HBASE-7741 Don't use bulk assigner if assigning just several regions

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1443617 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -157,6 +157,18 @@ public class AssignmentManager extends ZooKeeperListener {
 
   private final RegionStates regionStates;
 
+  // The threshold to use bulk assigning. Using bulk assignment
+  // only if assigning at least this many regions to at least this
+  // many servers. If assigning fewer regions to fewer servers,
+  // bulk assigning may be not as efficient.
+  private final int bulkAssignThresholdRegions;
+  private final int bulkAssignThresholdServers;
+
+  // Should bulk assignment wait till all regions are assigned,
+  // or it is timed out?  This is useful to measure bulk assignment
+  // performance, but not needed in most use cases.
+  private final boolean bulkAssignWaitTillAllAssigned;
+
   /**
    * Indicator that AssignmentManager has recovered the region states so
    * that ServerShutdownHandler can be fully enabled and re-assign regions
@@ -206,6 +218,11 @@ public class AssignmentManager extends ZooKeeperListener {
     this.metricsMaster = metricsMaster;// can be null only with tests.
     this.regionStates = new RegionStates(server, serverManager);
 
+    this.bulkAssignWaitTillAllAssigned =
+      conf.getBoolean("hbase.bulk.assignment.waittillallassigned", false);
+    this.bulkAssignThresholdRegions = conf.getInt("hbase.bulk.assignment.threshold.regions", 7);
+    this.bulkAssignThresholdServers = conf.getInt("hbase.bulk.assignment.threshold.servers", 3);
+
     int workers = conf.getInt("hbase.assignment.zkevent.workers", 20);
     ThreadFactory threadFactory = Threads.newDaemonThreadFactory("hbase-am-zkevent-worker");
     zkEventWorkers = Threads.getBoundedCachedThreadPool(workers, 60L,
@@ -2115,11 +2132,8 @@ public class AssignmentManager extends ZooKeeperListener {
     Map<ServerName, List<HRegionInfo>> bulkPlan =
       balancer.retainAssignment(regions, servers);
 
-    LOG.info("Bulk assigning " + regions.size() + " region(s) across " +
-      servers.size() + " server(s), retainAssignment=true");
-    BulkAssigner ba = new GeneralBulkAssigner(this.server, bulkPlan, this);
-    ba.bulkAssign();
-    LOG.info("Bulk assigning done");
+    assign(regions.size(), servers.size(),
+      "retainAssignment=true", bulkPlan);
   }
 
   /**
@@ -2135,6 +2149,7 @@ public class AssignmentManager extends ZooKeeperListener {
     if (regions == null || regions.isEmpty()) {
       return;
     }
+
     List<ServerName> servers = serverManager.createDestinationServersList();
     if (servers == null || servers.isEmpty()) {
       throw new IOException("Found no destination server to assign region(s)");
@@ -2144,14 +2159,37 @@ public class AssignmentManager extends ZooKeeperListener {
     Map<ServerName, List<HRegionInfo>> bulkPlan
       = balancer.roundRobinAssignment(regions, servers);
 
-    LOG.info("Bulk assigning " + regions.size() + " region(s) round-robin across "
-      + servers.size() + " server(s)");
+    assign(regions.size(), servers.size(),
+      "round-robin=true", bulkPlan);
+  }
+
+  private void assign(int regions, int totalServers,
+      String message, Map<ServerName, List<HRegionInfo>> bulkPlan)
+          throws InterruptedException, IOException {
+
+    int servers = bulkPlan.size();
+    if (servers == 1 || (regions < bulkAssignThresholdRegions
+        && servers < bulkAssignThresholdServers)) {
+
+      // Not use bulk assignment.  This could be more efficient in small
+      // cluster, especially mini cluster for testing, so that tests won't time out
+      LOG.info("Not use bulk assigning since we are assigning only "
+        + regions + " region(s) to " + servers + " server(s)");
+
+      for (Map.Entry<ServerName, List<HRegionInfo>> plan: bulkPlan.entrySet()) {
+        assign(plan.getKey(), plan.getValue());
+      }
+    } else {
+      LOG.info("Bulk assigning " + regions + " region(s) across "
+        + totalServers + " server(s), " + message);
 
       // Use fixed count thread pool assigning.
-    BulkAssigner ba = new GeneralBulkAssigner(this.server, bulkPlan, this);
+      BulkAssigner ba = new GeneralBulkAssigner(
+        this.server, bulkPlan, this, bulkAssignWaitTillAllAssigned);
       ba.bulkAssign();
       LOG.info("Bulk assigning done");
     }
+  }
 
   /**
    * Assigns all user regions, if any exist.  Used during cluster startup.

hbase-server/src/main/java/org/apache/hadoop/hbase/master/GeneralBulkAssigner.java

@@ -50,13 +50,15 @@ public class GeneralBulkAssigner extends BulkAssigner {
 
   final Map<ServerName, List<HRegionInfo>> bulkPlan;
   final AssignmentManager assignmentManager;
+  final boolean waitTillAllAssigned;
 
   GeneralBulkAssigner(final Server server,
       final Map<ServerName, List<HRegionInfo>> bulkPlan,
-      final AssignmentManager am) {
+      final AssignmentManager am, final boolean waitTillAllAssigned) {
     super(server);
     this.bulkPlan = bulkPlan;
     this.assignmentManager = am;
+    this.waitTillAllAssigned = waitTillAllAssigned;
   }
 
   @Override
@@ -133,6 +135,10 @@ public class GeneralBulkAssigner extends BulkAssigner {
           regionInfoIterator.remove();
         }
       }
+      if (!waitTillAllAssigned) {
+        // No need to wait, let assignment going on asynchronously
+        break;
+      }
       if (!regionSet.isEmpty()) {
         regionStates.waitForUpdate(100);
       }
@@ -142,7 +148,7 @@ public class GeneralBulkAssigner extends BulkAssigner {
       long elapsedTime = System.currentTimeMillis() - startTime;
       String status = "successfully";
       if (!regionSet.isEmpty()) {
-        status = "with " + regionSet.size() + " regions still not assigned yet";
+        status = "with " + regionSet.size() + " regions still in transition";
       }
       LOG.debug("bulk assigning total " + regionCount + " regions to "
         + serverCount + " servers, took " + elapsedTime + "ms, " + status);