From 289c12dea3cf66500feb1b62f64c45b3838fdadc Mon Sep 17 00:00:00 2001
From: larsh <larsh@unknown>
Date: Tue, 15 Jan 2013 22:14:23 +0000
Subject: [PATCH] HBASE-7551 nodeChildrenChange event may happen after the
 transition to RS_ZK_REGION_SPLITTING in SplitTransaction causing the SPLIT
 event to be missed in the master side. (Ram, Ted, and Lars H)

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1433696 13f79535-47bb-0310-9956-ffa450edef68
---
 .../hbase/master/AssignmentManager.java       | 22 +++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/AssignmentManager.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/AssignmentManager.java
index 5d8d836e4b1..ca1f25eb399 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/AssignmentManager.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/AssignmentManager.java
@@ -21,7 +21,6 @@ package org.apache.hadoop.hbase.master;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -40,7 +39,6 @@ import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
 
-import com.google.common.collect.LinkedHashMultimap;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.classification.InterfaceAudience;
@@ -85,6 +83,8 @@ import org.apache.zookeeper.KeeperException.NoNodeException;
 import org.apache.zookeeper.KeeperException.NodeExistsException;
 import org.apache.zookeeper.data.Stat;
 
+import com.google.common.collect.LinkedHashMultimap;
+
 /**
  * Manages and performs region assignment.
  * <p>
@@ -1061,13 +1061,27 @@ public class AssignmentManager extends ZooKeeperListener {
               ZKUtil.listChildrenAndWatchForNewChildren(
                 watcher, watcher.assignmentZNode);
             if (children != null) {
+              Stat stat = new Stat();
               for (String child : children) {
                 // if region is in transition, we already have a watch
                 // on it, so no need to watch it again. So, as I know for now,
                 // this is needed to watch splitting nodes only.
                 if (!regionStates.isRegionInTransition(child)) {
-                  ZKUtil.watchAndCheckExists(watcher,
-                    ZKUtil.joinZNode(watcher.assignmentZNode, child));
+                  stat.setVersion(0);
+                  byte[] data = ZKAssign.getDataAndWatch(watcher,
+                    ZKUtil.joinZNode(watcher.assignmentZNode, child), stat);
+                  if (data != null && stat.getVersion() > 0) {
+                    try {
+                      RegionTransition rt = RegionTransition.parseFrom(data);
+
+                      //See HBASE-7551, handle splitting too, in case we miss the node change event
+                      if (rt.getEventType() == EventType.RS_ZK_REGION_SPLITTING) {
+                        handleRegion(rt, stat.getVersion());
+                      }
+                    } catch (DeserializationException de) {
+                      LOG.error("error getting data for " + child, de);
+                    }
+                  }
                 }
               }
             }