HBASE-5715 Revert 'Instant schema alter' for now, HBASE-4213

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1310012 13f79535-47bb-0310-9956-ffa450edef68

src/main/java/org/apache/hadoop/hbase/LocalHBaseCluster.java

@@ -309,12 +309,14 @@ public class LocalHBaseCluster {
    */
   public HMaster getActiveMaster() {
     for (JVMClusterUtil.MasterThread mt : masterThreads) {
+      if (mt.getMaster().isActiveMaster()) {
         // Ensure that the current active master is not stopped.
         // We don't want to return a stopping master as an active master.
         if (mt.getMaster().isActiveMaster()  && !mt.getMaster().isStopped()) {
           return mt.getMaster();
         }
       }
+    }
     return null;
   }
 

src/main/java/org/apache/hadoop/hbase/executor/EventHandler.java

@@ -144,12 +144,13 @@ public abstract class EventHandler implements Runnable, Comparable<Runnable> {
      * Constructor
      */
     EventType(int value) {}
-    public boolean isSchemaChangeEvent() {
+    public boolean isOnlineSchemaChangeSupported() {
       return (
         this.equals(EventType.C_M_ADD_FAMILY) ||
         this.equals(EventType.C_M_DELETE_FAMILY) ||
         this.equals(EventType.C_M_MODIFY_FAMILY) ||
-          this.equals(EventType.C_M_MODIFY_TABLE));
+        this.equals(EventType.C_M_MODIFY_TABLE)
+      );
     }
   }
 

src/main/java/org/apache/hadoop/hbase/ipc/HMasterInterface.java

@@ -266,12 +266,4 @@ public interface HMasterInterface extends VersionedProtocol {
    * @return array of HTableDescriptor
    */
   public HTableDescriptor[] getHTableDescriptors(List<String> tableNames);
-
-  /**
-   * Returns the current running status of load balancer.
-   * @return True if LoadBalancer is running now else False.
-   */
-  public boolean isLoadBalancerRunning();
-
-
 }

src/main/java/org/apache/hadoop/hbase/master/AssignmentManager.java

@@ -304,7 +304,7 @@ public class AssignmentManager extends ZooKeeperListener {
     List <HRegionInfo> hris =
       MetaReader.getTableRegions(this.master.getCatalogTracker(), tableName);
     Integer pending = 0;
-    for(HRegionInfo hri : hris) {
+    for (HRegionInfo hri : hris) {
       String name = hri.getEncodedName();
       if (regionsToReopen.containsKey(name) || regionsInTransition.containsKey(name)) {
         pending++;

src/main/java/org/apache/hadoop/hbase/master/HMaster.java

@@ -71,7 +71,6 @@ import org.apache.hadoop.hbase.client.MetaScanner;
 import org.apache.hadoop.hbase.client.MetaScanner.MetaScannerVisitor;
 import org.apache.hadoop.hbase.client.Result;
 import org.apache.hadoop.hbase.coprocessor.CoprocessorHost;
-import org.apache.hadoop.hbase.executor.EventHandler;
 import org.apache.hadoop.hbase.executor.ExecutorService;
 import org.apache.hadoop.hbase.executor.ExecutorService.ExecutorType;
 import org.apache.hadoop.hbase.ipc.HBaseRPC;
@@ -91,6 +90,7 @@ import org.apache.hadoop.hbase.master.handler.TableDeleteFamilyHandler;
 import org.apache.hadoop.hbase.master.handler.TableEventHandler;
 import org.apache.hadoop.hbase.master.handler.TableModifyFamilyHandler;
 import org.apache.hadoop.hbase.master.metrics.MasterMetrics;
+import org.apache.hadoop.hbase.master.RegionPlan;
 import org.apache.hadoop.hbase.monitoring.MemoryBoundedLogMessageBuffer;
 import org.apache.hadoop.hbase.monitoring.MonitoredTask;
 import org.apache.hadoop.hbase.monitoring.TaskMonitor;
@@ -107,7 +107,6 @@ import org.apache.hadoop.hbase.util.VersionInfo;
 import org.apache.hadoop.hbase.zookeeper.ClusterId;
 import org.apache.hadoop.hbase.zookeeper.ClusterStatusTracker;
 import org.apache.hadoop.hbase.zookeeper.DrainingServerTracker;
-import org.apache.hadoop.hbase.zookeeper.MasterSchemaChangeTracker;
 import org.apache.hadoop.hbase.zookeeper.RegionServerTracker;
 import org.apache.hadoop.hbase.zookeeper.ZKUtil;
 import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
@@ -185,9 +184,6 @@ Server {
   // Cluster status zk tracker and local setter
   private ClusterStatusTracker clusterStatusTracker;
   
-  // Schema change tracker
-  private MasterSchemaChangeTracker schemaChangeTracker;
-
   // buffer for "fatal error" notices from region servers
   // in the cluster. This is only used for assisting
   // operations/debugging.
@@ -215,18 +211,12 @@ Server {
 
   private CatalogJanitor catalogJanitorChore;
   private LogCleaner logCleaner;
-  private Thread schemaJanitorChore;
 
   private MasterCoprocessorHost cpHost;
   private final ServerName serverName;
 
   private TableDescriptors tableDescriptors;
 
-  // Whether or not schema alter changes go through ZK or not.
-  private boolean supportInstantSchemaChanges = false;
-
-  private volatile boolean loadBalancerRunning = false;
-
   // Time stamps for when a hmaster was started and when it became active
   private long masterStartTime;
   private long masterActiveTime;
@@ -300,18 +290,6 @@ Server {
     this.zooKeeper = new ZooKeeperWatcher(conf, MASTER + ":" + isa.getPort(), this, true);
     this.rpcServer.startThreads();
     this.metrics = new MasterMetrics(getServerName().toString());
-    this.supportInstantSchemaChanges = getSupportInstantSchemaChanges(conf);
-  }
-
-  /**
-   * Get whether instant schema change is on or not.
-   * @param c
-   * @return True if instant schema enabled.
-   */
-  private boolean getSupportInstantSchemaChanges(final Configuration c) {
-    boolean b = c.getBoolean("hbase.instant.schema.alter.enabled", false);
-    LOG.debug("Instant schema change enabled=" + b + ".");
-    return b;
   }
 
   /**
@@ -451,12 +429,6 @@ Server {
     boolean wasUp = this.clusterStatusTracker.isClusterUp();
     if (!wasUp) this.clusterStatusTracker.setClusterUp();
 
-    // initialize schema change tracker
-    this.schemaChangeTracker = new MasterSchemaChangeTracker(getZooKeeper(),
-        this, this,
-        conf.getInt("hbase.instant.schema.alter.timeout", 60000));
-    this.schemaChangeTracker.start();
-
     LOG.info("Server active/primary master; " + this.serverName +
         ", sessionid=0x" +
         Long.toHexString(this.zooKeeper.getRecoverableZooKeeper().getSessionId()) +
@@ -596,9 +568,6 @@ Server {
     this.catalogJanitorChore = new CatalogJanitor(this, this);
     Threads.setDaemonThreadRunning(catalogJanitorChore.getThread());
 
-    // Schema janitor chore.
-    this.schemaJanitorChore = getAndStartSchemaJanitorChore(this);
-
     registerMBean();
 
     status.markComplete("Initialization successful");
@@ -811,15 +780,6 @@ Server {
     return this.tableDescriptors;
   }
 
-  @Override
-  public MasterSchemaChangeTracker getSchemaChangeTracker() {
-    return this.schemaChangeTracker;
-  }
-
-  public RegionServerTracker getRegionServerTracker() {
-    return this.regionServerTracker;
-  }
-
   /** @return InfoServer object. Maybe null.*/
   public InfoServer getInfoServer() {
     return this.infoServer;
@@ -931,28 +891,7 @@ Server {
     if (this.executorService != null) this.executorService.shutdown();
   }
 
-  /**
+  private static Thread getAndStartBalancerChore(final HMaster master) {
-   * Start the schema janitor. This Janitor will periodically sweep the failed/expired schema
-   * changes.
-   * @param master
-   * @return
-   */
-  private Thread getAndStartSchemaJanitorChore(final HMaster master) {
-    String name = master.getServerName() + "-SchemaJanitorChore";
-    int schemaJanitorPeriod =
-      master.getConfiguration().getInt("hbase.instant.schema.janitor.period", 120000);
-    // Start up the schema janitor chore
-    Chore chore = new Chore(name, schemaJanitorPeriod, master) {
-      @Override
-      protected void chore() {
-        master.getSchemaChangeTracker().handleFailedOrExpiredSchemaChanges();
-      }
-    };
-    return Threads.setDaemonThreadRunning(chore.getThread());
-  }
-
-
-  private Thread getAndStartBalancerChore(final HMaster master) {
     String name = master.getServerName() + "-BalancerChore";
     int balancerPeriod =
       master.getConfiguration().getInt("hbase.balancer.period", 300000);
@@ -973,10 +912,6 @@ Server {
     if (this.catalogJanitorChore != null) {
       this.catalogJanitorChore.interrupt();
     }
-    if (this.schemaJanitorChore != null) {
-      this.schemaJanitorChore.interrupt();
-    }
-
   }
 
   @Override
@@ -1058,15 +993,6 @@ Server {
     return balancerCutoffTime;
   }
 
-
-  /**
-   * Check whether the Load Balancer is currently running.
-   * @return true if the Load balancer is currently running.
-   */
-  public boolean isLoadBalancerRunning() {
-    return loadBalancerRunning;
-  }
-
   @Override
   public boolean balance() {
     // If balance not true, don't run balancer.
@@ -1074,13 +1000,8 @@ Server {
     // Do this call outside of synchronized block.
     int maximumBalanceTime = getBalancerCutoffTime();
     long cutoffTime = System.currentTimeMillis() + maximumBalanceTime;
-    boolean balancerRan = false;
+    boolean balancerRan;
     synchronized (this.balancer) {
-      if (loadBalancerRunning) {
-        LOG.debug("Load balancer is currently running. Skipping the current execution.");
-        return false;
-      }
-
       // Only allow one balance run at at time.
       if (this.assignmentManager.isRegionsInTransition()) {
         LOG.debug("Not running balancer because " +
@@ -1095,12 +1016,7 @@ Server {
           this.serverManager.getDeadServers());
         return false;
       }
-      if (schemaChangeTracker.isSchemaChangeInProgress()) {
+
-        LOG.debug("Schema change operation is in progress. Waiting for " +
-        "it to complete before running the load balancer.");
-        return false;
-      }
-      loadBalancerRunning = true;
       if (this.cpHost != null) {
         try {
           if (this.cpHost.preBalance()) {
@@ -1148,7 +1064,6 @@ Server {
           LOG.error("Error invoking master coprocessor postBalance()", ioe);
         }
       }
-      loadBalancerRunning = false;
     }
     return balancerRan;
   }
@@ -1298,9 +1213,7 @@ Server {
     if (cpHost != null) {
       cpHost.preDeleteTable(tableName);
     }
-    this.executorService.submit(new DeleteTableHandler(tableName, this, this, this,
+    this.executorService.submit(new DeleteTableHandler(tableName, this, this));
-        supportInstantSchemaChanges));
-
     if (cpHost != null) {
       cpHost.postDeleteTable(tableName);
     }
@@ -1312,6 +1225,7 @@ Server {
    * @return Pair indicating the number of regions updated Pair.getFirst is the
    *         regions that are yet to be updated Pair.getSecond is the total number
    *         of regions of the table
+   * @throws IOException 
    */
   public Pair<Integer, Integer> getAlterStatus(byte[] tableName)
   throws IOException {
@@ -1319,44 +1233,9 @@ Server {
     // may overlap with other table operations or the table operation may
     // have completed before querying this API. We need to refactor to a
     // transaction system in the future to avoid these ambiguities.
-    if (supportInstantSchemaChanges) {
-      return getAlterStatusFromSchemaChangeTracker(tableName);
-    }
     return this.assignmentManager.getReopenStatus(tableName);
   }
 
-  /**
-   * Used by the client to identify if all regions have the schema updates
-   *
-   * @param tableName
-   * @return Pair indicating the status of the alter command
-   * @throws IOException
-   */
-  private Pair<Integer, Integer> getAlterStatusFromSchemaChangeTracker(byte[] tableName)
-      throws IOException {
-    MasterSchemaChangeTracker.MasterAlterStatus alterStatus = null;
-    try {
-      alterStatus =
-          this.schemaChangeTracker.getMasterAlterStatus(Bytes.toString(tableName));
-    } catch (KeeperException ke) {
-      LOG.error("KeeperException while getting schema alter status for table = "
-      + Bytes.toString(tableName), ke);
-    }
-    if (alterStatus != null) {
-      LOG.debug("Getting AlterStatus from SchemaChangeTracker for table = "
-          + Bytes.toString(tableName) + " Alter Status = "
-          + alterStatus.toString());
-      return new Pair<Integer, Integer>(alterStatus.getNumberOfRegionsProcessed(),
-          alterStatus.getNumberOfRegionsToProcess());
-    } else {
-      LOG.debug("MasterAlterStatus is NULL for table = "
-          + Bytes.toString(tableName));
-      // should we throw IOException here as it makes more sense?
-      return new Pair<Integer, Integer>(0,0);
-    }
-  }
-
-
   public void addColumn(byte [] tableName, HColumnDescriptor column)
   throws IOException {
     checkInitialized();
@@ -1365,8 +1244,7 @@ Server {
         return;
       }
     }
-    new TableAddFamilyHandler(tableName, column, this, this,
+    new TableAddFamilyHandler(tableName, column, this, this).process();
-        this, supportInstantSchemaChanges).process();
     if (cpHost != null) {
       cpHost.postAddColumn(tableName, column);
     }
@@ -1380,8 +1258,7 @@ Server {
         return;
       }
     }
-    new TableModifyFamilyHandler(tableName, descriptor, this, this,
+    new TableModifyFamilyHandler(tableName, descriptor, this, this).process();
-        this, supportInstantSchemaChanges).process();
     if (cpHost != null) {
       cpHost.postModifyColumn(tableName, descriptor);
     }
@@ -1395,8 +1272,7 @@ Server {
         return;
       }
     }
-    new TableDeleteFamilyHandler(tableName, c, this, this,
+    new TableDeleteFamilyHandler(tableName, c, this, this).process();
-        this, supportInstantSchemaChanges).process();
     if (cpHost != null) {
       cpHost.postDeleteColumn(tableName, c);
     }
@@ -1470,8 +1346,7 @@ Server {
     if (cpHost != null) {
       cpHost.preModifyTable(tableName, htd);
     }
-    TableEventHandler tblHandle = new ModifyTableHandler(tableName, htd, this,
+    TableEventHandler tblHandle = new ModifyTableHandler(tableName, htd, this, this);
-        this, this, supportInstantSchemaChanges);
     this.executorService.submit(tblHandle);
     tblHandle.waitForPersist();
 
@@ -1480,26 +1355,8 @@ Server {
     }
   }
 
-  private boolean isOnlineSchemaChangeAllowed() {
-    return conf.getBoolean(
-        "hbase.online.schema.update.enable", false);
-  }
-  
   @Override
-  public void checkTableModifiable(final byte [] tableName,
+  public void checkTableModifiable(final byte [] tableName)
-                                   EventHandler.EventType eventType)
-  throws IOException {
-    preCheckTableModifiable(tableName);
-    if (!eventType.isSchemaChangeEvent() ||
-        !isOnlineSchemaChangeAllowed()) {
-      if (!getAssignmentManager().getZKTable().
-          isDisabledTable(Bytes.toString(tableName))) {
-        throw new TableNotDisabledException(tableName);
-      }
-    }
-  }
-
-  private void preCheckTableModifiable(final byte[] tableName)
   throws IOException {
     String tableNameStr = Bytes.toString(tableName);
     if (isCatalogTable(tableName)) {
@@ -1508,6 +1365,10 @@ Server {
     if (!MetaReader.tableExists(getCatalogTracker(), tableNameStr)) {
       throw new TableNotFoundException(tableNameStr);
     }
+    if (!getAssignmentManager().getZKTable().
+        isDisabledTable(Bytes.toString(tableName))) {
+      throw new TableNotDisabledException(tableName);
+    }
   }
 
   public void clearFromTransition(HRegionInfo hri) {

src/main/java/org/apache/hadoop/hbase/master/MasterFileSystem.java

@@ -514,7 +514,7 @@ public class MasterFileSystem {
    */
   public HTableDescriptor addColumn(byte[] tableName, HColumnDescriptor hcd)
       throws IOException {
-    LOG.debug("AddColumn. Table = " + Bytes.toString(tableName) + " HCD = " +
+    LOG.info("AddColumn. Table = " + Bytes.toString(tableName) + " HCD = " +
       hcd.toString());
     HTableDescriptor htd = this.services.getTableDescriptors().get(tableName);
     if (htd == null) {

src/main/java/org/apache/hadoop/hbase/master/MasterServices.java

@@ -27,7 +27,6 @@ import org.apache.hadoop.hbase.Server;
 import org.apache.hadoop.hbase.TableDescriptors;
 import org.apache.hadoop.hbase.executor.EventHandler;
 import org.apache.hadoop.hbase.executor.ExecutorService;
-import org.apache.hadoop.hbase.zookeeper.MasterSchemaChangeTracker;
 import org.apache.hadoop.hbase.zookeeper.RegionServerTracker;
 
 /**
@@ -56,15 +55,12 @@ public interface MasterServices extends Server {
   public ExecutorService getExecutorService();
 
   /**
-   * Check table modifiable. i.e not ROOT or META and offlined for all commands except
+   * Check table is modifiable; i.e. exists and is offline.
-   * alter commands
+   * @param tableName Name of table to check.
-   * @param tableName
+   * @throws TableNotDisabledException
-   * @param eventType
+   * @throws TableNotFoundException 
-   * @throws IOException
    */
-  public void checkTableModifiable(final byte [] tableName,
+  public void checkTableModifiable(final byte [] tableName) throws IOException;
-                                   EventHandler.EventType eventType)
-      throws IOException;
 
