HBASE-1169 When a shutdown is requested, stop scanning META regions immediately

git-svn-id: https://svn.apache.org/repos/asf/hadoop/hbase/trunk@751172 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -39,6 +39,7 @@ Release 0.20.0 - Unreleased
                to compact when loaded with hundreds of regions
    HBASE-1247  checkAndSave doesn't Write Ahead Log
    HBASE-1243  oldlogfile.dat is screwed, so is it's region
+   HBASE-1169  When a shutdown is requested, stop scanning META regions immediately
 
   IMPROVEMENTS
    HBASE-1089  Add count of regions on filesystem to master UI; add percentage

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

@@ -95,8 +95,8 @@ public class HMaster extends Thread implements HConstants, HMasterInterface,
   
   static final Log LOG = LogFactory.getLog(HMaster.class.getName());
 
-  public long getProtocolVersion(String protocol,
-      long clientVersion) {
+  public long getProtocolVersion(@SuppressWarnings("unused") String protocol,
+      @SuppressWarnings("unused") long clientVersion) {
     return HBaseRPCProtocolVersion.versionID;
   }
 
@@ -105,7 +105,7 @@ public class HMaster extends Thread implements HConstants, HMasterInterface,
   // started here in HMaster rather than have them have to know about the
   // hosting class
   volatile AtomicBoolean closed = new AtomicBoolean(true);
-  volatile boolean shutdownRequested = false;
+  volatile AtomicBoolean shutdownRequested = new AtomicBoolean(false);
   volatile boolean fsOk = true;
   final Path rootdir;
   private final HBaseConfiguration conf;
@@ -337,7 +337,7 @@ public class HMaster extends Thread implements HConstants, HMasterInterface,
    */
   public HServerAddress getRootRegionLocation() {
     HServerAddress rootServer = null;
-    if (!shutdownRequested && !closed.get()) {
+    if (!shutdownRequested.get() && !closed.get()) {
       rootServer = regionManager.getRootRegionLocation();
     }
     return rootServer;
@@ -367,9 +367,14 @@ public class HMaster extends Thread implements HConstants, HMasterInterface,
     try {
       while (!closed.get()) {
         // check if we should be shutting down
-        if (shutdownRequested && serverManager.numServers() == 0) {
-          startShutdown();
-          break;
+        if (shutdownRequested.get()) {
+          // The region servers won't all exit until we stop scanning the
+          // meta regions
+          regionManager.stopScanners();
+          if (serverManager.numServers() == 0) {
+            startShutdown();
+            break;
+          }
         }
         // work on the TodoQueue. If that fails, we should shut down.
         if (!processToDoQueue()) {
@@ -380,8 +385,6 @@ public class HMaster extends Thread implements HConstants, HMasterInterface,
       LOG.fatal("Unhandled exception. Starting shutdown.", t);
       closed.set(true);
     }
-    // The region servers won't all exit until we stop scanning the meta regions
-    regionManager.stopScanners();
     
     // Wait for all the remaining region servers to report in.
     serverManager.letRegionServersShutdown();
@@ -593,7 +596,7 @@ public class HMaster extends Thread implements HConstants, HMasterInterface,
 
   public void shutdown() {
     LOG.info("Cluster shutdown requested. Starting to quiesce servers");
-    this.shutdownRequested = true;
+    this.shutdownRequested.set(true);
   }
 
   public void createTable(HTableDescriptor desc)
@@ -958,7 +961,7 @@ public class HMaster extends Thread implements HConstants, HMasterInterface,
   
   /**
    * Get the ZK wrapper object
-   * @return
+   * @return the zookeeper wrapper
    */
   public ZooKeeperWrapper getZooKeeperWrapper() {
     return zooKeeperWrapper;

src/java/org/apache/hadoop/hbase/master/MetaScanner.java

@@ -51,7 +51,7 @@ class MetaScanner extends BaseScanner {
    * @param master
    */
   public MetaScanner(HMaster master) {
-    super(master, false, master.metaRescanInterval, master.closed);
+    super(master, false, master.metaRescanInterval, master.shutdownRequested);
   }
 
   // Don't retry if we get an error while scanning. Errors are most often

src/java/org/apache/hadoop/hbase/master/RegionManager.java

@@ -132,7 +132,7 @@ class RegionManager implements HConstants {
   private final int zooKeeperNumRetries;
   private final int zooKeeperPause;
 
-  RegionManager(HMaster master) throws IOException {
+  RegionManager(HMaster master) {
     HBaseConfiguration conf = master.getConfiguration();
 
     this.master = master;
@@ -169,7 +169,7 @@ class RegionManager implements HConstants {
   
   void reassignRootRegion() {
     unsetRootRegion();
-    if (!master.shutdownRequested) {
+    if (!master.shutdownRequested.get()) {
       synchronized (regionsInTransition) {
         RegionState s = new RegionState(HRegionInfo.ROOT_REGIONINFO);
         s.setUnassigned();
@@ -1014,10 +1014,8 @@ class RegionManager implements HConstants {
   /**
    * Set the root region location.
    * @param address Address of the region server where the root lives
-   * @throws IOException If there's a problem connection to ZooKeeper.
    */
-  public void setRootRegionLocation(HServerAddress address)
-  throws IOException {
+  public void setRootRegionLocation(HServerAddress address) {
     writeRootRegionLocationToZooKeeper(address);
 
     synchronized (rootRegionLocation) {

src/java/org/apache/hadoop/hbase/master/RootScanner.java

@@ -31,7 +31,7 @@ class RootScanner extends BaseScanner {
    * @param master
    */
   public RootScanner(HMaster master) {
-    super(master, true, master.metaRescanInterval, master.closed);
+    super(master, true, master.metaRescanInterval, master.shutdownRequested);
   }
 
   /**

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

@@ -116,7 +116,6 @@ class ServerManager implements HConstants {
    * them or the server is shutting down.
    */
   private boolean checkForGhostReferences(final HServerInfo serverInfo) {
-    String s = serverInfo.getServerAddress().toString().trim();
     boolean result = false;
     for (long sleepTime = -1; !master.closed.get() && !result;) {
       if (sleepTime != -1) {
@@ -225,7 +224,7 @@ class ServerManager implements HConstants {
       }
     }
 
-    if (master.shutdownRequested) {
+    if (master.shutdownRequested.get()) {
       if(quiescedServers.get() >= serversToServerInfo.size()) {
         // If the only servers we know about are meta servers, then we can
         // proceed with shutdown