From e7195a2e3cbc4124f6bde8c281199e7a1e87089d Mon Sep 17 00:00:00 2001
From: jxiang <jxiang@unknown>
Date: Mon, 16 Sep 2013 23:05:30 +0000
Subject: [PATCH] HBASE-9525 "Move" region right after a region split is
 dangerous

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1523832 13f79535-47bb-0310-9956-ffa450edef68
---
 .../hadoop/hbase/master/AssignmentManager.java       |  9 ++++++++-
 .../TestRegionMergeTransactionOnCluster.java         | 12 +++++++++---
 .../regionserver/TestSplitTransactionOnCluster.java  | 12 +++++++++---
 3 files changed, 26 insertions(+), 7 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 5c1905ef9f4..b594cba6526 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
@@ -2295,6 +2295,13 @@ public class AssignmentManager extends ZooKeeperListener {
     RegionState state = regionStates.getRegionTransitionState(encodedName);
     try {
       if (state == null) {
+        // Region is not in transition.
+        // We can unassign it only if it's not SPLIT/MERGED.
+        state = regionStates.getRegionState(encodedName);
+        if (state.isMerged() || state.isSplit()) {
+          LOG.info("Attempting to unassign " + state + ", ignored");
+          return;
+        }
         // Create the znode in CLOSING state
         try {
           state = regionStates.getRegionState(region);
@@ -2307,7 +2314,7 @@ public class AssignmentManager extends ZooKeeperListener {
           versionOfClosingNode = ZKAssign.createNodeClosing(
             watcher, region, state.getServerName());
           if (versionOfClosingNode == -1) {
-            LOG.debug("Attempting to unassign " +
+            LOG.info("Attempting to unassign " +
                 region.getRegionNameAsString() + " but ZK closing node "
                 + "can't be created.");
             return;
diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestRegionMergeTransactionOnCluster.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestRegionMergeTransactionOnCluster.java
index f54889857c4..aac801ea177 100644
--- a/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestRegionMergeTransactionOnCluster.java
+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestRegionMergeTransactionOnCluster.java
@@ -140,9 +140,15 @@ public class TestRegionMergeTransactionOnCluster {
 
     // We should not be able to assign it again
     am.assign(hri, true, true);
-    assertFalse("Merged region should not be in transition again",
-      regionStates.isRegionInTransition(hri)
-        && regionStates.isRegionInState(hri, State.MERGED));
+    assertFalse("Merged region can't be assigned",
+      regionStates.isRegionInTransition(hri));
+    assertTrue(regionStates.isRegionInState(hri, State.MERGED));
+
+    // We should not be able to unassign it either
+    am.unassign(hri, true, null);
+    assertFalse("Merged region can't be unassigned",
+      regionStates.isRegionInTransition(hri));
+    assertTrue(regionStates.isRegionInState(hri, State.MERGED));
 
     table.close();
   }
diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestSplitTransactionOnCluster.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestSplitTransactionOnCluster.java
index f035b67ddd3..dfd1bf723b5 100644
--- a/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestSplitTransactionOnCluster.java
+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestSplitTransactionOnCluster.java
@@ -850,9 +850,15 @@ public class TestSplitTransactionOnCluster {
 
       // We should not be able to assign it again
       am.assign(hri, true, true);
-      assertFalse("Split region should not be in transition again",
-        regionStates.isRegionInTransition(hri)
-          && regionStates.isRegionInState(hri, State.SPLIT));
+      assertFalse("Split region can't be assigned",
+        regionStates.isRegionInTransition(hri));
+      assertTrue(regionStates.isRegionInState(hri, State.SPLIT));
+
+      // We should not be able to unassign it either
+      am.unassign(hri, true, null);
+      assertFalse("Split region can't be unassigned",
+        regionStates.isRegionInTransition(hri));
+      assertTrue(regionStates.isRegionInState(hri, State.SPLIT));
     } finally {
       admin.setBalancerRunning(true, false);
       cluster.getMaster().setCatalogJanitorEnabled(true);