Index: src/java/org/apache/lucene/index/SegmentReader.java
===================================================================
--- src/java/org/apache/lucene/index/SegmentReader.java	(revision 786482)
+++ src/java/org/apache/lucene/index/SegmentReader.java	(working copy)
@@ -475,6 +475,17 @@
     return instance;
   }
 
+  synchronized void openDocStores(SegmentReader orig) throws IOException {
+    if (fieldsReaderOrig == null) {
+      orig.openDocStores();
+      
+      fieldsReaderOrig = orig.fieldsReaderOrig;
+      termVectorsReaderOrig = orig.termVectorsReaderOrig;
+      storeCFSReader = orig.storeCFSReader;
+      cfsReader = orig.cfsReader;
+    }
+  }
+
   synchronized void openDocStores() throws IOException {
     if (fieldsReaderOrig == null) {
       final Directory storeDir;
Index: src/java/org/apache/lucene/index/MergePolicy.java
===================================================================
--- src/java/org/apache/lucene/index/MergePolicy.java	(revision 786482)
+++ src/java/org/apache/lucene/index/MergePolicy.java	(working copy)
@@ -133,6 +133,9 @@
         b.append(" into ").append(info.name);
       if (optimize)
         b.append(" [optimize]");
+      if (mergeDocStores) {
+        b.append(" [mergeDocStores]");
+      }
       return b.toString();
     }
   }
Index: src/java/org/apache/lucene/index/IndexWriter.java
===================================================================
--- src/java/org/apache/lucene/index/IndexWriter.java	(revision 786482)
+++ src/java/org/apache/lucene/index/IndexWriter.java	(working copy)
@@ -4829,7 +4829,7 @@
         }
 
         for(int i=0;i<numSegments;i++) {
-          merge.readersClone[i].openDocStores();
+          merge.readersClone[i].openDocStores(merge.readers[i]);
         }
 
         // Clear DSS