From 14f80913e55d6994398aab8cfc80ceab4d348887 Mon Sep 17 00:00:00 2001
From: ramkrishna <ramkrishna@unknown>
Date: Fri, 20 Apr 2012 17:36:02 +0000
Subject: [PATCH] HBASE-5809 Avoid move api to take the destination server same
 as the source server. (Rajesh)

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1328458 13f79535-47bb-0310-9956-ffa450edef68
---
 .../apache/hadoop/hbase/master/HMaster.java    |  5 +++++
 .../apache/hadoop/hbase/client/TestAdmin.java  | 18 ++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/src/main/java/org/apache/hadoop/hbase/master/HMaster.java b/src/main/java/org/apache/hadoop/hbase/master/HMaster.java
index 7a66a02d841..d47b83a0187 100644
--- a/src/main/java/org/apache/hadoop/hbase/master/HMaster.java
+++ b/src/main/java/org/apache/hadoop/hbase/master/HMaster.java
@@ -1174,6 +1174,11 @@ Server {
       this.assignmentManager.unassign(hri);
     } else {
       dest = new ServerName(Bytes.toString(destServerName));
+      if (dest.equals(p.getSecond())) {
+        LOG.debug("Skipping move of region " + hri.getRegionNameAsString()
+            + " because region already assigned to the same server " + dest +".");
+        return;
+      }
       try {
         if (this.cpHost != null) {
           if (this.cpHost.preMove(p.getFirst(), p.getSecond(), dest)) {
diff --git a/src/test/java/org/apache/hadoop/hbase/client/TestAdmin.java b/src/test/java/org/apache/hadoop/hbase/client/TestAdmin.java
index aa7f51bff38..804dfdeeed5 100644
--- a/src/test/java/org/apache/hadoop/hbase/client/TestAdmin.java
+++ b/src/test/java/org/apache/hadoop/hbase/client/TestAdmin.java
@@ -43,6 +43,8 @@ import org.apache.hadoop.hbase.*;
 import org.apache.hadoop.hbase.executor.EventHandler;
 import org.apache.hadoop.hbase.executor.EventHandler.EventType;
 import org.apache.hadoop.hbase.executor.ExecutorService;
+import org.apache.hadoop.hbase.master.AssignmentManager;
+import org.apache.hadoop.hbase.master.HMaster;
 import org.apache.hadoop.hbase.master.MasterServices;
 import org.apache.hadoop.hbase.regionserver.HRegion;
 import org.apache.hadoop.hbase.regionserver.HRegionServer;
@@ -1404,6 +1406,22 @@ public class TestAdmin {
     assertTrue(("actual count: " + count), count <= 2);
   }
 
+  @Test
+  public void testMoveToPreviouslyAssignedRS() throws IOException {
+    byte[] tableName = Bytes.toBytes("testMoveToPreviouslyAssignedRS");
+    MiniHBaseCluster cluster = TEST_UTIL.getHBaseCluster();
+    HMaster master = cluster.getMaster();
+    HBaseAdmin localAdmin = createTable(tableName);
+    List<HRegionInfo> tableRegions = localAdmin.getTableRegions(tableName);
+    HRegionInfo hri = tableRegions.get(0);
+    AssignmentManager am = master.getAssignmentManager();
+    ServerName server = am.getRegionServerOfRegion(hri);
+    localAdmin.move(hri.getEncodedNameAsBytes(), Bytes.toBytes(server.getServerName()));
+    assertEquals("Current region server and region server before move should be same.", server,
+        am.getRegionServerOfRegion(hri));
+  }
+
+
   private void setUpforLogRolling() {
     // Force a region split after every 768KB
     TEST_UTIL.getConfiguration().setLong(HConstants.HREGION_MAX_FILESIZE,