diff --git a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/ClassSize.java b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/ClassSize.java
index 710ed6d9844..cb43877f9f2 100644
--- a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/ClassSize.java
+++ b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/ClassSize.java
@@ -103,6 +103,12 @@ public class ClassSize {
   /** Overhead for timerange */
   public static final int TIMERANGE;
 
+  /** Overhead for TimeRangeTracker */
+  public static final int TIMERANGE_TRACKER;
+
+  /** Overhead for KeyValueSkipListSet */
+  public static final int KEYVALUE_SKIPLIST_SET;
+
   /* Are we running on jdk7? */
   private static final boolean JDK7;
   static {
@@ -181,6 +187,10 @@ public class ClassSize {
     COPYONWRITE_ARRAYLIST = align(OBJECT + (2 * REFERENCE) + ARRAY);
 
     TIMERANGE = align(ClassSize.OBJECT + Bytes.SIZEOF_LONG * 2 + Bytes.SIZEOF_BOOLEAN);
+
+    TIMERANGE_TRACKER = align(ClassSize.OBJECT + Bytes.SIZEOF_LONG * 2);
+
+    KEYVALUE_SKIPLIST_SET = align(OBJECT + REFERENCE);
   }
 
   /**
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/KeyValueSkipListSet.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/KeyValueSkipListSet.java
index 4e82880c35f..1297ce297b2 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/KeyValueSkipListSet.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/KeyValueSkipListSet.java
@@ -44,7 +44,7 @@ import java.util.concurrent.ConcurrentSkipListMap;
  * get and set and won't throw ConcurrentModificationException when iterating.
  */
 @InterfaceAudience.Private
-class KeyValueSkipListSet implements NavigableSet<KeyValue> {
+public class KeyValueSkipListSet implements NavigableSet<KeyValue> {
   private final ConcurrentNavigableMap<KeyValue, KeyValue> delegatee;
 
   KeyValueSkipListSet(final KeyValue.KVComparator c) {
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MemStore.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MemStore.java
index 28a1a6acfd4..734140c0ca7 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MemStore.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MemStore.java
@@ -962,8 +962,8 @@ public class MemStore implements HeapSize {
 
   public final static long DEEP_OVERHEAD = ClassSize.align(FIXED_OVERHEAD +
       ClassSize.REENTRANT_LOCK + ClassSize.ATOMIC_LONG +
-      ClassSize.COPYONWRITE_ARRAYSET + ClassSize.COPYONWRITE_ARRAYLIST +
-      (2 * ClassSize.CONCURRENT_SKIPLISTMAP));
+      (2 * ClassSize.TIMERANGE_TRACKER) +
+      (2 * ClassSize.KEYVALUE_SKIPLIST_SET) + (2 * ClassSize.CONCURRENT_SKIPLISTMAP));
 
   /** Used for readability when we don't store memstore timestamp in HFile */
   public static final boolean NO_PERSISTENT_TS = false;
diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/io/TestHeapSize.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/io/TestHeapSize.java
index 7511e99bfea..d4a5ce157de 100644
--- a/hbase-server/src/test/java/org/apache/hadoop/hbase/io/TestHeapSize.java
+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/io/TestHeapSize.java
@@ -47,7 +47,10 @@ import org.apache.hadoop.hbase.io.hfile.CachedBlock;
 import org.apache.hadoop.hbase.io.hfile.LruBlockCache;
 import org.apache.hadoop.hbase.regionserver.HRegion;
 import org.apache.hadoop.hbase.regionserver.HStore;
+import org.apache.hadoop.hbase.regionserver.KeyValueSkipListSet;
 import org.apache.hadoop.hbase.regionserver.MemStore;
+import org.apache.hadoop.hbase.regionserver.MemStoreLAB;
+import org.apache.hadoop.hbase.regionserver.TimeRangeTracker;
 import org.apache.hadoop.hbase.util.ClassSize;
 import org.junit.BeforeClass;
 import org.junit.Test;
@@ -225,7 +228,23 @@ public class TestHeapSize  {
       assertEquals(expected, actual);
     }
 
+    // TimeRangeTracker
+    cl = TimeRangeTracker.class;
+    expected = ClassSize.estimateBase(cl, false);
+    actual = ClassSize.TIMERANGE_TRACKER;
+    if (expected != actual) {
+      ClassSize.estimateBase(cl, true);
+      assertEquals(expected, actual);
+    }
 
+    // KeyValueSkipListSet
+    cl = KeyValueSkipListSet.class;
+    expected = ClassSize.estimateBase(cl, false);
+    actual = ClassSize.KEYVALUE_SKIPLIST_SET;
+    if (expected != actual) {
+      ClassSize.estimateBase(cl, true);
+      assertEquals(expected, actual);
+    }
   }
 
   /**
@@ -288,17 +307,19 @@ public class TestHeapSize  {
     expected = ClassSize.estimateBase(cl, false);
     expected += ClassSize.estimateBase(ReentrantReadWriteLock.class, false);
     expected += ClassSize.estimateBase(AtomicLong.class, false);
-    expected += ClassSize.estimateBase(ConcurrentSkipListMap.class, false);
-    expected += ClassSize.estimateBase(ConcurrentSkipListMap.class, false);
-    expected += ClassSize.estimateBase(CopyOnWriteArraySet.class, false);
-    expected += ClassSize.estimateBase(CopyOnWriteArrayList.class, false);
+    expected += (2 * ClassSize.estimateBase(KeyValueSkipListSet.class, false));
+    expected += (2 * ClassSize.estimateBase(ConcurrentSkipListMap.class, false));
+    expected += (2 * ClassSize.estimateBase(TimeRangeTracker.class, false));
     if(expected != actual) {
       ClassSize.estimateBase(cl, true);
       ClassSize.estimateBase(ReentrantReadWriteLock.class, true);
       ClassSize.estimateBase(AtomicLong.class, true);
+      ClassSize.estimateBase(KeyValueSkipListSet.class, true);
+      ClassSize.estimateBase(KeyValueSkipListSet.class, true);
       ClassSize.estimateBase(ConcurrentSkipListMap.class, true);
-      ClassSize.estimateBase(CopyOnWriteArraySet.class, true);
-      ClassSize.estimateBase(CopyOnWriteArrayList.class, true);
+      ClassSize.estimateBase(ConcurrentSkipListMap.class, true);
+      ClassSize.estimateBase(TimeRangeTracker.class, true);
+      ClassSize.estimateBase(TimeRangeTracker.class, true);
       assertEquals(expected, actual);
     }