   /**
    * Create a table using the given table definition.
@@ -80,21 +76,8 @@ public interface MasterServices extends Server {
    */
   public TableDescriptors getTableDescriptors();
 
-  /**
-   * Get Master Schema change tracker
-   * @return
-   */
-  public MasterSchemaChangeTracker getSchemaChangeTracker();
-
-  /**
-   * Return the Region server tracker.
-   * @return RegionServerTracker
-   */
-  public RegionServerTracker getRegionServerTracker();
-
   /**
    * @return true if master enables ServerShutdownHandler;
    */
   public boolean isServerShutdownHandlerEnabled();
-
 }

src/main/java/org/apache/hadoop/hbase/master/ServerManager.java

@@ -345,15 +345,6 @@ public class ServerManager {
     }
   }
 
-  /**
-   * Exclude a RS from any pending schema change process.
-   * @param serverName
-   */
-  private void excludeRegionServerFromSchemaChanges(final ServerName serverName) {
-    this.services.getSchemaChangeTracker()
-        .excludeRegionServerForSchemaChanges(serverName.getServerName());
-  }
-
   /*
    * Expire the passed server.  Add it to list of deadservers and queue a
    * shutdown processing.
@@ -365,7 +356,6 @@ public class ServerManager {
       this.deadNotExpiredServers.add(serverName);
       return;
     }
-    excludeRegionServerFromSchemaChanges(serverName);
     if (!this.onlineServers.containsKey(serverName)) {
       LOG.warn("Received expiration of " + serverName +
         " but server is not currently online");

src/main/java/org/apache/hadoop/hbase/master/handler/DeleteTableHandler.java

@@ -28,7 +28,6 @@ import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.hbase.HRegionInfo;
 import org.apache.hadoop.hbase.Server;
 import org.apache.hadoop.hbase.catalog.MetaEditor;
-import org.apache.hadoop.hbase.ipc.HMasterInterface;
 import org.apache.hadoop.hbase.master.AssignmentManager;
 import org.apache.hadoop.hbase.master.MasterServices;
 import org.apache.hadoop.hbase.util.Bytes;
@@ -40,11 +39,9 @@ public class DeleteTableHandler extends TableEventHandler {
   private static final Log LOG = LogFactory.getLog(DeleteTableHandler.class);
 
   public DeleteTableHandler(byte [] tableName, Server server,
-      final MasterServices masterServices, HMasterInterface masterInterface,
+      final MasterServices masterServices)
-      boolean instantChange)
   throws IOException {
-    super(EventType.C_M_DELETE_TABLE, tableName, server, masterServices,
+    super(EventType.C_M_DELETE_TABLE, tableName, server, masterServices);
-        masterInterface, instantChange);
     // The next call fails if no such table.
     getTableDescriptor();
   }

src/main/java/org/apache/hadoop/hbase/master/handler/ModifyTableHandler.java

@@ -26,7 +26,6 @@ import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.hbase.HRegionInfo;
 import org.apache.hadoop.hbase.HTableDescriptor;
 import org.apache.hadoop.hbase.Server;
-import org.apache.hadoop.hbase.ipc.HMasterInterface;
 import org.apache.hadoop.hbase.master.MasterServices;
 
 @InterfaceAudience.Private
@@ -35,11 +34,9 @@ public class ModifyTableHandler extends TableEventHandler {
 
   public ModifyTableHandler(final byte [] tableName,
       final HTableDescriptor htd, final Server server,
-      final MasterServices masterServices, final HMasterInterface masterInterface,
+      final MasterServices masterServices)
-      boolean instantModify)
   throws IOException {
-    super(EventType.C_M_MODIFY_TABLE, tableName, server, masterServices,
+    super(EventType.C_M_MODIFY_TABLE, tableName, server, masterServices);
-        masterInterface, instantModify);
     // Check table exists.
     getTableDescriptor();
     // This is the new schema we are going to write out as this modification.

src/main/java/org/apache/hadoop/hbase/master/handler/TableAddFamilyHandler.java

@@ -28,7 +28,6 @@ import org.apache.hadoop.hbase.HRegionInfo;
 import org.apache.hadoop.hbase.HTableDescriptor;
 import org.apache.hadoop.hbase.InvalidFamilyOperationException;
 import org.apache.hadoop.hbase.Server;
-import org.apache.hadoop.hbase.ipc.HMasterInterface;
 import org.apache.hadoop.hbase.master.MasterServices;
 
 /**
@@ -40,10 +39,8 @@ public class TableAddFamilyHandler extends TableEventHandler {
   private final HColumnDescriptor familyDesc;
 
   public TableAddFamilyHandler(byte[] tableName, HColumnDescriptor familyDesc,
-      Server server, final MasterServices masterServices,
+      Server server, final MasterServices masterServices) throws IOException {
-      HMasterInterface masterInterface, boolean instantChange) throws IOException {
+    super(EventType.C_M_ADD_FAMILY, tableName, server, masterServices);
-    super(EventType.C_M_ADD_FAMILY, tableName, server, masterServices,
-        masterInterface, instantChange);
     HTableDescriptor htd = getTableDescriptor();
     if (htd.hasFamily(familyDesc.getName())) {
       throw new InvalidFamilyOperationException("Family '" +

src/main/java/org/apache/hadoop/hbase/master/handler/TableDeleteFamilyHandler.java

@@ -26,7 +26,6 @@ import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.hbase.HRegionInfo;
 import org.apache.hadoop.hbase.HTableDescriptor;
 import org.apache.hadoop.hbase.Server;
-import org.apache.hadoop.hbase.ipc.HMasterInterface;
 import org.apache.hadoop.hbase.master.MasterServices;
 import org.apache.hadoop.hbase.util.Bytes;
 
@@ -39,10 +38,8 @@ public class TableDeleteFamilyHandler extends TableEventHandler {
   private final byte [] familyName;
 
   public TableDeleteFamilyHandler(byte[] tableName, byte [] familyName,
-      Server server, final MasterServices masterServices,
+      Server server, final MasterServices masterServices) throws IOException {
-      HMasterInterface masterInterface, boolean instantChange) throws IOException {
+    super(EventType.C_M_ADD_FAMILY, tableName, server, masterServices);
-    super(EventType.C_M_ADD_FAMILY, tableName, server, masterServices,
-        masterInterface, instantChange);
     HTableDescriptor htd = getTableDescriptor();
     this.familyName = hasColumnFamily(htd, familyName);
   }

src/main/java/org/apache/hadoop/hbase/master/handler/TableEventHandler.java

@@ -37,19 +37,13 @@ import org.apache.hadoop.hbase.InvalidFamilyOperationException;
 import org.apache.hadoop.hbase.Server;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.TableExistsException;
+import org.apache.hadoop.hbase.TableNotDisabledException;
 import org.apache.hadoop.hbase.catalog.MetaReader;
 import org.apache.hadoop.hbase.client.HTable;
 import org.apache.hadoop.hbase.executor.EventHandler;
-import org.apache.hadoop.hbase.ipc.HMasterInterface;
 import org.apache.hadoop.hbase.master.BulkReOpen;
 import org.apache.hadoop.hbase.master.MasterServices;
-import org.apache.hadoop.hbase.monitoring.MonitoredTask;
-import org.apache.hadoop.hbase.monitoring.TaskMonitor;
 import org.apache.hadoop.hbase.util.Bytes;
-import org.apache.hadoop.hbase.zookeeper.MasterSchemaChangeTracker;
-import org.apache.hadoop.hbase.zookeeper.ZKAssign;
-import org.apache.hadoop.hbase.zookeeper.ZKUtil;
-import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
 import org.apache.zookeeper.KeeperException;
 
 import com.google.common.collect.Lists;
@@ -66,23 +60,33 @@ import com.google.common.collect.Maps;
 public abstract class TableEventHandler extends EventHandler {
   private static final Log LOG = LogFactory.getLog(TableEventHandler.class);
   protected final MasterServices masterServices;
-  protected HMasterInterface master = null;
   protected final byte [] tableName;
   protected final String tableNameStr;
-  protected boolean instantAction = false;
   protected boolean persistedToZk = false;
 
   public TableEventHandler(EventType eventType, byte [] tableName, Server server,
-      MasterServices masterServices, HMasterInterface masterInterface,
+      MasterServices masterServices)
-      boolean instantSchemaChange)
   throws IOException {
     super(server, eventType);
     this.masterServices = masterServices;
     this.tableName = tableName;
-    this.masterServices.checkTableModifiable(tableName, eventType);
+    try {
+      this.masterServices.checkTableModifiable(tableName);
+    } catch (TableNotDisabledException ex)  {
+      if (isOnlineSchemaChangeAllowed()
+          && eventType.isOnlineSchemaChangeSupported()) {
+        LOG.debug("Ignoring table not disabled exception " +
+            "for supporting online schema changes.");
+      }	else {
+        throw ex;
+      }
+    }
     this.tableNameStr = Bytes.toString(this.tableName);
-    this.instantAction = instantSchemaChange;
+  }
-    this.master = masterInterface;
+
+ private boolean isOnlineSchemaChangeAllowed() {
+   return this.server.getConfiguration().getBoolean(
+     "hbase.online.schema.update.enable", false);
  }
 
   @Override
@@ -94,7 +98,16 @@ public abstract class TableEventHandler extends EventHandler {
         MetaReader.getTableRegions(this.server.getCatalogTracker(),
           tableName);
       handleTableOperation(hris);
-      handleSchemaChanges(hris);
+      if (eventType.isOnlineSchemaChangeSupported() && this.masterServices.
+          getAssignmentManager().getZKTable().
+          isEnabledTable(Bytes.toString(tableName))) {
+        if (reOpenAllRegions(hris)) {
+          LOG.info("Completed table operation " + eventType + " on table " +
+              Bytes.toString(tableName));
+        } else {
+          LOG.warn("Error on reopening the regions");
+        }
+      }
     } catch (IOException e) {
       LOG.error("Error manipulating table " + Bytes.toString(tableName), e);
     } catch (KeeperException e) {
@@ -105,48 +118,13 @@ public abstract class TableEventHandler extends EventHandler {
     }
   }
 
-  private void handleSchemaChanges(List<HRegionInfo> regions)
-      throws IOException {
-    if (instantAction && regions != null && !regions.isEmpty()) {
-      handleInstantSchemaChanges(regions);
-    } else {
-      handleRegularSchemaChanges(regions);
-    }
-  }
-
-
-  /**
-   * Perform schema changes only if the table is in enabled state.
-   * @return
-   */
-  private boolean canPerformSchemaChange() {
-    return (eventType.isSchemaChangeEvent() && this.masterServices.
-        getAssignmentManager().getZKTable().
-        isEnabledTable(Bytes.toString(tableName)));
-  }
-
-  private void handleRegularSchemaChanges(List<HRegionInfo> regions)
-      throws IOException {
-    if (canPerformSchemaChange()) {
-      this.masterServices.getAssignmentManager().setRegionsToReopen(regions);
-      setPersist();
-      if (reOpenAllRegions(regions)) {
-        LOG.info("Completed table operation " + eventType + " on table " +
-            Bytes.toString(tableName));
-      } else {
-        LOG.warn("Error on reopening the regions");
-      }
-    }
-  }
-
   public boolean reOpenAllRegions(List<HRegionInfo> regions) throws IOException {
     boolean done = false;
     LOG.info("Bucketing regions by region server...");
     HTable table = new HTable(masterServices.getConfiguration(), tableName);
     TreeMap<ServerName, List<HRegionInfo>> serverToRegions = Maps
         .newTreeMap();
-    NavigableMap<HRegionInfo, ServerName> hriHserverMapping
+    NavigableMap<HRegionInfo, ServerName> hriHserverMapping = table.getRegionLocations();
-        = table.getRegionLocations();
     List<HRegionInfo> reRegions = new ArrayList<HRegionInfo>();
     for (HRegionInfo hri : regions) {
       ServerName rsLocation = hriHserverMapping.get(hri);
@@ -188,32 +166,6 @@ public abstract class TableEventHandler extends EventHandler {
     return done;
   }
 
-  /**
-   * Check whether any of the regions from the list of regions is undergoing a split.
-   * We simply check whether there is a unassigned node for any of the region and if so
-   * we return as true.
-   * @param regionInfos
-   * @return
-   */
-  private boolean isSplitInProgress(List<HRegionInfo> regionInfos) {
-    for (HRegionInfo hri : regionInfos) {
-      ZooKeeperWatcher zkw = this.masterServices.getZooKeeper();
-      String node = ZKAssign.getNodeName(zkw, hri.getEncodedName());
-      try {
-        if (ZKUtil.checkExists(zkw, node) != -1) {
-          LOG.debug("Region " + hri.getRegionNameAsString() + " is unassigned. Assuming" +
-          " that it is undergoing a split");
-          return true;
-        }
-      } catch (KeeperException ke) {
-        LOG.debug("KeeperException while determining splits in progress.", ke);
-        // Assume no splits happening?
-        return false;
-      }
-    }
-    return false;
-  }
-
   /**
    * Table modifications are processed asynchronously, but provide an API for
    * you to query their status.
@@ -238,65 +190,6 @@ public abstract class TableEventHandler extends EventHandler {
     }
   }
 
-  /**
-   * Wait for region split transaction in progress (if any)
-   * @param regions
-   * @param status
-   */
-  private void waitForInflightSplit(List<HRegionInfo> regions, MonitoredTask status) {
-    while (isSplitInProgress(regions)) {
-      try {
-        status.setStatus("Alter Schema is waiting for split region to complete.");
-        Thread.sleep(100);
-      } catch (InterruptedException e) {
-        Thread.currentThread().interrupt();
-      }
-    }
-  }
-
-  protected void handleInstantSchemaChanges(List<HRegionInfo> regions) {
-    if (regions == null || regions.isEmpty()) {
-      LOG.debug("Region size is null or empty. Ignoring alter request.");
-      return;
-    }
-    MonitoredTask status = TaskMonitor.get().createStatus(
-        "Handling alter table request for table = " + tableNameStr);
-    if (canPerformSchemaChange()) {
-      boolean prevBalanceSwitch = false;
-      try {
-        // turn off load balancer synchronously
-        prevBalanceSwitch = master.synchronousBalanceSwitch(false);
-        waitForInflightSplit(regions, status);
-        MasterSchemaChangeTracker masterSchemaChangeTracker =
-          this.masterServices.getSchemaChangeTracker();
-        masterSchemaChangeTracker
-        .createSchemaChangeNode(Bytes.toString(tableName),
-            regions.size());
-        while(!masterSchemaChangeTracker.doesSchemaChangeNodeExists(
-            Bytes.toString(tableName))) {
-          try {
-            Thread.sleep(50);
-          } catch (InterruptedException e) {
-            Thread.currentThread().interrupt();
-          }
-        }
-        status.markComplete("Created ZK node for handling the alter table request for table = "
-            + tableNameStr);
-      } catch (KeeperException e) {
-        LOG.warn("Instant schema change failed for table " + tableNameStr, e);
-        status.setStatus("Instant schema change failed for table " + tableNameStr
-            + " Cause = " + e.getCause());
-
-      } catch (IOException ioe) {
-        LOG.warn("Instant schema change failed for table " + tableNameStr, ioe);
-        status.setStatus("Instant schema change failed for table " + tableNameStr
-            + " Cause = " + ioe.getCause());
-      } finally {
-        master.synchronousBalanceSwitch(prevBalanceSwitch);
-      }
-    }
-  }
-
   /**
    * @return Table descriptor for this table
    * @throws TableExistsException

src/main/java/org/apache/hadoop/hbase/master/handler/TableModifyFamilyHandler.java

@@ -28,7 +28,6 @@ import org.apache.hadoop.hbase.HRegionInfo;
 import org.apache.hadoop.hbase.HTableDescriptor;
 import org.apache.hadoop.hbase.InvalidFamilyOperationException;
 import org.apache.hadoop.hbase.Server;
-import org.apache.hadoop.hbase.ipc.HMasterInterface;
 import org.apache.hadoop.hbase.master.MasterServices;
 import org.apache.hadoop.hbase.util.Bytes;
 
@@ -41,10 +40,8 @@ public class TableModifyFamilyHandler extends TableEventHandler {
 
   public TableModifyFamilyHandler(byte[] tableName,
       HColumnDescriptor familyDesc, Server server,
-      final MasterServices masterServices,
+      final MasterServices masterServices) throws IOException {
-      HMasterInterface masterInterface, boolean instantChange) throws IOException {
+    super(EventType.C_M_MODIFY_FAMILY, tableName, server, masterServices);
-    super(EventType.C_M_MODIFY_FAMILY, tableName, server, masterServices,
-        masterInterface, instantChange);
     HTableDescriptor htd = getTableDescriptor();
     hasColumnFamily(htd, familyDesc.getName());
     this.familyDesc = familyDesc;

src/main/java/org/apache/hadoop/hbase/regionserver/CompactSplitThread.java

@@ -157,29 +157,12 @@ public class CompactSplitThread implements CompactionRequestor {
     return false;
   }
 
