diff --git a/src/org/apache/cassandra/db/EfficientBidiMap.java b/src/org/apache/cassandra/db/EfficientBidiMap.java
index 616de5e105..cba957c378 100644
--- a/src/org/apache/cassandra/db/EfficientBidiMap.java
+++ b/src/org/apache/cassandra/db/EfficientBidiMap.java
@@ -19,10 +19,14 @@
 package org.apache.cassandra.db;
 
 import java.io.Serializable;
-import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentSkipListSet;
+import java.util.Map;
+import java.util.SortedSet;
+import java.util.Comparator;
+import java.util.TreeSet;
 
 import org.apache.cassandra.db.ColumnComparatorFactory.ComparatorType;
-import org.apache.cassandra.service.StorageService;
 
 
 /**
@@ -31,19 +35,13 @@ import org.apache.cassandra.service.StorageService;
 
 class EfficientBidiMap implements Serializable
 {
-    private Map<String, IColumn> map_ = new HashMap<String, IColumn>();
+    private Map<String, IColumn> map_;
     private SortedSet<IColumn> sortedSet_;
     private Comparator<IColumn> columnComparator_;
 
-    EfficientBidiMap()
-    {
-    	this(ColumnComparatorFactory.getComparator(ComparatorType.TIMESTAMP));
-    }
-
     EfficientBidiMap(Comparator<IColumn> columnComparator)
     {
-    	columnComparator_ = columnComparator;
-    	sortedSet_ = new TreeSet<IColumn>(columnComparator);
+        this(new ConcurrentHashMap<String, IColumn>(), new ConcurrentSkipListSet<IColumn>(columnComparator), columnComparator);
     }
 
     EfficientBidiMap(Map<String, IColumn> map, SortedSet<IColumn> set, Comparator<IColumn> comparator)
@@ -53,18 +51,6 @@ class EfficientBidiMap implements Serializable
     	columnComparator_ = comparator;
     }
 
-    EfficientBidiMap(Object[] objects, Comparator<IColumn> columnComparator)
-    {
-    	columnComparator_ = columnComparator;
-    	sortedSet_ = new TreeSet<IColumn>(columnComparator);
-        for ( Object object : objects )
-        {
-            IColumn column = (IColumn)object;
-            sortedSet_.add(column);
-            map_.put(column.name(), column);
-        }
-    }
-
     public Comparator<IColumn> getComparator()
     {
     	return columnComparator_;
@@ -116,8 +102,8 @@ class EfficientBidiMap implements Serializable
 
     EfficientBidiMap cloneMe()
     {
-    	Map<String, IColumn> map = new HashMap<String, IColumn>(map_);
-    	SortedSet<IColumn> set = new TreeSet<IColumn>(sortedSet_);
+    	Map<String, IColumn> map = new ConcurrentHashMap<String, IColumn>(map_);
+    	SortedSet<IColumn> set = new ConcurrentSkipListSet<IColumn>(sortedSet_);
     	return new EfficientBidiMap(map, set, columnComparator_);
     }
 }