diff --git a/client-mr/core/src/main/java/org/apache/hadoop/mapred/SortWriteBufferManager.java b/client-mr/core/src/main/java/org/apache/hadoop/mapred/SortWriteBufferManager.java
index ea450619bd..0da7cd9304 100644
--- a/client-mr/core/src/main/java/org/apache/hadoop/mapred/SortWriteBufferManager.java
+++ b/client-mr/core/src/main/java/org/apache/hadoop/mapred/SortWriteBufferManager.java
@@ -239,7 +239,9 @@ private void prepareBufferForSend(List<ShuffleBlockInfo> shuffleBlocks, SortWrit
     if (combinerRunner != null) {
       try {
         buffer = combineBuffer(buffer);
-        LOG.debug("Successfully finished combining.");
+        if (LOG.isDebugEnabled()) {
+          LOG.debug("Successfully finished combining.");
+        }
       } catch (Exception e) {
         LOG.error("Error occurred while combining in Map:", e);
       }
diff --git a/client-mr/core/src/test/java/org/apache/hadoop/mapred/SortWriteBufferManagerTest.java b/client-mr/core/src/test/java/org/apache/hadoop/mapred/SortWriteBufferManagerTest.java
index 929ecf3d18..fbb2803913 100644
--- a/client-mr/core/src/test/java/org/apache/hadoop/mapred/SortWriteBufferManagerTest.java
+++ b/client-mr/core/src/test/java/org/apache/hadoop/mapred/SortWriteBufferManagerTest.java
@@ -366,6 +366,22 @@ public void testCombineBuffer() throws Exception {
         Task.CombinerRunner.create(
             jobConf, new TaskAttemptID(), combineInputCounter, reporter, null);
 
+    SortWriteBuffer<Text, IntWritable> buffer =
+        new SortWriteBuffer<Text, IntWritable>(
+            1, comparator, 10000, keySerializer, valueSerializer);
+
+    List<String> wordTable =
+        Lists.newArrayList(
+            "apple", "banana", "fruit", "cherry", "Chinese", "America", "Japan", "tomato");
+    Random random = new Random();
+    for (int i = 0; i < 8; i++) {
+      buffer.addRecord(new Text(wordTable.get(i)), new IntWritable(1));
+    }
+    for (int i = 0; i < 100; i++) {
+      int index = random.nextInt(wordTable.size());
+      buffer.addRecord(new Text(wordTable.get(index)), new IntWritable(1));
+    }
+
     SortWriteBufferManager<Text, IntWritable> manager =
         new SortWriteBufferManager<Text, IntWritable>(
             10240,
@@ -394,22 +410,6 @@ public void testCombineBuffer() throws Exception {
             new RssConf(),
             combinerRunner);
 
-    SortWriteBuffer<Text, IntWritable> buffer =
-        new SortWriteBuffer<Text, IntWritable>(
-            1, comparator, 10000, keySerializer, valueSerializer);
-
-    List<String> wordTable =
-        Lists.newArrayList(
-            "apple", "banana", "fruit", "cherry", "Chinese", "America", "Japan", "tomato");
-    Random random = new Random();
-    for (int i = 0; i < 8; i++) {
-      buffer.addRecord(new Text(wordTable.get(i)), new IntWritable(1));
-    }
-    for (int i = 0; i < 100; i++) {
-      int index = random.nextInt(wordTable.size());
-      buffer.addRecord(new Text(wordTable.get(index)), new IntWritable(1));
-    }
-
     buffer.sort();
     SortWriteBuffer<Text, IntWritable> newBuffer = manager.combineBuffer(buffer);