-  /**
-   * Wait for mid-flight schema alter requests. (if any). We don't want to execute a split
-   * when a schema alter is in progress as we end up in an inconsistent state.
-   * @param tableName
-   */
-  private void waitForInflightSchemaChange(String tableName) {
-    while (this.server.getSchemaChangeTracker()
-        .isSchemaChangeInProgress(tableName)) {
-      try {
-        Thread.sleep(100);
-      } catch (InterruptedException e) {
-        Thread.currentThread().interrupt();
-      }
-    }
-  }
-
   public synchronized void requestSplit(final HRegion r, byte[] midKey) {
     if (midKey == null) {
       LOG.debug("Region " + r.getRegionNameAsString() +
         " not splittable because midkey=null");
       return;
     }
-    waitForInflightSchemaChange(r.getRegionInfo().getTableNameAsString());
     try {
       this.splits.execute(new SplitRequest(r, midKey, this.server));
       if (LOG.isDebugEnabled()) {

src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java

@@ -148,7 +148,6 @@ import org.apache.hadoop.hbase.util.Threads;
 import org.apache.hadoop.hbase.util.VersionInfo;
 import org.apache.hadoop.hbase.zookeeper.ClusterStatusTracker;
 import org.apache.hadoop.hbase.zookeeper.RootRegionTracker;
-import org.apache.hadoop.hbase.zookeeper.SchemaChangeTracker;
 import org.apache.hadoop.hbase.zookeeper.ZKUtil;
 import org.apache.hadoop.hbase.zookeeper.ZooKeeperNodeTracker;
 import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
@@ -294,9 +293,6 @@ public class HRegionServer implements HRegionInterface, HBaseRPCErrorHandler,
   // Cluster Status Tracker
   private ClusterStatusTracker clusterStatusTracker;
 
-  // Schema change Tracker
-  private SchemaChangeTracker schemaChangeTracker;
-
   // Log Splitting Worker
   private SplitLogWorker splitLogWorker;
 
@@ -599,11 +595,6 @@ public class HRegionServer implements HRegionInterface, HBaseRPCErrorHandler,
     this.catalogTracker = new CatalogTracker(this.zooKeeper, this.conf,
       this, this.conf.getInt("hbase.regionserver.catalog.timeout", Integer.MAX_VALUE));
     catalogTracker.start();
-
-    // Schema change tracker
-    this.schemaChangeTracker = new SchemaChangeTracker(this.zooKeeper,
-        this, this);
-    this.schemaChangeTracker.start();
   }
 
   /**
@@ -2901,26 +2892,9 @@ public class HRegionServer implements HRegionInterface, HBaseRPCErrorHandler,
     splitRegion(regionInfo, null);
   }
 
-  /**
-   * Wait for mid-flight schema change requests. (if any)
-   * @param tableName
-   */
-  private void waitForSchemaChange(String tableName) {
-    while (schemaChangeTracker.isSchemaChangeInProgress(tableName)) {
-      try {
-        LOG.debug("Schema alter is inprogress for table = " + tableName
-            + " Waiting for alter to complete before a split");
-        Thread.sleep(100);
-      } catch (InterruptedException e) {
-        Thread.currentThread().interrupt();
-      }
-    }
-  }
-
   @Override
   public void splitRegion(HRegionInfo regionInfo, byte[] splitPoint)
       throws NotServingRegionException, IOException {
-    waitForSchemaChange(Bytes.toString(regionInfo.getTableName()));
     checkOpen();
     HRegion region = getRegion(regionInfo.getRegionName());
     region.flushcache();
@@ -3671,33 +3645,6 @@ public class HRegionServer implements HRegionInterface, HBaseRPCErrorHandler,
     return wal.rollWriter(true);
   }
 
-  /**
-  * Refresh schema changes for given region.
-  * @param hRegion HRegion to refresh
-  * @throws IOException
-  */
- public void refreshRegion(HRegion hRegion) throws IOException {
-
-   if (hRegion != null) {
-     synchronized (this.onlineRegions) {
-       HRegionInfo regionInfo = hRegion.getRegionInfo();
-       // Close the region
-       hRegion.close();
-       // Remove from online regions
-       removeFromOnlineRegions(regionInfo.getEncodedName());
-       // Get new HTD
-       HTableDescriptor htd = this.tableDescriptors.get(regionInfo.getTableName());
-       LOG.debug("HTD for region = " + regionInfo.getRegionNameAsString()
-           + " Is = " + htd );
-       HRegion region =
-         HRegion.openHRegion(hRegion.getRegionInfo(), htd, hlog, conf,
-             this, null);
-       // Add new region to the onlineRegions
-       addToOnlineRegions(region);
-     }
-   }
- }
-
   /**
    * Gets the online regions of the specified table.
    * This method looks at the in-memory onlineRegions.  It does not go to <code>.META.</code>.
@@ -3721,10 +3668,6 @@ public class HRegionServer implements HRegionInterface, HBaseRPCErrorHandler,
      return tableRegions;
    }
 
-  public SchemaChangeTracker getSchemaChangeTracker() {
-    return this.schemaChangeTracker;
-  }
-
   // used by org/apache/hbase/tmpl/regionserver/RSStatusTmpl.jamon (HBASE-4070).
   public String[] getCoprocessors() {
     HServerLoad hsl = buildServerLoad();
@@ -3741,5 +3684,4 @@ public class HRegionServer implements HRegionInterface, HBaseRPCErrorHandler,
         mxBeanInfo);
     LOG.info("Registered RegionServer MXBean");
   }
-
 }

src/main/java/org/apache/hadoop/hbase/regionserver/OnlineRegions.java

@@ -19,12 +19,12 @@
  */
 package org.apache.hadoop.hbase.regionserver;
 
-import org.apache.hadoop.classification.InterfaceAudience;
-import org.apache.hadoop.hbase.Server;
-
 import java.io.IOException;
 import java.util.List;
 
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.hbase.Server;
+
 /**
  * Interface to Map of online regions.  In the  Map, the key is the region's
  * encoded name and the value is an {@link HRegion} instance.
@@ -54,6 +54,7 @@ interface OnlineRegions extends Server {
    * null if named region is not member of the online regions.
    */
   public HRegion getFromOnlineRegions(String encodedRegionName);
+
    /**
     * Get all online regions of a table in this RS.
     * @param tableName
@@ -61,11 +62,4 @@ interface OnlineRegions extends Server {
     * @throws java.io.IOException
     */
    public List<HRegion> getOnlineRegions(byte[] tableName) throws IOException;
-
-  /**
-   * Refresh a given region updating it with latest HTD info.
-   * @param hRegion
-   */
-  public void refreshRegion(HRegion hRegion) throws IOException;
-
 }

