
+    HistoryFileInfo fileInfo = mock(HistoryFileInfo.class);
+    when(historyManager.getFileInfo(any(JobId.class))).thenReturn(fileInfo);
+    when(fileInfo.loadJob()).thenReturn(jobs[0]).thenReturn(jobs[1])
+        .thenReturn(jobs[2]);
+
+    // getFullJob will put the job in the cache if it isn't there
+    for (int i = 0; i < 3; i++) {
+      storage.getFullJob(jobs[i].getID());
+    }
+
+    Map<JobId, Job> jobCache = storage.getLoadedJobCache();
+    // job0 should have been purged since cache size is 2
+    assertFalse(jobCache.containsKey(jobs[0].getID()));
+    assertTrue(jobCache.containsKey(jobs[1].getID())
+        && jobCache.containsKey(jobs[2].getID()));
+
+    // Setting cache size to 3
+    conf.set(JHAdminConfig.MR_HISTORY_LOADED_JOB_CACHE_SIZE, "3");
+    doReturn(conf).when(storage).createConf();
+
+    when(fileInfo.loadJob()).thenReturn(jobs[0]).thenReturn(jobs[1])
+        .thenReturn(jobs[2]);
+
+    jobHistory.refreshLoadedJobCache();
+
+    for (int i = 0; i < 3; i++) {
+      storage.getFullJob(jobs[i].getID());
+    }
+
+    jobCache = storage.getLoadedJobCache();
+
+    // All three jobs should be in cache since its size is now 3
+    for (int i = 0; i < 3; i++) {
+      assertTrue(jobCache.containsKey(jobs[i].getID()));
+    }
+  }
+
   @Test
   public void testRefreshJobRetentionSettings() throws IOException,
       InterruptedException {
@@ -147,6 +216,54 @@ public class TestJobHistory {
     verify(fileInfo, timeout(20000).times(2)).delete();
   }
 
+  @Test
+  public void testRefreshLoadedJobCacheUnSupportedOperation() {
+    jobHistory = spy(new JobHistory());
+    HistoryStorage storage = new HistoryStorage() {
+
+      @Override
+      public void setHistoryFileManager(HistoryFileManager hsManager) {
+        // TODO Auto-generated method stub
+
+      }
+
+      @Override
+      public JobsInfo getPartialJobs(Long offset, Long count, String user,
+          String queue, Long sBegin, Long sEnd, Long fBegin, Long fEnd,
+          JobState jobState) {
+        // TODO Auto-generated method stub
+        return null;
+      }
+
+      @Override
+      public Job getFullJob(JobId jobId) {
+        // TODO Auto-generated method stub
+        return null;
+      }
+
+      @Override
+      public Map<JobId, Job> getAllPartialJobs() {
+        // TODO Auto-generated method stub
+        return null;
+      }
+    };
+
+    doReturn(storage).when(jobHistory).createHistoryStorage();
+
+    jobHistory.init(new Configuration());
+
+    jobHistory.start();
+
+    Throwable th = null;
+    try {
+      jobHistory.refreshLoadedJobCache();
+    } catch (Exception e) {
+      th = e;
+    }
+
+    assertTrue(th instanceof UnsupportedOperationException);
+  }
+  
   @After
   public void cleanUp() {
     if (jobHistory != null) {

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/test/java/org/apache/hadoop/mapreduce/v2/hs/server/TestHSAdminServer.java

@@ -241,6 +241,14 @@ public class TestHSAdminServer {
     assertTrue(th instanceof RemoteException);
   }
 
+  @Test
+  public void testRefreshLoadedJobCache() throws Exception {
+    String[] args = new String[1];
+    args[0] = "-refreshLoadedJobCache";
+    hsAdminClient.run(args);
+    verify(jobHistoryService).refreshLoadedJobCache();
+  }
+  
   @Test
   public void testRefreshLogRetentionSettings() throws Exception {
     String[] args = new String[1];