src/main/java/org/apache/hadoop/hbase/zookeeper/MasterSchemaChangeTracker.java

@@ -1,828 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.hadoop.hbase.zookeeper;
-
-import java.io.DataInput;
-import java.io.DataOutput;
-import java.io.IOException;
-import java.util.List;
-
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-import org.apache.hadoop.classification.InterfaceAudience;
-import org.apache.hadoop.hbase.Abortable;
-import org.apache.hadoop.hbase.ServerName;
-import org.apache.hadoop.hbase.master.MasterServices;
-import org.apache.hadoop.hbase.monitoring.MonitoredTask;
-import org.apache.hadoop.hbase.monitoring.TaskMonitor;
-import org.apache.hadoop.hbase.util.Bytes;
-import org.apache.hadoop.hbase.util.Writables;
-import org.apache.hadoop.io.Writable;
-import org.apache.zookeeper.KeeperException;
-
-@InterfaceAudience.Private
-public class MasterSchemaChangeTracker extends ZooKeeperNodeTracker {
-  public static final Log LOG = LogFactory.getLog(MasterSchemaChangeTracker.class);
-  private final MasterServices masterServices;
-  // Used by tests only. Do not change this.
-  private volatile int sleepTimeMillis = 0;
-  // schema changes pending more than this time will be timed out.
-  private long schemaChangeTimeoutMillis = 30000;
-
-  /**
-   * Constructs a new ZK node tracker.
-   * <p/>
-   * <p>After construction, use {@link #start} to kick off tracking.
-   *
-   * @param watcher
-   * @param abortable
-   */
-  public MasterSchemaChangeTracker(ZooKeeperWatcher watcher,
-                                   Abortable abortable, MasterServices masterServices,
-                                   long schemaChangeTimeoutMillis) {
-    super(watcher, watcher.schemaZNode, abortable);
-    this.masterServices = masterServices;
-    this.schemaChangeTimeoutMillis = schemaChangeTimeoutMillis;
-  }
-
-  @Override
-  public void start() {
-    try {
-      watcher.registerListener(this);
-      List<String> tables =
-          ZKUtil.listChildrenNoWatch(watcher, watcher.schemaZNode);
-      processCompletedSchemaChanges(tables);
-    } catch (KeeperException e) {
-      LOG.error("MasterSchemaChangeTracker startup failed.", e);
-      abortable.abort("MasterSchemaChangeTracker startup failed", e);
-    }
-  }
-
-  private List<String> getCurrentTables() throws KeeperException {
-    return
-        ZKUtil.listChildrenNoWatch(watcher, watcher.schemaZNode);
-  }
-
-  /**
-   * When a primary master crashes and the secondary master takes over
-   * mid-flight during an alter process, the secondary should cleanup any completed
-   * schema changes not handled by the previous master.
-   * @param tables
-   * @throws KeeperException
-   */
-  private void processCompletedSchemaChanges(List<String> tables)
-      throws KeeperException {
-    if (tables == null || tables.isEmpty()) {
-      String msg = "No current schema change in progress. Skipping cleanup";
-      LOG.debug(msg);
-      return;
-    }
-    String msg = "Master seeing following tables undergoing schema change " +
-        "process. Tables = " + tables;
-    MonitoredTask status = TaskMonitor.get().createStatus(msg);
-    LOG.debug(msg);
-    for (String table : tables) {
-      LOG.debug("Processing table = "+ table);
-      status.setStatus("Processing table = "+ table);
-      try {
-        processTableNode(table);
-      } catch (IOException e) {
-        String errmsg = "IOException while processing completed schema changes."
-            + " Cause = " + e.getCause();
-        LOG.error(errmsg, e);
-        status.setStatus(errmsg);
-      }
-    }
-  }
-
-  /**
-   * Get current alter status for a table.
-   * @param tableName
-   * @return MasterAlterStatus
-   * @throws KeeperException
-   * @throws IOException
-   */
-  public MasterAlterStatus getMasterAlterStatus(String tableName)
-      throws KeeperException, IOException {
-    String path = getSchemaChangeNodePathForTable(tableName);
-    byte[] state = ZKUtil.getData(watcher, path);
-    if (state == null || state.length <= 0) {
-      return null;
-    }
-    MasterAlterStatus mas = new MasterAlterStatus();
-    Writables.getWritable(state, mas);
-    return mas;
-  }
-
-  /**
-   * Get RS specific alter status for a table & server
-   * @param tableName
-   * @param serverName
-   * @return Region Server's Schema alter status
-   * @throws KeeperException
-   * @throws IOException
-   */
-  private SchemaChangeTracker.SchemaAlterStatus getRSSchemaAlterStatus(
-      String tableName, String serverName)
-      throws KeeperException, IOException {
-    String childPath =
-        getSchemaChangeNodePathForTableAndServer(tableName, serverName);
-    byte[] childData = ZKUtil.getData(this.watcher, childPath);
-    if (childData == null || childData.length <= 0) {
-      return null;
-    }
-    SchemaChangeTracker.SchemaAlterStatus sas =
-        new SchemaChangeTracker.SchemaAlterStatus();
-    Writables.getWritable(childData, sas);
-    LOG.debug("Schema Status data for server = " + serverName + " table = "
-        + tableName + " == " + sas);
-    return sas;
-  }
-
-  /**
-   * Update the master's alter status based on all region server's response.
-   * @param servers
-   * @param tableName
-   * @throws IOException
-   */
-  private void updateMasterAlterStatus(MasterAlterStatus mas,
-                                       List<String> servers, String tableName)
-      throws IOException, KeeperException {
-    for (String serverName : servers) {
-      SchemaChangeTracker.SchemaAlterStatus sas =
-          getRSSchemaAlterStatus(tableName, serverName);
-      if (sas != null) {
-        mas.update(sas);
-        LOG.debug("processTableNodeWithState:Updated Master Alter Status = "
-            + mas + " for server = " + serverName);
-      } else {
-        LOG.debug("SchemaAlterStatus is NULL for table = " + tableName);
-      }
-    }
-  }
-
-  /**
-   * If schema alter is handled for this table, then delete all the ZK nodes
-   * created for this table.
-   * @param tableName
-   * @throws KeeperException
-   */
-  private void processTableNode(String tableName) throws KeeperException,
-      IOException {
-    LOG.debug("processTableNodeWithState. TableName = " + tableName);
-    List<String> servers =
-      ZKUtil.listChildrenAndWatchThem(watcher,
-          getSchemaChangeNodePathForTable(tableName));
-    MasterAlterStatus mas = getMasterAlterStatus(tableName);
-    if (mas == null) {
-      LOG.debug("MasterAlterStatus is NULL. Table = " + tableName);
-      return;
-    }
-    updateMasterAlterStatus(mas, servers, tableName);
-    LOG.debug("Current Alter status = " + mas);
-    String nodePath = getSchemaChangeNodePathForTable(tableName);
-    ZKUtil.updateExistingNodeData(this.watcher, nodePath,
-        Writables.getBytes(mas), getZKNodeVersion(nodePath));
-    processAlterStatus(mas, tableName, servers);
-  }
-
-  /**
-   * Evaluate the master alter status and determine the current status.
-   * @param alterStatus
-   * @param tableName
-   * @param servers
-   * @param status
-   */
-  private void processAlterStatus(MasterAlterStatus alterStatus,
-                                  String tableName, List<String> servers)
-  throws KeeperException {
-    if (alterStatus.getNumberOfRegionsToProcess()
-        == alterStatus.getNumberOfRegionsProcessed()) {
-      // schema change completed.
-      String msg = "All region servers have successfully processed the " +
-          "schema changes for table = " + tableName
-          + " . Deleting the schema change node for table = "
-          + tableName + " Region servers processed the schema change" +
-          " request = " + alterStatus.getProcessedHosts()
-          + " Total number of regions = " + alterStatus.getNumberOfRegionsToProcess()
-          + " Processed regions = " + alterStatus.getNumberOfRegionsProcessed();
-      MonitoredTask status = TaskMonitor.get().createStatus(
-          "Checking alter schema request status for table = " + tableName);
-      status.markComplete(msg);
-      LOG.debug(msg);
-      cleanProcessedTableNode(getSchemaChangeNodePathForTable(tableName));
-    } else {
-      if (alterStatus.getErrorCause() != null
-          && alterStatus.getErrorCause().trim().length() > 0) {
-        String msg = "Alter schema change failed "
-            + "for table = " + tableName + " Number of online regions = "
-            + alterStatus.getNumberOfRegionsToProcess() + " processed regions count = "
-            + alterStatus.getNumberOfRegionsProcessed()
-            + " Original list = " + alterStatus.hostsToProcess + " Processed servers = "
-            + servers
-            + " Error Cause = " + alterStatus.getErrorCause();
-        MonitoredTask status = TaskMonitor.get().createStatus(
-            "Checking alter schema request status for table = " + tableName);
-        // we have errors.
-        LOG.debug(msg);
-        status.abort(msg);
-      } else {
-        String msg = "Not all region servers have processed the schema changes"
-            + "for table = " + tableName + " Number of online regions = "
-            + alterStatus.getNumberOfRegionsToProcess() + " processed regions count = "
-            + alterStatus.getNumberOfRegionsProcessed()
-            + " Original list = " + alterStatus.hostsToProcess + " Processed servers = "
-            + servers + " Alter STate = "
-            + alterStatus.getCurrentAlterStatus();
-        LOG.debug(msg);
-        // status.setStatus(msg);
-      }
-    }
-  }
-
-  /**
-   * Check whether a in-flight schema change request has expired.
-   * @param tableName
-   * @return true is the schema change request expired.
-   * @throws IOException
-   */
-  private boolean hasSchemaChangeExpiredFor(String tableName)
-      throws IOException, KeeperException {
-    MasterAlterStatus mas = getMasterAlterStatus(tableName);
-    long createdTimeStamp = mas.getStamp();
-    long duration = System.currentTimeMillis() - createdTimeStamp;
-    LOG.debug("Created TimeStamp = " + createdTimeStamp
-        + " duration = " + duration + " Table = " + tableName
-        + " Master Alter Status = " + mas);
-    return (duration > schemaChangeTimeoutMillis);
-  }
-
-  /**
-   * Handle failed and expired schema changes. We simply delete all the
-   * expired/failed schema change attempts. Why we should do this ?
-   * 1) Keeping the failed/expired schema change nodes longer prohibits any
-   *    future schema changes for the table.
-   * 2) Any lingering expired/failed schema change requests will prohibit the
-   *    load balancer from running.
-   */
-  public void handleFailedOrExpiredSchemaChanges() {
-    try {
-      List<String> tables = getCurrentTables();
-      for (String table : tables) {
-        String statmsg = "Cleaning failed or expired schema change requests. " +
-            "current tables undergoing " +
-            "schema change process = " + tables;
-         MonitoredTask status = TaskMonitor.get().createStatus(statmsg);
-        LOG.debug(statmsg);
-        if (hasSchemaChangeExpiredFor(table)) {
-          // time out.. currently, we abandon the in-flight schema change due to
-          // time out.
-          // Here, there are couple of options to consider. One could be to
-          // attempt a retry of the schema change and see if it succeeds, and
-          // another could be to simply rollback the schema change effort and
-          // see if it succeeds.
-          String msg = "Schema change for table = " + table + " has expired."
-              + " Schema change for this table has been in progress for " +
-              + schemaChangeTimeoutMillis +
-              "Deleting the node now.";
-          LOG.debug(msg);
-          ZKUtil.deleteNodeRecursively(this.watcher,
-              getSchemaChangeNodePathForTable(table));
-        } else {
-          String msg = "Schema change request is in progress for " +
-              " table = " + table;
-          LOG.debug(msg);
-          status.setStatus(msg);
-        }
-      }
-    } catch (IOException e) {
-      String msg = "IOException during handleFailedExpiredSchemaChanges."
-            + e.getCause();
-      LOG.error(msg, e);
-      TaskMonitor.get().createStatus(msg);
-    } catch (KeeperException ke) {
-      String msg = "KeeperException during handleFailedExpiredSchemaChanges."
-          + ke.getCause();
-      LOG.error(msg, ke);
-      TaskMonitor.get().createStatus(msg);
-    }
-  }
-
-  /**
-   * Clean the nodes of completed schema change table.
-   * @param path
-   * @throws KeeperException
-   */
-  private void cleanProcessedTableNode(String path) throws KeeperException {
-    if (sleepTimeMillis > 0) {
-      try {
-        LOG.debug("Master schema change tracker sleeping for "
-            + sleepTimeMillis);
-        Thread.sleep(sleepTimeMillis);
-      } catch (InterruptedException e) {
-        Thread.currentThread().interrupt();
-      }
-    }
-    ZKUtil.deleteNodeRecursively(this.watcher, path);
-    LOG.debug("Deleted all nodes for path " + path);
-
-  }
-
-  /**
-   * Exclude a RS from schema change request (if applicable)
-   * We will exclude a RS from schema change request processing if 1) RS
-   * has online regions for the table AND 2) RS went down mid-flight
-   * during schema change process. We don't have to deal with RS going
-   * down mid-flight during a schema change as the online regions from
-   * the dead RS will get reassigned to some other RS and the
-   * process of reassign inherently takes care of the schema change as well.
-   * @param serverName
-   */
-  public void excludeRegionServerForSchemaChanges(String serverName) {
-    try {
-      MonitoredTask status = TaskMonitor.get().createStatus(
-        "Processing schema change exclusion for region server = " + serverName);
-      List<String> tables =
-            ZKUtil.listChildrenNoWatch(watcher, watcher.schemaZNode);
-      if (tables == null || tables.isEmpty()) {
-        String msg = "No schema change in progress. Skipping exclusion for " +
-            "server = "+ serverName;
-        LOG.debug(msg);
-        status.setStatus(msg);
-        return ;
-      }
-      for (String tableName : tables) {
-        excludeRegionServer(tableName, serverName, status);
-      }
-    } catch(KeeperException ke) {
-      LOG.error("KeeperException during excludeRegionServerForSchemaChanges", ke);
-    } catch(IOException ioe) {
-      LOG.error("IOException during excludeRegionServerForSchemaChanges", ioe);
-
-    }
-  }
-
-  /**
-   * Check whether a schema change is in progress for a given table on a
-   * given RS.
-   * @param tableName
-   * @param serverName
-   * @return TRUE is this RS is currently processing a schema change request
-   * for the table.
-   * @throws KeeperException
-   */
-  private boolean isSchemaChangeApplicableFor(String tableName,
-                                              String serverName)
-      throws KeeperException {
-    List<String> servers = ZKUtil.listChildrenAndWatchThem(watcher,
-        getSchemaChangeNodePathForTable(tableName));
-    return (servers.contains(serverName));
-  }
-
-  /**
-   * Exclude a region server for a table (if applicable) from schema change processing.
-   * @param tableName
-   * @param serverName
-   * @param status
-   * @throws KeeperException
-   * @throws IOException
-   */
-  private void excludeRegionServer(String tableName, String serverName,
-                                   MonitoredTask status)
-      throws KeeperException, IOException {
-    if (isSchemaChangeApplicableFor(tableName, serverName)) {
-      String msg = "Excluding RS " + serverName + " from schema change process" +
-          " for table = " + tableName;
-      LOG.debug(msg);
-      status.setStatus(msg);
-      SchemaChangeTracker.SchemaAlterStatus sas =
-          getRSSchemaAlterStatus(tableName, serverName);
-      if (sas == null) {
-        LOG.debug("SchemaAlterStatus is NULL for table = " + tableName
-            + " server = " + serverName);
-        return;
-      }
-      // Set the status to IGNORED so we can process it accordingly.
-      sas.setCurrentAlterStatus(
-          SchemaChangeTracker.SchemaAlterStatus.AlterState.IGNORED);
-      LOG.debug("Updating the current schema status to " + sas);
-      String nodePath = getSchemaChangeNodePathForTableAndServer(tableName,
-              serverName);
-      ZKUtil.updateExistingNodeData(this.watcher,
-          nodePath, Writables.getBytes(sas), getZKNodeVersion(nodePath));
-    } else {
-      LOG.debug("Skipping exclusion of RS " + serverName
-          + " from schema change process"
-          + " for table = " + tableName
-          + " as it did not possess any online regions for the table");
-    }
-    processTableNode(tableName);
-  }
-
-  private int getZKNodeVersion(String nodePath) throws KeeperException {
-    return ZKUtil.checkExists(this.watcher, nodePath);
-  }
-
-  /**
-   * Create a new schema change ZK node.
-   * @param tableName Table name that is getting altered
-   * @throws KeeperException
-   */
-  public void createSchemaChangeNode(String tableName,
-                                     int numberOfRegions)
-      throws KeeperException, IOException {
-    MonitoredTask status = TaskMonitor.get().createStatus(
-        "Creating schema change node for table = " + tableName);
-    LOG.debug("Creating schema change node for table = "
-        + tableName + " Path = "
-        + getSchemaChangeNodePathForTable(tableName));
-    if (doesSchemaChangeNodeExists(tableName)) {
-      LOG.debug("Schema change node already exists for table = " + tableName
-          + " Deleting the schema change node.");
-      // If we already see a schema change node for this table we wait till the previous
-      // alter process is complete. Ideally, we need not wait and we could simply delete
-      // existing schema change node for this table and create new one. But then the
-      // RS cloud will not be able to process concurrent schema updates for the same table
-      // as they will be working with same set of online regions for this table. Meaning the
-      // second alter change will not see any online regions (as they were being closed and
-      // re opened by the first change) and will miss the second one.
-      // We either handle this at the RS level using explicit locks while processing a table
-      // or do it here. I prefer doing it here as it seems much simpler and cleaner.
-      while(doesSchemaChangeNodeExists(tableName)) {
-        try {
-          Thread.sleep(50);
-        } catch (InterruptedException e) {
-          Thread.currentThread().interrupt();
-        }
-      }
-    }
-
-    int rsCount = ZKUtil.getNumberOfChildren(this.watcher, watcher.rsZNode);
-    // if number of online RS = 0, we should not do anything!
-    if (rsCount <= 0) {
-      String msg = "Master is not seeing any online region servers. Aborting the " +
-          "schema change processing by region servers.";
-      LOG.debug(msg);
-      status.abort(msg);
-    } else {
-      LOG.debug("Master is seeing " + rsCount + " region servers online before " +
-          "the schema change process.");
-      MasterAlterStatus mas = new MasterAlterStatus(numberOfRegions,
-          getActiveRegionServersAsString());
-      LOG.debug("Master creating the master alter status = " + mas);
-      ZKUtil.createSetData(this.watcher,
-          getSchemaChangeNodePathForTable(tableName), Writables.getBytes(mas));
-      status.markComplete("Created the ZK node for schema change. Current Alter Status = "
-          + mas.toString());
-      ZKUtil.listChildrenAndWatchThem(this.watcher,
-          getSchemaChangeNodePathForTable(tableName));
-    }
-  }
-
-  private String getActiveRegionServersAsString() {
-    StringBuffer sbuf = new StringBuffer();
-    List<ServerName> currentRS =
-        masterServices.getRegionServerTracker().getOnlineServers();
-    for (ServerName serverName : currentRS) {
-      sbuf.append(serverName.getServerName());
-      sbuf.append(" ");
-    }
-    LOG.debug("Current list of RS to process the schema change = "
-        + sbuf.toString());
-    return sbuf.toString();
-  }
-
-  /**
-   * Create a new schema change ZK node.
-   * @param tableName
-   * @throws KeeperException
-   */
-  public boolean doesSchemaChangeNodeExists(String tableName)
-      throws KeeperException {
-    return ZKUtil.checkExists(watcher,
-            getSchemaChangeNodePathForTable(tableName)) != -1;
-  }
-
-  /**
-   * Check whether there are any schema change requests that are in progress now.
-   * We simply assume that a schema change is in progress if we see a ZK schema node for
-   * any table. We may revisit for fine grained checks such as check the current alter status
-   * et al, but it is not required now.
-   * @return
-   */
-  public boolean isSchemaChangeInProgress() {
-    try {
-      int schemaChangeCount = ZKUtil.getNumberOfChildren(this.watcher, watcher.schemaZNode);
-      return schemaChangeCount > 0;
-    } catch (KeeperException ke) {
-      LOG.debug("KeeperException while getting current schema change progress.");
-      // What do we do now??? currently reporting as false.
-    }
-    return false;
-  }
-
-  /**
-   * We get notified when a RS processes/or completed the schema change request.
-   * The path will be of the format /hbase/schema/<table name>
-   * @param path full path of the node whose children have changed
-   */
-  @Override
-  public void nodeChildrenChanged(String path) {
-    String tableName = null;
-    if (path.startsWith(watcher.schemaZNode) &&
-        !path.equals(watcher.schemaZNode)) {
-      try {
-        LOG.debug("NodeChildrenChanged Path = " + path);
-        tableName = path.substring(path.lastIndexOf("/")+1, path.length());
-        processTableNode(tableName);
-      } catch (KeeperException e) {
-        TaskMonitor.get().createStatus(
-        "MasterSchemaChangeTracker: ZK exception while processing " +
-            " nodeChildrenChanged() event for table = " + tableName
-            + " Cause = " + e.getCause());
-        LOG.error("MasterSchemaChangeTracker: Unexpected zk exception getting"
-            + " schema change nodes", e);
-      } catch(IOException ioe) {
-        TaskMonitor.get().createStatus(
-        "MasterSchemaChangeTracker: ZK exception while processing " +
-            " nodeChildrenChanged() event for table = " + tableName
-            + " Cause = " + ioe.getCause());
-        LOG.error("MasterSchemaChangeTracker: Unexpected IO exception getting"
-            + " schema change nodes", ioe);
-      }
-    }
-  }
-
-  /**
-   * We get notified as and when the RS cloud updates their ZK nodes with
-   * progress information. The path will be of the format
-   * /hbase/schema/<table name>/<RS host name>
-   * @param path
-   */
-  @Override
-  public void nodeDataChanged(String path) {
-    String tableName = null;
-    if (path.startsWith(watcher.schemaZNode) &&
-        !path.equals(watcher.schemaZNode)) {
-      try {
-        LOG.debug("NodeDataChanged Path = " + path);
-        String[] paths = path.split("/");
-        tableName = paths[3];
-        processTableNode(tableName);
-      } catch (KeeperException e) {
-        TaskMonitor.get().createStatus(
-        "MasterSchemaChangeTracker: ZK exception while processing " +
-            " nodeDataChanged() event for table = " + tableName
-            + " Cause = " + e.getCause());
-        LOG.error("MasterSchemaChangeTracker: Unexpected zk exception getting"
-            + " schema change nodes", e);
-      } catch(IOException ioe) {
-        TaskMonitor.get().createStatus(
-        "MasterSchemaChangeTracker: IO exception while processing " +
-            " nodeDataChanged() event for table = " + tableName
-            + " Cause = " + ioe.getCause());
-        LOG.error("MasterSchemaChangeTracker: Unexpected IO exception getting"
-            + " schema change nodes", ioe);
-
-      }
-    }
-  }
-
-  public String getSchemaChangeNodePathForTable(String tableName) {
-    return ZKUtil.joinZNode(watcher.schemaZNode, tableName);
-  }
-
-  /**
-   * Used only for tests. Do not use this. See TestInstantSchemaChange for more details
-   * on how this is getting used. This is primarily used to delay the schema complete
-   * processing by master so that we can test some complex scenarios such as
-   * master failover.
-   * @param sleepTimeMillis
-   */
-  public void setSleepTimeMillis(int sleepTimeMillis) {
-    this.sleepTimeMillis = sleepTimeMillis;
-  }
-
-  private String getSchemaChangeNodePathForTableAndServer(
-      String tableName, String regionServerName) {
-    return ZKUtil.joinZNode(getSchemaChangeNodePathForTable(tableName),
-        regionServerName);
-  }
-
-
-  /**
-   * Holds the current alter state for a table. Alter state includes the
-   * current alter status (INPROCESS, FAILURE or SUCCESS (success is not getting
-   * used now.), timestamp of alter request, number of hosts online at the time
-   * of alter request, number of online regions to process for the schema change
-   * request, number of processed regions and a list of region servers that
-   * actually processed the schema change request.
-   *
-   * Master keeps track of schema change requests using the alter status and
-   * periodically updates the alter status based on RS cloud processings.
-   */
-  public static class MasterAlterStatus implements Writable {
-
-    public enum AlterState {
-      INPROCESS,        // Inprocess alter
-      SUCCESS,          // completed alter
-      FAILURE           // failure alter
-    }
-
-    private AlterState currentAlterStatus;
-    // TimeStamp
-    private long stamp;
-    private int numberOfRegionsToProcess;
-    private StringBuffer errorCause = new StringBuffer(" ");
-    private StringBuffer processedHosts = new StringBuffer(" ");
-    private String hostsToProcess;
-    private int numberOfRegionsProcessed = 0;
-
-    public MasterAlterStatus() {
-
-    }
-
-    public MasterAlterStatus(int numberOfRegions, String activeHosts) {
-      this.numberOfRegionsToProcess = numberOfRegions;
-      this.stamp = System.currentTimeMillis();
-      this.currentAlterStatus = AlterState.INPROCESS;
-      //this.rsToProcess = activeHosts;
-      this.hostsToProcess = activeHosts;
-    }
-
-    public AlterState getCurrentAlterStatus() {
-      return currentAlterStatus;
-    }
-
-    public void setCurrentAlterStatus(AlterState currentAlterStatus) {
-      this.currentAlterStatus = currentAlterStatus;
-    }
-
-    public long getStamp() {
-      return stamp;
-    }
-
-    public void setStamp(long stamp) {
-      this.stamp = stamp;
-    }
-
-    public int getNumberOfRegionsToProcess() {
-      return numberOfRegionsToProcess;
-    }
-
-    public void setNumberOfRegionsToProcess(int numberOfRegionsToProcess) {
-      this.numberOfRegionsToProcess = numberOfRegionsToProcess;
-    }
-
-    public int getNumberOfRegionsProcessed() {
-      return numberOfRegionsProcessed;
-    }
-
-    public void setNumberOfRegionsProcessed(int numberOfRegionsProcessed) {
-      this.numberOfRegionsProcessed += numberOfRegionsProcessed;
-    }
-
-    public String getHostsToProcess() {
-      return hostsToProcess;
-    }
-
-    public void setHostsToProcess(String hostsToProcess) {
-      this.hostsToProcess = hostsToProcess;
-    }
-
-    public String getErrorCause() {
-      return errorCause == null ? null : errorCause.toString();
-    }
-
-    public void setErrorCause(String errorCause) {
-      if (errorCause == null || errorCause.trim().length() <= 0) {
-        return;
-      }
-      if (this.errorCause == null) {
-        this.errorCause = new StringBuffer(errorCause);
-      } else {
-        this.errorCause.append(errorCause);
-      }
-    }
-
-    public String getProcessedHosts() {
-      return processedHosts.toString();
-    }
-
-    public void setProcessedHosts(String processedHosts) {
-      if (this.processedHosts == null) {
-        this.processedHosts = new StringBuffer(processedHosts);
-      } else {
-        this.processedHosts.append(" ").append(processedHosts);
-      }
-    }
-
-    /**
-     * Ignore or exempt a RS from schema change processing.
-     * Master will tweak the number of regions to process based on the
-     * number of online regions on the target RS and also remove the
-     * RS from list of hosts to process.
-     * @param schemaAlterStatus
-     */
-    private void ignoreRSForSchemaChange(
-        SchemaChangeTracker.SchemaAlterStatus schemaAlterStatus) {
-      LOG.debug("Removing RS " + schemaAlterStatus.getHostName()
-          + " from schema change process.");
-      hostsToProcess =
-          hostsToProcess.replaceAll(schemaAlterStatus.getHostName(), "");
-      int ignoreRegionsCount = schemaAlterStatus.getNumberOfOnlineRegions();
-      LOG.debug("Current number of regions processed = "
-          + this.numberOfRegionsProcessed + " deducting ignored = "
-          + ignoreRegionsCount
-          + " final = " + (this.numberOfRegionsToProcess-ignoreRegionsCount));
-      if (this.numberOfRegionsToProcess > 0) {
-        this.numberOfRegionsToProcess -= ignoreRegionsCount;
-      } else {
-        LOG.debug("Number of regions to process is less than zero. This is odd");
-      }
-    }
-
-    /**
-     * Update the master alter status for this table based on RS alter status.
-     * @param schemaAlterStatus
-     */
-    public void update(SchemaChangeTracker.SchemaAlterStatus schemaAlterStatus) {
-      this.setProcessedHosts(schemaAlterStatus.getHostName());
-      SchemaChangeTracker.SchemaAlterStatus.AlterState rsState =
-          schemaAlterStatus.getCurrentAlterStatus();
-      switch(rsState) {
-        case FAILURE:
-          LOG.debug("Schema update failure Status = "
-            + schemaAlterStatus);
-          this.setCurrentAlterStatus(
-              MasterAlterStatus.AlterState.FAILURE);
-          this.setNumberOfRegionsProcessed(
-              schemaAlterStatus.getNumberOfRegionsProcessed());
-          this.setErrorCause(schemaAlterStatus.getErrorCause());
-          break;
-        case SUCCESS:
-          LOG.debug("Schema update SUCCESS Status = "
-            + schemaAlterStatus);
-          this.setNumberOfRegionsProcessed(
-              schemaAlterStatus.getNumberOfRegionsProcessed());
-          this.setCurrentAlterStatus(MasterAlterStatus.AlterState.SUCCESS);
-          break;
-        case IGNORED:
-          LOG.debug("Schema update IGNORED Updating regions to " +
-              "process count. Status = "+ schemaAlterStatus);
-          ignoreRSForSchemaChange(schemaAlterStatus);
-          break;
-        default:
-            break;
-      }
-    }
-
-    @Override
-    public void readFields(DataInput in) throws IOException {
-      currentAlterStatus = AlterState.valueOf(in.readUTF());
-      stamp = in.readLong();
-      numberOfRegionsToProcess = in.readInt();
-      hostsToProcess = Bytes.toString(Bytes.readByteArray(in));
-      processedHosts = new StringBuffer(Bytes.toString(Bytes.readByteArray(in)));
-      errorCause = new StringBuffer(Bytes.toString(Bytes.readByteArray(in)));
-    }
-
-    @Override
-    public void write(DataOutput out) throws IOException {
-      out.writeUTF(currentAlterStatus.name());
-      out.writeLong(stamp);
-      out.writeInt(numberOfRegionsToProcess);
-      Bytes.writeByteArray(out, Bytes.toBytes(hostsToProcess));
-      Bytes.writeByteArray(out, Bytes.toBytes(processedHosts.toString()));
-      Bytes.writeByteArray(out, Bytes.toBytes(errorCause.toString()));
-    }
-
-    @Override
-    public String toString() {
-      return
-         " state= " + currentAlterStatus
-        + ", ts= " + stamp
-        + ", number of regions to process = " + numberOfRegionsToProcess
-        + ", number of regions processed = " + numberOfRegionsProcessed
-        + ", hosts = " + hostsToProcess
-        + " , processed hosts = " + processedHosts
-        + " , errorCause = " + errorCause;
-    }
-  }
-}

src/main/java/org/apache/hadoop/hbase/zookeeper/SchemaChangeTracker.java

@@ -1,478 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.hadoop.hbase.zookeeper;
-
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-import org.apache.hadoop.classification.InterfaceAudience;
-import org.apache.hadoop.hbase.Abortable;
-import org.apache.hadoop.hbase.monitoring.MonitoredTask;
-import org.apache.hadoop.hbase.monitoring.TaskMonitor;
-import org.apache.hadoop.hbase.regionserver.HRegion;
-import org.apache.hadoop.hbase.regionserver.RegionServerServices;
-import org.apache.hadoop.hbase.util.Bytes;
-import org.apache.hadoop.hbase.util.Writables;
-import org.apache.zookeeper.KeeperException;
-import org.apache.hadoop.hbase.util.Writables;
-
-import org.apache.hadoop.io.Writable;
-
-import java.io.*;
-import java.util.List;
-
-/**
- * Region server schema change tracker. RS uses this tracker to keep track of
- * alter schema requests from master and updates the status once the schema change
- * is complete.
- */
-@InterfaceAudience.Private
-public class SchemaChangeTracker extends ZooKeeperNodeTracker {
-  public static final Log LOG = LogFactory.getLog(SchemaChangeTracker.class);
-  private RegionServerServices regionServer = null;
-  private volatile int sleepTimeMillis = 0;
-
-
-  /**
-   * Constructs a new ZK node tracker.
-   * <p/>
-   * <p>After construction, use {@link #start} to kick off tracking.
-   *
-   * @param watcher
-   * @param node
-   * @param abortable
-   */
-  public SchemaChangeTracker(ZooKeeperWatcher watcher,
-                             Abortable abortable,
-                             RegionServerServices regionServer) {
-    super(watcher, watcher.schemaZNode, abortable);
-    this.regionServer = regionServer;
-  }
-
-  @Override
-  public void start() {
-    try {
-      watcher.registerListener(this);
-      ZKUtil.listChildrenAndWatchThem(watcher, node);
-      // Clean-up old in-process schema changes for this RS now?
-    } catch (KeeperException e) {
-      LOG.error("RegionServer SchemaChangeTracker startup failed with " +
-          "KeeperException.", e);
-    }
-  }
-
-
-  /**
-   * This event will be triggered whenever new schema change request is processed by the
-   * master. The path will be of the format /hbase/schema/<table name>
-   * @param path full path of the node whose children have changed
-   */
-  @Override
-  public void nodeChildrenChanged(String path) {
-    LOG.debug("NodeChildrenChanged. Path = " + path);
-    if (path.equals(watcher.schemaZNode)) {
-      try {
-        List<String> tables =
-          ZKUtil.listChildrenAndWatchThem(watcher, watcher.schemaZNode);
-        LOG.debug("RS.SchemaChangeTracker: " +
-            "Current list of tables with schema change = " + tables);
-        if (tables != null) {
-          handleSchemaChange(tables);
-        } else {
-          LOG.error("No tables found for schema change event." +
-              " Skipping instant schema refresh");
-        }
-      } catch (KeeperException ke) {
-        String errmsg = "KeeperException while handling nodeChildrenChanged for path = "
-            + path + " Cause = " + ke.getCause();
-        LOG.error(errmsg, ke);
-        TaskMonitor.get().createStatus(errmsg);
-      }
-    }
-  }
-
-  private void handleSchemaChange(List<String> tables) {
-    for (String tableName : tables) {
-      if (tableName != null) {
-        LOG.debug("Processing schema change with status for table = " + tableName);
-        handleSchemaChange(tableName);
-      }
-    }
-  }
-
-  private void handleSchemaChange(String tableName) {
-    int refreshedRegionsCount = 0, onlineRegionsCount = 0;
-    MonitoredTask status = null;
-    try {
-      List<HRegion> onlineRegions =
-          regionServer.getOnlineRegions(Bytes.toBytes(tableName));
-      if (onlineRegions != null && !onlineRegions.isEmpty()) {
-        status = TaskMonitor.get().createStatus("Region server "
-             + regionServer.getServerName().getServerName()
-             + " handling schema change for table = " + tableName
-             + " number of online regions = " + onlineRegions.size());
-        onlineRegionsCount = onlineRegions.size();
-        createStateNode(tableName, onlineRegions.size());
-        for (HRegion hRegion : onlineRegions) {
-          regionServer.refreshRegion(hRegion);
-          refreshedRegionsCount ++;
-        }
-        SchemaAlterStatus alterStatus = getSchemaAlterStatus(tableName);
-        alterStatus.update(SchemaAlterStatus.AlterState.SUCCESS, refreshedRegionsCount);
-        updateSchemaChangeStatus(tableName, alterStatus);
-        String msg = "Refresh schema completed for table name = " + tableName
-        + " server = " + regionServer.getServerName().getServerName()
-        + " online Regions = " + onlineRegions.size()
-        + " refreshed Regions = " + refreshedRegionsCount;
-        LOG.debug(msg);
-        status.setStatus(msg);
-      } else {
-        LOG.debug("Server " + regionServer.getServerName().getServerName()
-         + " has no online regions for table = " + tableName
-         + " Ignoring the schema change request");
-      }
-    } catch (IOException ioe) {
-      reportAndLogSchemaRefreshError(tableName, onlineRegionsCount,
-          refreshedRegionsCount, ioe, status);
-    } catch (KeeperException ke) {
-      reportAndLogSchemaRefreshError(tableName, onlineRegionsCount,
-          refreshedRegionsCount, ke, status);
-    }
-  }
-
-  private int getZKNodeVersion(String nodePath) throws KeeperException {
-    return ZKUtil.checkExists(this.watcher, nodePath);
-  }
-
-  private void reportAndLogSchemaRefreshError(String tableName,
-                                              int onlineRegionsCount,
-                                              int refreshedRegionsCount,
-                                              Throwable exception,
-                                              MonitoredTask status) {
-    try {
-      String errmsg =
-          " Region Server " + regionServer.getServerName().getServerName()
-              + " failed during schema change process. Cause = "
-              + exception.getCause()
-              + " Number of onlineRegions = " + onlineRegionsCount
-              + " Processed regions = " + refreshedRegionsCount;
-      SchemaAlterStatus alterStatus = getSchemaAlterStatus(tableName);
-      alterStatus.update(SchemaAlterStatus.AlterState.FAILURE,
-          refreshedRegionsCount, errmsg);
-      String nodePath = getSchemaChangeNodePathForTableAndServer(tableName,
-              regionServer.getServerName().getServerName());
-      ZKUtil.updateExistingNodeData(this.watcher, nodePath,
-          Writables.getBytes(alterStatus), getZKNodeVersion(nodePath));
-      LOG.info("reportAndLogSchemaRefreshError() " +
-          " Updated child ZKNode with SchemaAlterStatus = "
-          + alterStatus + " for table = " + tableName);
-      if (status == null) {
-        status = TaskMonitor.get().createStatus(errmsg);
-      } else {
-        status.setStatus(errmsg);
-      }
-    } catch (KeeperException e) {
-    // Retry ?
-      String errmsg = "KeeperException while updating the schema change node with "
-        + "error status for table = "
-        + tableName + " server = "
-        + regionServer.getServerName().getServerName()
-        + " Cause = " + e.getCause();
-      LOG.error(errmsg, e);
-      TaskMonitor.get().createStatus(errmsg);
-    } catch(IOException ioe) {
-      // retry ??
-      String errmsg = "IOException while updating the schema change node with "
-        + "server name for table = "
-        + tableName + " server = "
-        + regionServer.getServerName().getServerName()
-        + " Cause = " + ioe.getCause();
-      TaskMonitor.get().createStatus(errmsg);
-      LOG.error(errmsg, ioe);
-    }
-  }
-
-
-  private void createStateNode(String tableName, int numberOfOnlineRegions)
-      throws IOException {
-    SchemaAlterStatus sas =
-        new SchemaAlterStatus(regionServer.getServerName().getServerName(),
-            numberOfOnlineRegions);
-    LOG.debug("Creating Schema Alter State node = " + sas);
-    try {
-      ZKUtil.createSetData(this.watcher,
-          getSchemaChangeNodePathForTableAndServer(tableName,
-                regionServer.getServerName().getServerName()),
-                Writables.getBytes(sas));
-    } catch (KeeperException ke) {
-      String errmsg = "KeeperException while creating the schema change node with "
-          + "server name for table = "
-          + tableName + " server = "
-          + regionServer.getServerName().getServerName()
-          + " Message = " + ke.getCause();
-      LOG.error(errmsg, ke);
-      TaskMonitor.get().createStatus(errmsg);
-    }
-
-  }
-
-  private SchemaAlterStatus getSchemaAlterStatus(String tableName)
-      throws KeeperException, IOException {
-    byte[] statusBytes = ZKUtil.getData(this.watcher,
-        getSchemaChangeNodePathForTableAndServer(tableName,
-            regionServer.getServerName().getServerName()));
-    if (statusBytes == null || statusBytes.length <= 0) {
-      return null;
-    }
-    SchemaAlterStatus sas = new SchemaAlterStatus();
-    Writables.getWritable(statusBytes, sas);
-    return sas;
-  }
-
-  private void updateSchemaChangeStatus(String tableName,
-                                     SchemaAlterStatus schemaAlterStatus)
-      throws KeeperException, IOException {
-    try {
-      if(sleepTimeMillis > 0) {
-        try {
-          LOG.debug("SchemaChangeTracker sleeping for "
-              + sleepTimeMillis);
-          Thread.sleep(sleepTimeMillis);
-        } catch (InterruptedException e) {
-          Thread.currentThread().interrupt();
-        }
-      }
-      ZKUtil.updateExistingNodeData(this.watcher,
-          getSchemaChangeNodePathForTableAndServer(tableName,
-              regionServer.getServerName().getServerName()),
-          Writables.getBytes(schemaAlterStatus), -1);
-      String msg = "Schema change tracker completed for table = " + tableName
-              + " status = " + schemaAlterStatus;
-      LOG.debug(msg);
-      TaskMonitor.get().createStatus(msg);
-    } catch (KeeperException.NoNodeException e) {
-      String errmsg = "KeeperException.NoNodeException while updating the schema "
-          + "change node with server name for table = "
-          + tableName + " server = "
-          + regionServer.getServerName().getServerName()
-          + " Cause = " + e.getCause();
-      TaskMonitor.get().createStatus(errmsg);
-      LOG.error(errmsg, e);
-    } catch (KeeperException e) {
-      // Retry ?
-      String errmsg = "KeeperException while updating the schema change node with "
-          + "server name for table = "
-          + tableName + " server = "
-          + regionServer.getServerName().getServerName()
-          + " Cause = " + e.getCause();
-      LOG.error(errmsg, e);
-      TaskMonitor.get().createStatus(errmsg);
-    } catch(IOException ioe) {
-      String errmsg = "IOException while updating the schema change node with "
-          + "server name for table = "
-          + tableName + " server = "
-          + regionServer.getServerName().getServerName()
-          + " Cause = " + ioe.getCause();
-      LOG.error(errmsg, ioe);
-      TaskMonitor.get().createStatus(errmsg);
-    }
-  }
-
-  private String getSchemaChangeNodePathForTable(String tableName) {
-    return ZKUtil.joinZNode(watcher.schemaZNode, tableName);
-  }
-
-  private String getSchemaChangeNodePathForTableAndServer(
-      String tableName, String regionServerName) {
-    return ZKUtil.joinZNode(getSchemaChangeNodePathForTable(tableName),
-        regionServerName);
-  }
-
-  public int getSleepTimeMillis() {
-    return sleepTimeMillis;
-  }
-
-  /**
-   * Set a sleep time in millis before this RS can update it's progress status.
-   * Used only for test cases to test complex test scenarios such as RS failures and
-   * RS exemption handling.
-   * @param sleepTimeMillis
-   */
-  public void setSleepTimeMillis(int sleepTimeMillis) {
-    this.sleepTimeMillis = sleepTimeMillis;
-  }
-
-  /**
-   * Check whether there are any schema change requests that are in progress now for the given table.
-   * We simply assume that a schema change is in progress if we see a ZK schema node this
-   * any table. We may revisit for fine grained checks such as check the current alter status
-   * et al, but it is not required now.
-   * @return
-   */
-  public boolean isSchemaChangeInProgress(String tableName) {
-    try {
-      List<String> schemaChanges = ZKUtil.listChildrenAndWatchThem(this.watcher,
-          watcher.schemaZNode);
-      if (schemaChanges != null) {
-        for (String alterTableName : schemaChanges) {
-          if (alterTableName.equals(tableName)) {
-            return true;
-          }
-        }
-        return false;
-      }
-    } catch (KeeperException ke) {
-      LOG.debug("isSchemaChangeInProgress. " +
-          "KeeperException while getting current schema change progress.");
-      return false;
-    }
-    return false;
-  }
-
-  /**
-   * Holds the current alter state for a table. Alter state includes the
-   * current alter status (INPROCESS, FAILURE, SUCCESS, or IGNORED, current RS
-   * host name, timestamp of alter request, number of online regions this RS has for
-   * the given table, number of processed regions and an errorCause in case
-   * if the RS failed during the schema change process.
-   *
-   * RS keeps track of schema change requests per table using the alter status and
-   * periodically updates the alter status based on schema change status.
-   */
-  public static class SchemaAlterStatus implements Writable {
-
-    public enum AlterState {
-      INPROCESS,        // Inprocess alter
-      SUCCESS,          // completed alter
-      FAILURE,          // failure alter
-      IGNORED           // Ignore the alter processing.
-    }
-
-    private AlterState currentAlterStatus;
-    // TimeStamp
-    private long stamp;
-    private int numberOfOnlineRegions;
-    private String errorCause = " ";
-    private String hostName;
-    private int numberOfRegionsProcessed = 0;
-
-    public SchemaAlterStatus() {
-
-    }
-
-    public SchemaAlterStatus(String hostName, int numberOfOnlineRegions) {
-      this.numberOfOnlineRegions = numberOfOnlineRegions;
-      this.stamp = System.currentTimeMillis();
-      this.currentAlterStatus = AlterState.INPROCESS;
-      //this.rsToProcess = activeHosts;
-      this.hostName = hostName;
-    }
-
-    public AlterState getCurrentAlterStatus() {
-      return currentAlterStatus;
-    }
-
-    public void setCurrentAlterStatus(AlterState currentAlterStatus) {
-      this.currentAlterStatus = currentAlterStatus;
-    }
-
-    public int getNumberOfOnlineRegions() {
-      return numberOfOnlineRegions;
-    }
-
-    public void setNumberOfOnlineRegions(int numberOfRegions) {
-      this.numberOfOnlineRegions = numberOfRegions;
-    }
-
-    public int getNumberOfRegionsProcessed() {
-      return numberOfRegionsProcessed;
-    }
-
-    public void setNumberOfRegionsProcessed(int numberOfRegionsProcessed) {
-      this.numberOfRegionsProcessed = numberOfRegionsProcessed;
-    }
-
-    public String getErrorCause() {
-      return errorCause;
-    }
-
-    public void setErrorCause(String errorCause) {
-      this.errorCause = errorCause;
-    }
-
-    public String getHostName() {
-      return hostName;
-    }
-
-    public void setHostName(String hostName) {
-      this.hostName = hostName;
-    }
-
-    public void update(AlterState state, int numberOfRegions, String errorCause) {
-      this.currentAlterStatus = state;
-      this.numberOfRegionsProcessed = numberOfRegions;
-      this.errorCause = errorCause;
-    }
-
-    public void update(AlterState state, int numberOfRegions) {
-      this.currentAlterStatus = state;
-      this.numberOfRegionsProcessed = numberOfRegions;
-    }
-
-    public void update(AlterState state) {
-      this.currentAlterStatus = state;
-    }
-
-    public void update(SchemaAlterStatus status) {
-      this.currentAlterStatus = status.getCurrentAlterStatus();
-      this.numberOfRegionsProcessed = status.getNumberOfRegionsProcessed();
-      this.errorCause = status.getErrorCause();
-    }
-
-    @Override
-    public void readFields(DataInput in) throws IOException {
-      currentAlterStatus = AlterState.valueOf(in.readUTF());
-      stamp = in.readLong();
-      numberOfOnlineRegions = in.readInt();
-      hostName = Bytes.toString(Bytes.readByteArray(in));
-      numberOfRegionsProcessed = in.readInt();
-      errorCause = Bytes.toString(Bytes.readByteArray(in));
-    }
-
-    @Override
-    public void write(DataOutput out) throws IOException {
-      out.writeUTF(currentAlterStatus.name());
-      out.writeLong(stamp);
-      out.writeInt(numberOfOnlineRegions);
-      Bytes.writeByteArray(out, Bytes.toBytes(hostName));
-      out.writeInt(numberOfRegionsProcessed);
-      Bytes.writeByteArray(out, Bytes.toBytes(errorCause));
-    }
-
-    @Override
-    public String toString() {
-      return
-         " state= " + currentAlterStatus
-        + ", ts= " + stamp
-        + ", number of online regions = " + numberOfOnlineRegions
-        + ", host= " + hostName + " processed regions = " + numberOfRegionsProcessed
-        + ", errorCause = " + errorCause;
-    }
-  }
-
-}

src/main/java/org/apache/hadoop/hbase/zookeeper/ZooKeeperWatcher.java

@@ -102,8 +102,6 @@ public class ZooKeeperWatcher implements Watcher, Abortable, Closeable {
   public String clusterIdZNode;
   // znode used for log splitting work assignment
   public String splitLogZNode;
-  // znode used to record table schema changes
-  public String schemaZNode;
 
   // Certain ZooKeeper nodes need to be world-readable
   public static final ArrayList<ACL> CREATOR_ALL_AND_WORLD_READABLE =
@@ -166,7 +164,6 @@ public class ZooKeeperWatcher implements Watcher, Abortable, Closeable {
       ZKUtil.createAndFailSilent(this, drainingZNode);
       ZKUtil.createAndFailSilent(this, tableZNode);
       ZKUtil.createAndFailSilent(this, splitLogZNode);
-      ZKUtil.createAndFailSilent(this, schemaZNode);
       ZKUtil.createAndFailSilent(this, backupMasterAddressesZNode);
     } catch (KeeperException e) {
       throw new ZooKeeperConnectionException(
@@ -215,8 +212,6 @@ public class ZooKeeperWatcher implements Watcher, Abortable, Closeable {
         conf.get("zookeeper.znode.clusterId", "hbaseid"));
     splitLogZNode = ZKUtil.joinZNode(baseZNode,
         conf.get("zookeeper.znode.splitlog", HConstants.SPLIT_LOGDIR_NAME));
-    schemaZNode = ZKUtil.joinZNode(baseZNode,
-                conf.get("zookeeper.znode.schema", "schema"));
   }
 
   /**

src/main/resources/hbase-default.xml

@@ -790,30 +790,6 @@
       simplify coprocessor failure analysis.
       </description>
   </property>
-  <property>
-    <name>hbase.instant.schema.alter.enabled</name>
-    <value>false</value>
-    <description>Whether or not to handle alter schema changes instantly or not.
-    If enabled, all schema change alter operations will be instant, as the master will not
-    explicitly unassign/assign the impacted regions and instead will rely on Region servers to
-    refresh their schema changes. If enabled, the schema alter requests will survive
-    master or RS failures.
-    </description>
-  </property>
-  <property>
-    <name>hbase.instant.schema.janitor.period</name>
-    <value>120000</value>
-    <description>The Schema Janitor process wakes up every millis and sweeps all
-    expired/failed schema change requests.
-    </description>
-  </property>
-  <property>
-    <name>hbase.instant.schema.alter.timeout</name>
-    <value>60000</value>
-    <description>Timeout in millis after which any pending schema alter request will be
-    considered as failed.
-    </description>
-  </property>
   <property>
     <name>hbase.online.schema.update.enable</name>
     <value>false</value>

src/test/java/org/apache/hadoop/hbase/client/InstantSchemaChangeTestBase.java

@@ -1,169 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.hadoop.hbase.client;
-
-import static org.junit.Assert.assertEquals;
-
-import java.io.IOException;
-import java.util.List;
-
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-import org.apache.hadoop.conf.Configuration;
-import org.apache.hadoop.hbase.HBaseTestingUtility;
-import org.apache.hadoop.hbase.HConstants;
-import org.apache.hadoop.hbase.HTableDescriptor;
-import org.apache.hadoop.hbase.LargeTests;
-import org.apache.hadoop.hbase.MiniHBaseCluster;
-import org.apache.hadoop.hbase.regionserver.HRegion;
-import org.apache.hadoop.hbase.regionserver.HRegionServer;
-import org.apache.hadoop.hbase.util.Bytes;
-import org.apache.hadoop.hbase.util.JVMClusterUtil;
-import org.apache.hadoop.hbase.zookeeper.MasterSchemaChangeTracker;
-import org.apache.zookeeper.KeeperException;
-import org.junit.After;
-import org.junit.Before;
-import org.junit.experimental.categories.Category;
-
-@Category(LargeTests.class)
-public class InstantSchemaChangeTestBase {
-
-  final Log LOG = LogFactory.getLog(getClass());
-  protected final static HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
-  protected HBaseAdmin admin;
-  protected static MiniHBaseCluster miniHBaseCluster = null;
-  protected Configuration conf;
-  protected static MasterSchemaChangeTracker msct = null;
-
-  protected final byte [] row = Bytes.toBytes("row");
-  protected final byte [] qualifier = Bytes.toBytes("qualifier");
-  final byte [] value = Bytes.toBytes("value");
-
-  @Before
-  public void setUpBeforeClass() throws Exception {
-    TEST_UTIL.getConfiguration().setInt("hbase.regionserver.msginterval", 100);
-    TEST_UTIL.getConfiguration().setInt("hbase.client.pause", 250);
-    TEST_UTIL.getConfiguration().setInt("hbase.client.retries.number", 6);
-    TEST_UTIL.getConfiguration().setBoolean("hbase.instant.schema.alter.enabled", true);
-    TEST_UTIL.getConfiguration().setBoolean("hbase.online.schema.update.enable", true);
-    TEST_UTIL.getConfiguration().setInt("hbase.instant.schema.janitor.period", 10000);
-    TEST_UTIL.getConfiguration().setInt("hbase.instant.schema.alter.timeout", 30000);
-    //
-    miniHBaseCluster = TEST_UTIL.startMiniCluster(2,5);
-    msct = TEST_UTIL.getHBaseCluster().getMaster().getSchemaChangeTracker();
-    this.admin = new HBaseAdmin(TEST_UTIL.getConfiguration());
-
-  }
-
-  @After
-  public void tearDownAfterClass() throws Exception {
-    TEST_UTIL.shutdownMiniCluster();
-  }
-
-  /**
-   * Find the RS that is currently holding our online region.
-   * @param tableName
-   * @return
-   */
-  protected HRegionServer findRSWithOnlineRegionFor(String tableName) {
-    List<JVMClusterUtil.RegionServerThread> rsThreads =
-        miniHBaseCluster.getLiveRegionServerThreads();
-    for (JVMClusterUtil.RegionServerThread rsT : rsThreads) {
-      HRegionServer rs = rsT.getRegionServer();
-      List<HRegion> regions = rs.getOnlineRegions(Bytes.toBytes(tableName));
-      if (regions != null && !regions.isEmpty()) {
-        return rs;
-      }
-    }
-    return null;
-  }
-
-  protected void waitForSchemaChangeProcess(final String tableName)
-      throws KeeperException, InterruptedException {
-    waitForSchemaChangeProcess(tableName, 10000);
-  }
-
-  /**
-   * This a pretty low cost signalling mechanism. It is quite possible that we will
-   * miss out the ZK node creation signal as in some cases the schema change process
-   * happens rather quickly and our thread waiting for ZK node creation might wait forver.
-   * The fool-proof strategy would be to directly listen for ZK events.
-   * @param tableName
-   * @throws KeeperException
-   * @throws InterruptedException
-   */
-  protected void waitForSchemaChangeProcess(final String tableName, final long waitTimeMills)
-      throws KeeperException, InterruptedException {
-    LOG.info("Waiting for ZK node creation for table = " + tableName);
-    final MasterSchemaChangeTracker msct =
-    TEST_UTIL.getHBaseCluster().getMaster().getSchemaChangeTracker();
-    final Runnable r = new Runnable() {
-      public void run() {
-        try {
-          while(!msct.doesSchemaChangeNodeExists(tableName)) {
-            try {
-              Thread.sleep(50);
-            } catch (InterruptedException e) {
-              Thread.currentThread().interrupt();
-            }
-          }
-        } catch (KeeperException ke) {
-            ke.printStackTrace();
-        }
-        LOG.info("Waiting for ZK node deletion for table = " + tableName);
-        try {
-          while(msct.doesSchemaChangeNodeExists(tableName)) {
-            try {
-              Thread.sleep(50);
-            } catch (InterruptedException e) {
-               Thread.currentThread().interrupt();
-            }
-          }
-        }  catch (KeeperException ke) {
-            ke.printStackTrace();
-        }
-      }
-    };
-    Thread t = new Thread(r);
-    t.start();
-    if (waitTimeMills > 0) {
-      t.join(waitTimeMills);
-    }  else {
-      t.join(10000);
-    }
-  }
-
-  protected HTable createTableAndValidate(String tableName) throws IOException {
-    conf = TEST_UTIL.getConfiguration();
-    LOG.info("Start createTableAndValidate()");
-    TEST_UTIL.getHBaseCluster().getMaster().getSchemaChangeTracker();
-    HTableDescriptor[] tables = admin.listTables();
-    int numTables = 0;
-    if (tables != null) {
-      numTables = tables.length;
-    }
-    HTable ht = TEST_UTIL.createTable(Bytes.toBytes(tableName),
-      HConstants.CATALOG_FAMILY);
-    tables = this.admin.listTables();
-    assertEquals(numTables + 1, tables.length);
-    LOG.info("created table = " + tableName);
-    return ht;
-  }
-
-}

src/test/java/org/apache/hadoop/hbase/client/TestInstantSchemaChange.java

@@ -1,473 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.hadoop.hbase.client;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-import java.io.IOException;
-import java.util.List;
-
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-import org.apache.hadoop.hbase.HColumnDescriptor;
-import org.apache.hadoop.hbase.HConstants;
-import org.apache.hadoop.hbase.HTableDescriptor;
-import org.apache.hadoop.hbase.LargeTests;
-import org.apache.hadoop.hbase.regionserver.HRegion;
-import org.apache.hadoop.hbase.util.Bytes;
-import org.apache.hadoop.hbase.zookeeper.MasterSchemaChangeTracker;
-import org.apache.zookeeper.KeeperException;
-import org.junit.Test;
-import org.junit.experimental.categories.Category;
-
-@Category(LargeTests.class)
-public class TestInstantSchemaChange extends InstantSchemaChangeTestBase {
-
-  final Log LOG = LogFactory.getLog(getClass());
-
-  @Test
-  public void testInstantSchemaChangeForModifyTable() throws IOException,
-      KeeperException, InterruptedException {
-
-    String tableName = "testInstantSchemaChangeForModifyTable";
-    conf = TEST_UTIL.getConfiguration();
-    LOG.info("Start testInstantSchemaChangeForModifyTable()");
-    HTable ht = createTableAndValidate(tableName);
-
-    String newFamily = "newFamily";
-    HTableDescriptor htd = new HTableDescriptor(tableName);
-    htd.addFamily(new HColumnDescriptor(newFamily));
-
-    admin.modifyTable(Bytes.toBytes(tableName), htd);
-    waitForSchemaChangeProcess(tableName);
-    assertFalse(msct.doesSchemaChangeNodeExists(tableName));
-
-    Put put1 = new Put(row);
-    put1.add(Bytes.toBytes(newFamily), qualifier, value);
-    ht.put(put1);
-
-    Get get1 = new Get(row);
-    get1.addColumn(Bytes.toBytes(newFamily), qualifier);
-    Result r = ht.get(get1);
-    byte[] tvalue = r.getValue(Bytes.toBytes(newFamily), qualifier);
-    int result = Bytes.compareTo(value, tvalue);
-    assertEquals(result, 0);
-    LOG.info("END testInstantSchemaChangeForModifyTable()");
-    ht.close();
-  }
-
-  @Test
-  public void testInstantSchemaChangeForAddColumn() throws IOException,
-      KeeperException, InterruptedException {
-    LOG.info("Start testInstantSchemaChangeForAddColumn() ");
-    String tableName = "testSchemachangeForAddColumn";
-    HTable ht = createTableAndValidate(tableName);
-    String newFamily = "newFamily";
-    HColumnDescriptor hcd = new HColumnDescriptor("newFamily");
-
-    admin.addColumn(Bytes.toBytes(tableName), hcd);
-    waitForSchemaChangeProcess(tableName);
-    assertFalse(msct.doesSchemaChangeNodeExists(tableName));
-
-    Put put1 = new Put(row);
-    put1.add(Bytes.toBytes(newFamily), qualifier, value);
-    LOG.info("******** Put into new column family ");
-    ht.put(put1);
-
-    Get get1 = new Get(row);
-    get1.addColumn(Bytes.toBytes(newFamily), qualifier);
-    Result r = ht.get(get1);
-    byte[] tvalue = r.getValue(Bytes.toBytes(newFamily), qualifier);
-    LOG.info(" Value put = " + value + " value from table = " + tvalue);
-    int result = Bytes.compareTo(value, tvalue);
-    assertEquals(result, 0);
-    LOG.info("End testInstantSchemaChangeForAddColumn() ");
-    ht.close();
- }
-
-  @Test
-  public void testInstantSchemaChangeForModifyColumn() throws IOException,
-      KeeperException, InterruptedException {
-    LOG.info("Start testInstantSchemaChangeForModifyColumn() ");
-    String tableName = "testSchemachangeForModifyColumn";
-    createTableAndValidate(tableName);
-
-    HColumnDescriptor hcd = new HColumnDescriptor(HConstants.CATALOG_FAMILY);
-    hcd.setMaxVersions(99);
-    hcd.setBlockCacheEnabled(false);
-
-    admin.modifyColumn(Bytes.toBytes(tableName), hcd);
-    waitForSchemaChangeProcess(tableName);
-    assertFalse(msct.doesSchemaChangeNodeExists(tableName));
-
-    List<HRegion> onlineRegions
-        = miniHBaseCluster.getRegions(Bytes.toBytes("testSchemachangeForModifyColumn"));
-    for (HRegion onlineRegion : onlineRegions) {
-      HTableDescriptor htd = onlineRegion.getTableDesc();
-      HColumnDescriptor tableHcd = htd.getFamily(HConstants.CATALOG_FAMILY);
-      assertTrue(tableHcd.isBlockCacheEnabled() == false);
-      assertEquals(tableHcd.getMaxVersions(), 99);
-    }
-    LOG.info("End testInstantSchemaChangeForModifyColumn() ");
-
- }
-
-  @Test
-  public void testInstantSchemaChangeForDeleteColumn() throws IOException,
-      KeeperException, InterruptedException {
-    LOG.info("Start testInstantSchemaChangeForDeleteColumn() ");
-    String tableName = "testSchemachangeForDeleteColumn";
-    int numTables = 0;
-    HTableDescriptor[] tables = admin.listTables();
-    if (tables != null) {
-      numTables = tables.length;
-    }
-
-    byte[][] FAMILIES = new byte[][] {
-      Bytes.toBytes("A"), Bytes.toBytes("B"), Bytes.toBytes("C") };
-
-    HTable ht = TEST_UTIL.createTable(Bytes.toBytes(tableName),
-      FAMILIES);
-    tables = this.admin.listTables();
-    assertEquals(numTables + 1, tables.length);
-    LOG.info("Table testSchemachangeForDeleteColumn created");
-
-    admin.deleteColumn(tableName, "C");
-
-    waitForSchemaChangeProcess(tableName);
-    assertFalse(msct.doesSchemaChangeNodeExists(tableName));
-    HTableDescriptor modifiedHtd = this.admin.getTableDescriptor(Bytes.toBytes(tableName));
-    HColumnDescriptor hcd = modifiedHtd.getFamily(Bytes.toBytes("C"));
-    assertTrue(hcd == null);
-    LOG.info("End testInstantSchemaChangeForDeleteColumn() ");
-    ht.close();
- }
-
-  @Test
-  public void testInstantSchemaChangeWhenTableIsNotEnabled() throws IOException,
-      KeeperException {
-    final String tableName = "testInstantSchemaChangeWhenTableIsDisabled";
-    conf = TEST_UTIL.getConfiguration();
-    LOG.info("Start testInstantSchemaChangeWhenTableIsDisabled()");
-    HTable ht = createTableAndValidate(tableName);
-    // Disable table
-    admin.disableTable("testInstantSchemaChangeWhenTableIsDisabled");
-    // perform schema changes
-    HColumnDescriptor hcd = new HColumnDescriptor("newFamily");
-    admin.addColumn(Bytes.toBytes(tableName), hcd);
-    MasterSchemaChangeTracker msct =
-    TEST_UTIL.getHBaseCluster().getMaster().getSchemaChangeTracker();
-    assertTrue(msct.doesSchemaChangeNodeExists(tableName) == false);
-    ht.close();
-  }
-
-  /**
-   * Test that when concurrent alter requests are received for a table we don't miss any.
-   * @throws IOException
-   * @throws KeeperException
-   * @throws InterruptedException
-   */
-  @Test
-  public void testConcurrentInstantSchemaChangeForAddColumn() throws IOException,
-      KeeperException, InterruptedException {
-    final String tableName = "testConcurrentInstantSchemaChangeForModifyTable";
-    conf = TEST_UTIL.getConfiguration();
-    LOG.info("Start testConcurrentInstantSchemaChangeForModifyTable()");
-    HTable ht = createTableAndValidate(tableName);
-
-    Runnable run1 = new Runnable() {
-      public void run() {
-        HColumnDescriptor hcd = new HColumnDescriptor("family1");
-        try {
-          admin.addColumn(Bytes.toBytes(tableName), hcd);
-        } catch (IOException ioe) {
-          ioe.printStackTrace();
-
-        }
-      }
-    };
-    Runnable run2 = new Runnable() {
-      public void run() {
-        HColumnDescriptor hcd = new HColumnDescriptor("family2");
-        try {
-          admin.addColumn(Bytes.toBytes(tableName), hcd);
-        } catch (IOException ioe) {
-          ioe.printStackTrace();
-
-        }
-      }
-    };
-
-    run1.run();
-    // We have to add a sleep here as in concurrent scenarios the HTD update
-    // in HDFS fails and returns with null HTD. This needs to be investigated,
-    // but it doesn't impact the instant alter functionality in any way.
-    Thread.sleep(100);
-    run2.run();
-
-    waitForSchemaChangeProcess(tableName);
-
-    Put put1 = new Put(row);
-    put1.add(Bytes.toBytes("family1"), qualifier, value);
-    ht.put(put1);
-
-    Get get1 = new Get(row);
-    get1.addColumn(Bytes.toBytes("family1"), qualifier);
-    Result r = ht.get(get1);
-    byte[] tvalue = r.getValue(Bytes.toBytes("family1"), qualifier);
-    int result = Bytes.compareTo(value, tvalue);
-    assertEquals(result, 0);
-    Thread.sleep(10000);
-
-    Put put2 = new Put(row);
-    put2.add(Bytes.toBytes("family2"), qualifier, value);
-    ht.put(put2);
-
-    Get get2 = new Get(row);
-    get2.addColumn(Bytes.toBytes("family2"), qualifier);
-    Result r2 = ht.get(get2);
-    byte[] tvalue2 = r2.getValue(Bytes.toBytes("family2"), qualifier);
-    int result2 = Bytes.compareTo(value, tvalue2);
-    assertEquals(result2, 0);
-    LOG.info("END testConcurrentInstantSchemaChangeForModifyTable()");
-    ht.close();
-  }
-
-  /**
-   * The schema change request blocks while a LB run is in progress. This
-   * test validates this behavior.
-   * @throws IOException
-   * @throws InterruptedException
-   * @throws KeeperException
-   */
-  @Test
-  public void testConcurrentInstantSchemaChangeAndLoadBalancerRun() throws IOException,
-      InterruptedException, KeeperException {
-    final String tableName = "testInstantSchemaChangeWithLoadBalancerRunning";
-    conf = TEST_UTIL.getConfiguration();
-    LOG.info("Start testInstantSchemaChangeWithLoadBalancerRunning()");
-    final String newFamily = "newFamily";
-    HTable ht = createTableAndValidate(tableName);
-    final MasterSchemaChangeTracker msct =
-    TEST_UTIL.getHBaseCluster().getMaster().getSchemaChangeTracker();
-
-
-    Runnable balancer = new Runnable() {
-      public void run() {
-        // run the balancer now.
-        miniHBaseCluster.getMaster().balance();
-      }
-    };
-
-    Runnable schemaChanger = new Runnable() {
-      public void run() {
-        HColumnDescriptor hcd = new HColumnDescriptor(newFamily);
-        try {
-          admin.addColumn(Bytes.toBytes(tableName), hcd);
-        } catch (IOException ioe) {
-          ioe.printStackTrace();
-
-        }
-      }
-    };
-
-    balancer.run();
-    schemaChanger.run();
-    waitForSchemaChangeProcess(tableName, 40000);
-    assertFalse(msct.doesSchemaChangeNodeExists(tableName));
-
-    Put put1 = new Put(row);
-    put1.add(Bytes.toBytes(newFamily), qualifier, value);
-    LOG.info("******** Put into new column family ");
-    ht.put(put1);
-    ht.flushCommits();
-
-    LOG.info("******** Get from new column family ");
-    Get get1 = new Get(row);
-    get1.addColumn(Bytes.toBytes(newFamily), qualifier);
-    Result r = ht.get(get1);
-    byte[] tvalue = r.getValue(Bytes.toBytes(newFamily), qualifier);
-    LOG.info(" Value put = " + value + " value from table = " + tvalue);
-    int result = Bytes.compareTo(value, tvalue);
-    assertEquals(result, 0);
-
-    LOG.info("End testInstantSchemaChangeWithLoadBalancerRunning() ");
-    ht.close();
-  }
-
-
-  /**
-   * This test validates two things. One is that the LoadBalancer does not run when a schema
-   * change process is in progress. The second thing is that it also checks that failed/expired
-   * schema changes are expired to unblock the load balancer run.
-   *
-   */
-  @Test (timeout=70000)
-  public void testLoadBalancerBlocksDuringSchemaChangeRequests() throws KeeperException,
-      IOException, InterruptedException {
-    LOG.info("Start testConcurrentLoadBalancerSchemaChangeRequests() ");
-    final MasterSchemaChangeTracker msct =
-    TEST_UTIL.getHBaseCluster().getMaster().getSchemaChangeTracker();
-    // Test that the load balancer does not run while an in-flight schema
-    // change operation is in progress.
-    // Simulate a new schema change request.
-    msct.createSchemaChangeNode("testLoadBalancerBlocks", 0);
-    // The schema change node is created.
-    assertTrue(msct.doesSchemaChangeNodeExists("testLoadBalancerBlocks"));
-    // Now, request an explicit LB run.
-
-    Runnable balancer1 = new Runnable() {
-      public void run() {
-        // run the balancer now.
-        miniHBaseCluster.getMaster().balance();
-      }
-    };
-    balancer1.run();
-
-    // Load balancer should not run now.
-    assertTrue(miniHBaseCluster.getMaster().isLoadBalancerRunning() == false);
-    LOG.debug("testConcurrentLoadBalancerSchemaChangeRequests Asserted");
-    LOG.info("End testConcurrentLoadBalancerSchemaChangeRequests() ");
-  }
-
-  /**
-   * Test that instant schema change blocks while LB is running.
-   * @throws KeeperException
-   * @throws IOException
-   * @throws InterruptedException
-   */
-  @Test (timeout=10000)
-  public void testInstantSchemaChangeBlocksDuringLoadBalancerRun() throws KeeperException,
-      IOException, InterruptedException {
-    final MasterSchemaChangeTracker msct =
-    TEST_UTIL.getHBaseCluster().getMaster().getSchemaChangeTracker();
-
-    final String tableName = "testInstantSchemaChangeBlocksDuringLoadBalancerRun";
-    conf = TEST_UTIL.getConfiguration();
-    LOG.info("Start testInstantSchemaChangeBlocksDuringLoadBalancerRun()");
-    final String newFamily = "newFamily";
-    createTableAndValidate(tableName);
-
-    // Test that the schema change request does not run while an in-flight LB run
-    // is in progress.
-    // First, request an explicit LB run.
-
-    Runnable balancer1 = new Runnable() {
-      public void run() {
-        // run the balancer now.
-        miniHBaseCluster.getMaster().balance();
-      }
-    };
-
-    Runnable schemaChanger = new Runnable() {
-      public void run() {
-        HColumnDescriptor hcd = new HColumnDescriptor(newFamily);
-        try {
-          admin.addColumn(Bytes.toBytes(tableName), hcd);
-        } catch (IOException ioe) {
-          ioe.printStackTrace();
-
-        }
-      }
-    };
-
-    Thread t1 = new Thread(balancer1);
-    Thread t2 = new Thread(schemaChanger);
-    t1.start();
-    t2.start();
-
-    // check that they both happen concurrently
-    Runnable balancerCheck = new Runnable() {
-      public void run() {
-        // check whether balancer is running.
-        while(!miniHBaseCluster.getMaster().isLoadBalancerRunning()) {
-          try {
-            Thread.sleep(10);
-          } catch (InterruptedException e) {
-            Thread.currentThread().interrupt();
-          }
-        }
-        try {
-           assertFalse(msct.doesSchemaChangeNodeExists("testSchemaChangeBlocks"));
-        } catch (KeeperException ke) {
-          ke.printStackTrace();
-        }
-        LOG.debug("Load Balancer is now running or skipped");
-        while(miniHBaseCluster.getMaster().isLoadBalancerRunning()) {
-          try {
-            Thread.sleep(10);
-          } catch (InterruptedException e) {
-            Thread.currentThread().interrupt();
-          }
-        }
-        assertTrue(miniHBaseCluster.getMaster().isLoadBalancerRunning() == false);
-        try {
-          assertTrue(msct.doesSchemaChangeNodeExists("testSchemaChangeBlocks"));
-        } catch (KeeperException ke) {
-
-        }
-
-      }
-    };
-
-    Thread t = new Thread(balancerCheck);
-    t.start();
-    t.join(1000);
-    // Load balancer should not run now.
-    //assertTrue(miniHBaseCluster.getMaster().isLoadBalancerRunning() == false);
-    // Schema change request node should now exist.
-   // assertTrue(msct.doesSchemaChangeNodeExists("testSchemaChangeBlocks"));
-    LOG.debug("testInstantSchemaChangeBlocksDuringLoadBalancerRun Asserted");
-    LOG.info("End testInstantSchemaChangeBlocksDuringLoadBalancerRun() ");
-  }
-
-  /**
-   * To test the schema janitor (that it cleans expired/failed schema alter attempts) we
-   * simply create a fake table (that doesn't exist, with fake number of online regions) in ZK.
-   * This schema alter request will time out (after 30 seconds) and our janitor will clean it up.
-   * regions
-   * @throws IOException
-   * @throws KeeperException
-   * @throws InterruptedException
-   */
-  @Test
-  public void testInstantSchemaJanitor() throws IOException,
-      KeeperException, InterruptedException {
-    LOG.info("testInstantSchemaWithFailedExpiredOperations() ");
-    String fakeTableName = "testInstantSchemaWithFailedExpiredOperations";
-    MasterSchemaChangeTracker msct =
-    TEST_UTIL.getHBaseCluster().getMaster().getSchemaChangeTracker();
-    msct.createSchemaChangeNode(fakeTableName, 10);
-    LOG.debug(msct.getSchemaChangeNodePathForTable(fakeTableName)
-        + " created");
-    Thread.sleep(40000);
-    assertFalse(msct.doesSchemaChangeNodeExists(fakeTableName));
-    LOG.debug(msct.getSchemaChangeNodePathForTable(fakeTableName)
-        + " deleted");
-    LOG.info("END testInstantSchemaWithFailedExpiredOperations() ");
-  }
-
-
-
-  @org.junit.Rule
-  public org.apache.hadoop.hbase.ResourceCheckerJUnitRule cu =
-    new org.apache.hadoop.hbase.ResourceCheckerJUnitRule();
-}

src/test/java/org/apache/hadoop/hbase/client/TestInstantSchemaChangeFailover.java

@@ -1,313 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.apache.hadoop.hbase.client;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-import java.io.IOException;
-
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-import org.apache.hadoop.conf.Configuration;
-import org.apache.hadoop.hbase.HBaseTestingUtility;
-import org.apache.hadoop.hbase.HColumnDescriptor;
-import org.apache.hadoop.hbase.HConstants;
-import org.apache.hadoop.hbase.HTableDescriptor;
-import org.apache.hadoop.hbase.LargeTests;
-import org.apache.hadoop.hbase.MiniHBaseCluster;
-import org.apache.hadoop.hbase.util.Bytes;
-import org.apache.hadoop.hbase.zookeeper.MasterSchemaChangeTracker;
-import org.apache.hadoop.hbase.zookeeper.ZKUtil;
-import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
-import org.apache.zookeeper.KeeperException;
-import org.junit.After;
-import org.junit.Before;
-import org.junit.Ignore;
-import org.junit.Test;
-import org.junit.experimental.categories.Category;
-
-@Category(LargeTests.class)
-public class TestInstantSchemaChangeFailover {
-
-  final Log LOG = LogFactory.getLog(getClass());
-  private final static HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
-  private HBaseAdmin admin;
-  private static MiniHBaseCluster miniHBaseCluster = null;
-  private Configuration conf;
-  private ZooKeeperWatcher zkw;
-  private static MasterSchemaChangeTracker msct = null;
-
-  private final byte [] row = Bytes.toBytes("row");
-  private final byte [] qualifier = Bytes.toBytes("qualifier");
-  final byte [] value = Bytes.toBytes("value");
-
-  @Before
-  public void setUpBeforeClass() throws Exception {
-    TEST_UTIL.getConfiguration().setInt("hbase.regionserver.msginterval", 100);
-    TEST_UTIL.getConfiguration().setInt("hbase.client.pause", 250);
-    TEST_UTIL.getConfiguration().setInt("hbase.client.retries.number", 6);
-    TEST_UTIL.getConfiguration().setBoolean("hbase.online.schema.update.enable", true);
-    TEST_UTIL.getConfiguration().setBoolean("hbase.instant.schema.alter.enabled", true);
-    TEST_UTIL.getConfiguration().setInt("hbase.instant.schema.janitor.period", 10000);
-    TEST_UTIL.getConfiguration().setInt("hbase.instant.schema.alter.timeout", 30000);
-    //
-    miniHBaseCluster = TEST_UTIL.startMiniCluster(2,5);
-    msct = TEST_UTIL.getHBaseCluster().getMaster().getSchemaChangeTracker();
-    this.admin = new HBaseAdmin(TEST_UTIL.getConfiguration());
-  }
-
-  @After
-  public void tearDownAfterClass() throws Exception {
-    TEST_UTIL.shutdownMiniCluster();
-  }
-
-  /**
-   * This a pretty low cost signalling mechanism. It is quite possible that we will
-   * miss out the ZK node creation signal as in some cases the schema change process
-   * happens rather quickly and our thread waiting for ZK node creation might wait forver.
-   * The fool-proof strategy would be to directly listen for ZK events.
-   * @param tableName
-   * @throws KeeperException
-   * @throws InterruptedException
-   */
-  private void waitForSchemaChangeProcess(final String tableName)
-      throws KeeperException, InterruptedException {
-    LOG.info("Waiting for ZK node creation for table = " + tableName);
-    final MasterSchemaChangeTracker msct =
-    TEST_UTIL.getHBaseCluster().getMaster().getSchemaChangeTracker();
-    final Runnable r = new Runnable() {
-      public void run() {
-        try {
-          while(!msct.doesSchemaChangeNodeExists(tableName)) {
-            try {
-              Thread.sleep(20);
-            } catch (InterruptedException e) {
-            Thread.currentThread().interrupt();
-            }
-          }
-        } catch (KeeperException ke) {
-            ke.printStackTrace();
-        }
-
-        LOG.info("Waiting for ZK node deletion for table = " + tableName);
-        try {
-          while(msct.doesSchemaChangeNodeExists(tableName)) {
-            try {
-              Thread.sleep(20);
-            } catch (InterruptedException e) {
-              Thread.currentThread().interrupt();
-            }
-          }
-        } catch (KeeperException ke) {
-         ke.printStackTrace();
-        }
-      }
-    };
-    Thread t = new Thread(r);
-    t.start();
-    t.join(10000);
-  }
-
-
-  /**
-   * Kill a random RS and see that the schema change can succeed.
-   * @throws IOException
-   * @throws KeeperException
-   * @throws InterruptedException
-   */
-  @Test (timeout=50000)
-  public void testInstantSchemaChangeWhileRSCrash() throws IOException,
-      KeeperException, InterruptedException {
-    LOG.info("Start testInstantSchemaChangeWhileRSCrash()");
-    zkw = miniHBaseCluster.getMaster().getZooKeeperWatcher();
-
-    final String tableName = "TestRSCrashDuringSchemaChange";
-    HTable ht = createTableAndValidate(tableName);
-    HColumnDescriptor hcd = new HColumnDescriptor("family2");
-    admin.addColumn(Bytes.toBytes(tableName), hcd);
-
-    miniHBaseCluster.getRegionServer(0).abort("Killing while instant schema change");
-    // Let the dust settle down
-    Thread.sleep(10000);
-    waitForSchemaChangeProcess(tableName);
-    Put put2 = new Put(row);
-    put2.add(Bytes.toBytes("family2"), qualifier, value);
-    ht.put(put2);
-
-    Get get2 = new Get(row);
-    get2.addColumn(Bytes.toBytes("family2"), qualifier);
-    Result r2 = ht.get(get2);
-    byte[] tvalue2 = r2.getValue(Bytes.toBytes("family2"), qualifier);
-    int result2 = Bytes.compareTo(value, tvalue2);
-    assertEquals(result2, 0);
-    String nodePath = msct.getSchemaChangeNodePathForTable("TestRSCrashDuringSchemaChange");
-    assertTrue(ZKUtil.checkExists(zkw, nodePath) == -1);
-    LOG.info("result2 = " + result2);
-    LOG.info("end testInstantSchemaChangeWhileRSCrash()");
-    ht.close();
-  }
-
-  /**
-   * Randomly bring down/up RS servers while schema change is in progress. This test
-   * is same as the above one but the only difference is that we intent to kill and start
-   * new RS instances while a schema change is in progress.
-   * @throws IOException
-   * @throws KeeperException
-   * @throws InterruptedException
-   */
-  @Test (timeout=70000)
-  public void testInstantSchemaChangeWhileRandomRSCrashAndStart() throws IOException,
-      KeeperException, InterruptedException {
-    LOG.info("Start testInstantSchemaChangeWhileRandomRSCrashAndStart()");
-    miniHBaseCluster.getRegionServer(4).abort("Killing RS 4");
-    // Start a new RS before schema change .
-    // Commenting the start RS as it is failing with DFS user permission NPE.
-    //miniHBaseCluster.startRegionServer();
-
-    // Let the dust settle
-    Thread.sleep(10000);
-    final String tableName = "testInstantSchemaChangeWhileRandomRSCrashAndStart";
-    HTable ht = createTableAndValidate(tableName);
-    HColumnDescriptor hcd = new HColumnDescriptor("family2");
-    admin.addColumn(Bytes.toBytes(tableName), hcd);
-    // Kill 2 RS now.
-    miniHBaseCluster.getRegionServer(2).abort("Killing RS 2");
-    // Let the dust settle
-    Thread.sleep(10000);
-    // We will be left with only one RS.
-    waitForSchemaChangeProcess(tableName);
-    assertFalse(msct.doesSchemaChangeNodeExists(tableName));
-    Put put2 = new Put(row);
-    put2.add(Bytes.toBytes("family2"), qualifier, value);
-    ht.put(put2);
-
-    Get get2 = new Get(row);
-    get2.addColumn(Bytes.toBytes("family2"), qualifier);
-    Result r2 = ht.get(get2);
-    byte[] tvalue2 = r2.getValue(Bytes.toBytes("family2"), qualifier);
-    int result2 = Bytes.compareTo(value, tvalue2);
-    assertEquals(result2, 0);
-    LOG.info("result2 = " + result2);
-    LOG.info("end testInstantSchemaChangeWhileRandomRSCrashAndStart()");
-    ht.close();
-  }
-
-  /**
-   * Test scenario where primary master is brought down while processing an
-   * alter request. This is harder one as it is very difficult the time this.
-   * @throws IOException
-   * @throws KeeperException
-   * @throws InterruptedException
-   */
-
-  @Test (timeout=50000)
-  public void testInstantSchemaChangeWhileMasterFailover() throws IOException,
-      KeeperException, InterruptedException {
-    LOG.info("Start testInstantSchemaChangeWhileMasterFailover()");
-    //Thread.sleep(5000);
-
-    final String tableName = "testInstantSchemaChangeWhileMasterFailover";
-    HTable ht = createTableAndValidate(tableName);
-    HColumnDescriptor hcd = new HColumnDescriptor("family2");
-    admin.addColumn(Bytes.toBytes(tableName), hcd);
-    // Kill primary master now.
-    Thread.sleep(50);
-    miniHBaseCluster.getMaster().abort("Aborting master now", new Exception("Schema exception"));
-
-    // It may not be possible for us to check the schema change status
-    // using waitForSchemaChangeProcess as our ZK session in MasterSchemachangeTracker will be
-    // lost when master dies and hence may not be accurate. So relying on old-fashioned
-    // sleep here.
-    Thread.sleep(25000);
-    Put put2 = new Put(row);
-    put2.add(Bytes.toBytes("family2"), qualifier, value);
-    ht.put(put2);
-
-    Get get2 = new Get(row);
-    get2.addColumn(Bytes.toBytes("family2"), qualifier);
-    Result r2 = ht.get(get2);
-    byte[] tvalue2 = r2.getValue(Bytes.toBytes("family2"), qualifier);
-    int result2 = Bytes.compareTo(value, tvalue2);
-    assertEquals(result2, 0);
-    LOG.info("result2 = " + result2);
-    LOG.info("end testInstantSchemaChangeWhileMasterFailover()");
-    ht.close();
-  }
-
-  /**
-   * TEst the master fail over during a schema change request in ZK.
-   * We create a fake schema change request in ZK and abort the primary master
-   * mid-flight to simulate a master fail over scenario during a mid-flight
-   * schema change process. The new master's schema janitor will eventually
-   * cleanup this fake request after time out.
-   * @throws IOException
-   * @throws KeeperException
-   * @throws InterruptedException
-   */
-  @Ignore
-  @Test
-  public void testInstantSchemaOperationsInZKForMasterFailover() throws IOException,
-      KeeperException, InterruptedException {
-    LOG.info("testInstantSchemaOperationsInZKForMasterFailover() ");
-    String tableName = "testInstantSchemaOperationsInZKForMasterFailover";
-
-    conf = TEST_UTIL.getConfiguration();
-    MasterSchemaChangeTracker activesct =
-    TEST_UTIL.getHBaseCluster().getMaster().getSchemaChangeTracker();
-    activesct.createSchemaChangeNode(tableName, 10);
-    LOG.debug(activesct.getSchemaChangeNodePathForTable(tableName)
-        + " created");
-    assertTrue(activesct.doesSchemaChangeNodeExists(tableName));
-    // Kill primary master now.
-    miniHBaseCluster.getMaster().abort("Aborting master now", new Exception("Schema exception"));
-    // wait for 50 secs. This is so that our schema janitor from fail-over master will kick-in and
-    // cleanup this failed/expired schema change request.
-    Thread.sleep(50000);
-    MasterSchemaChangeTracker newmsct = miniHBaseCluster.getMaster().getSchemaChangeTracker();
-    assertFalse(newmsct.doesSchemaChangeNodeExists(tableName));
-    LOG.debug(newmsct.getSchemaChangeNodePathForTable(tableName)
-        + " deleted");
-    LOG.info("END testInstantSchemaOperationsInZKForMasterFailover() ");
-  }
-
-  private HTable createTableAndValidate(String tableName) throws IOException {
-    conf = TEST_UTIL.getConfiguration();
-    LOG.info("Start createTableAndValidate()");
-    HTableDescriptor[] tables = admin.listTables();
-    int numTables = 0;
-    if (tables != null) {
-      numTables = tables.length;
-    }
-    HTable ht = TEST_UTIL.createTable(Bytes.toBytes(tableName),
-      HConstants.CATALOG_FAMILY);
-    tables = this.admin.listTables();
-    assertEquals(numTables + 1, tables.length);
-    LOG.info("created table = " + tableName);
-    return ht;
-  }
-
-
-  @org.junit.Rule
-  public org.apache.hadoop.hbase.ResourceCheckerJUnitRule cu =
-    new org.apache.hadoop.hbase.ResourceCheckerJUnitRule();
-}
-
-
-

src/test/java/org/apache/hadoop/hbase/client/TestInstantSchemaChangeSplit.java

@@ -1,224 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.hadoop.hbase.client;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
-
-import java.io.IOException;
-import java.util.List;
-
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-import org.apache.hadoop.hbase.HColumnDescriptor;
-import org.apache.hadoop.hbase.HConstants;
-import org.apache.hadoop.hbase.HTableDescriptor;
-import org.apache.hadoop.hbase.LargeTests;
-import org.apache.hadoop.hbase.io.hfile.Compression;
-import org.apache.hadoop.hbase.regionserver.HRegion;
-import org.apache.hadoop.hbase.regionserver.HRegionServer;
-import org.apache.hadoop.hbase.util.Bytes;
-import org.apache.hadoop.hbase.zookeeper.MasterSchemaChangeTracker;
-import org.apache.zookeeper.KeeperException;
-import org.junit.Test;
-import org.junit.experimental.categories.Category;
-
-@Category(LargeTests.class)
-public class TestInstantSchemaChangeSplit extends InstantSchemaChangeTestBase {
-
-  final Log LOG = LogFactory.getLog(getClass());
-
-  /**
-   * The objective of the following test is to validate that schema exclusions happen properly.
-   * When a RS server dies or crashes(?) mid-flight during a schema refresh, we would exclude
-   * all online regions in that RS, as well as the RS itself from schema change process.
-   *
-   * @throws IOException
-   * @throws KeeperException
-   * @throws InterruptedException
-   */
-  @Test
-  public void testInstantSchemaChangeExclusions() throws IOException,
-      KeeperException, InterruptedException {
-    MasterSchemaChangeTracker msct =
-    TEST_UTIL.getHBaseCluster().getMaster().getSchemaChangeTracker();
-    LOG.info("Start testInstantSchemaChangeExclusions() ");
-    String tableName = "testInstantSchemaChangeExclusions";
-    HTable ht = createTableAndValidate(tableName);
-
-    HColumnDescriptor hcd = new HColumnDescriptor(HConstants.CATALOG_FAMILY);
-    hcd.setMaxVersions(99);
-    hcd.setBlockCacheEnabled(false);
-
-    HRegionServer hrs = findRSWithOnlineRegionFor(tableName);
-    //miniHBaseCluster.getRegionServer(0).abort("killed for test");
-    admin.modifyColumn(Bytes.toBytes(tableName), hcd);
-    hrs.abort("Aborting for tests");
-    hrs.getSchemaChangeTracker().setSleepTimeMillis(20000);
-
-    //admin.modifyColumn(Bytes.toBytes(tableName), hcd);
-    LOG.debug("Waiting for Schema Change process to complete");
-    waitForSchemaChangeProcess(tableName, 15000);
-    assertEquals(msct.doesSchemaChangeNodeExists(tableName), false);
-    // Sleep for some time so that our region is reassigned to some other RS
-    // by master.
-    Thread.sleep(10000);
-    List<HRegion> onlineRegions
-        = miniHBaseCluster.getRegions(Bytes.toBytes("testInstantSchemaChangeExclusions"));
-    assertTrue(!onlineRegions.isEmpty());
-    for (HRegion onlineRegion : onlineRegions) {
-      HTableDescriptor htd = onlineRegion.getTableDesc();
-      HColumnDescriptor tableHcd = htd.getFamily(HConstants.CATALOG_FAMILY);
-      assertTrue(tableHcd.isBlockCacheEnabled() == false);
-      assertEquals(tableHcd.getMaxVersions(), 99);
-    }
-    LOG.info("End testInstantSchemaChangeExclusions() ");
-    ht.close();
- }
-
-  /**
-   * This test validates that when a schema change request fails on the
-   * RS side, we appropriately register the failure in the Master Schema change
-   * tracker's node as well as capture the error cause.
-   *
-   * Currently an alter request fails if RS fails with an IO exception say due to
-   * missing or incorrect codec. With instant schema change the same failure happens
-   * and we register the failure with associated cause and also update the
-   * monitor status appropriately.
-   *
-   * The region(s) will be orphaned in both the cases.
-   *
-   */
-  @Test
-  public void testInstantSchemaChangeWhileRSOpenRegionFailure() throws IOException,
-      KeeperException, InterruptedException {
-    MasterSchemaChangeTracker msct =
-    TEST_UTIL.getHBaseCluster().getMaster().getSchemaChangeTracker();
-
-    LOG.info("Start testInstantSchemaChangeWhileRSOpenRegionFailure() ");
-    String tableName = "testInstantSchemaChangeWhileRSOpenRegionFailure";
-    HTable ht = createTableAndValidate(tableName);
-
-    // create now 100 regions
-    TEST_UTIL.createMultiRegions(conf, ht,
-      HConstants.CATALOG_FAMILY, 10);
-
-    // wait for all the regions to be assigned
-    Thread.sleep(10000);
-    List<HRegion> onlineRegions
-        = miniHBaseCluster.getRegions(
-        Bytes.toBytes("testInstantSchemaChangeWhileRSOpenRegionFailure"));
-    int size = onlineRegions.size();
-    // we will not have any online regions
-    LOG.info("Size of online regions = " + onlineRegions.size());
-
-    HColumnDescriptor hcd = new HColumnDescriptor(HConstants.CATALOG_FAMILY);
-    hcd.setMaxVersions(99);
-    hcd.setBlockCacheEnabled(false);
-    hcd.setCompressionType(Compression.Algorithm.SNAPPY);
-
-    admin.modifyColumn(Bytes.toBytes(tableName), hcd);
-    Thread.sleep(100);
-
-    assertEquals(msct.doesSchemaChangeNodeExists(tableName), true);
-    Thread.sleep(10000);
-    // get the current alter status and validate that its failure with appropriate error msg.
-    MasterSchemaChangeTracker.MasterAlterStatus mas = msct.getMasterAlterStatus(tableName);
-    assertTrue(mas != null);
-    assertEquals(mas.getCurrentAlterStatus(),
-        MasterSchemaChangeTracker.MasterAlterStatus.AlterState.FAILURE);
-    assertTrue(mas.getErrorCause() != null);
-    LOG.info("End testInstantSchemaChangeWhileRSOpenRegionFailure() ");
-    ht.close();
- }
-
-  @Test
-  public void testConcurrentInstantSchemaChangeAndSplit() throws IOException,
-  InterruptedException, KeeperException {
-    final String tableName = "testConcurrentInstantSchemaChangeAndSplit";
-    conf = TEST_UTIL.getConfiguration();
-    LOG.info("Start testConcurrentInstantSchemaChangeAndSplit()");
-    final String newFamily = "newFamily";
-    HTable ht = createTableAndValidate(tableName);
-    final MasterSchemaChangeTracker msct =
-      TEST_UTIL.getHBaseCluster().getMaster().getSchemaChangeTracker();
-
-    // create now 10 regions
-    TEST_UTIL.createMultiRegions(conf, ht,
-        HConstants.CATALOG_FAMILY, 4);
-    int rowCount = TEST_UTIL.loadTable(ht, HConstants.CATALOG_FAMILY);
-    //assertRowCount(t, rowCount);
-
-    Runnable splitter = new Runnable() {
-      public void run() {
-        // run the splits now.
-        try {
-          LOG.info("Splitting table now ");
-          admin.split(Bytes.toBytes(tableName));
-        } catch (IOException e) {
-          e.printStackTrace();
-        } catch (InterruptedException e) {
-          e.printStackTrace();
-        }
-      }
-    };
-
-    Runnable schemaChanger = new Runnable() {
-      public void run() {
-        HColumnDescriptor hcd = new HColumnDescriptor(newFamily);
-        try {
-          admin.addColumn(Bytes.toBytes(tableName), hcd);
-        } catch (IOException ioe) {
-          ioe.printStackTrace();
-
-        }
-      }
-    };
-    schemaChanger.run();
-    Thread.sleep(50);
-    splitter.run();
-    waitForSchemaChangeProcess(tableName, 40000);
-
-    Put put1 = new Put(row);
-    put1.add(Bytes.toBytes(newFamily), qualifier, value);
-    LOG.info("******** Put into new column family ");
-    ht.put(put1);
-    ht.flushCommits();
-
-    LOG.info("******** Get from new column family ");
-    Get get1 = new Get(row);
-    get1.addColumn(Bytes.toBytes(newFamily), qualifier);
-    Result r = ht.get(get1);
-    byte[] tvalue = r.getValue(Bytes.toBytes(newFamily), qualifier);
-    LOG.info(" Value put = " + value + " value from table = " + tvalue);
-    int result = Bytes.compareTo(value, tvalue);
-    assertEquals(result, 0);
-    LOG.info("End testConcurrentInstantSchemaChangeAndSplit() ");
-    ht.close();
-  }
-      
-
-
-  @org.junit.Rule
-  public org.apache.hadoop.hbase.ResourceCheckerJUnitRule cu =
-    new org.apache.hadoop.hbase.ResourceCheckerJUnitRule();
-}
-
-
-

src/test/java/org/apache/hadoop/hbase/master/MockRegionServer.java

@@ -360,6 +360,12 @@ class MockRegionServer implements HRegionInterface, RegionServerServices {
     return null;
   }
 
+  @Override
+  public List<HRegion> getOnlineRegions(byte[] tableName) throws IOException {
+    // TODO Auto-generated method stub
+    return null;
+  }
+
   @Override
   public HServerInfo getHServerInfo() throws IOException {
     // TODO Auto-generated method stub
@@ -513,17 +519,6 @@ class MockRegionServer implements HRegionInterface, RegionServerServices {
     return null;
   }
 
-  @Override
-  public List<HRegion> getOnlineRegions(byte[] tableName) throws IOException {
-    // TODO Auto-generated method stub
-    return null;
-  }
-
-  @Override
-  public void refreshRegion(HRegion hRegion) throws IOException {
-    // TODO Auto-generated method stub
-  }
-
   @Override
   public Configuration getConfiguration() {
     return this.conf;

src/test/java/org/apache/hadoop/hbase/master/TestCatalogJanitor.java

@@ -51,15 +51,12 @@ import org.apache.hadoop.hbase.client.HConnection;
 import org.apache.hadoop.hbase.client.HConnectionManager;
 import org.apache.hadoop.hbase.client.HConnectionTestingUtility;
 import org.apache.hadoop.hbase.client.Result;
-import org.apache.hadoop.hbase.executor.EventHandler;
 import org.apache.hadoop.hbase.executor.ExecutorService;
 import org.apache.hadoop.hbase.io.Reference;
 import org.apache.hadoop.hbase.ipc.HRegionInterface;
 import org.apache.hadoop.hbase.regionserver.Store;
 import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.hadoop.hbase.util.Writables;
-import org.apache.hadoop.hbase.zookeeper.MasterSchemaChangeTracker;
-import org.apache.hadoop.hbase.zookeeper.RegionServerTracker;
 import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
 import org.junit.Test;
 import org.junit.experimental.categories.Category;
@@ -155,6 +152,11 @@ public class TestCatalogJanitor {
       this.asm = Mockito.mock(AssignmentManager.class);
     }
 
+    @Override
+    public void checkTableModifiable(byte[] tableName) throws IOException {
+      //no-op
+    }
+
     @Override
     public void createTable(HTableDescriptor desc, byte[][] splitKeys)
         throws IOException {
@@ -171,11 +173,6 @@ public class TestCatalogJanitor {
       return null;
     }
 
-    public void checkTableModifiable(byte[] tableName,
-                                     EventHandler.EventType eventType)
-        throws IOException {
-    }
-
     @Override
     public MasterFileSystem getMasterFileSystem() {
       return this.mfs;
@@ -263,14 +260,6 @@ public class TestCatalogJanitor {
       };
     }
 
-    public MasterSchemaChangeTracker getSchemaChangeTracker() {
-      return null;
-    }
-
-    public RegionServerTracker getRegionServerTracker() {
-      return null;
-    }
-
     @Override
     public boolean isServerShutdownHandlerEnabled() {
       return true;

src/test/java/org/apache/hadoop/hbase/util/MockRegionServerServices.java

@@ -63,9 +63,6 @@ public class MockRegionServerServices implements RegionServerServices {
     return null;
   }
 
-  public void refreshRegion(HRegion hRegion) throws IOException {
-  }
-
   @Override
   public void addToOnlineRegions(HRegion r) {
     this.regions.put(r.getRegionInfo().getEncodedName(), r);