Index: src/java/org/apache/lucene/index/FieldsReader.java
===================================================================
--- src/java/org/apache/lucene/index/FieldsReader.java	(revision 591357)
+++ src/java/org/apache/lucene/index/FieldsReader.java	(working copy)
@@ -186,6 +186,27 @@
     return doc;
   }
 
+  final int length(int docID) throws IOException {
+    indexStream.seek((docID + docStoreOffset) * 8L);
+    final long pos1 = indexStream.readLong();
+    // nocommit: do this w/o exception -- check file length
+    long pos2;
+    try {
+      pos2 = indexStream.readLong();
+    } catch (IOException e) {
+      pos2 = fieldsStream.length();
+    }
+    return (int) (pos2 - pos1);
+  }
+
+  final void doc(int docID, byte[] buffer, int size) throws CorruptIndexException, IOException {
+    indexStream.seek((docID + docStoreOffset) * 8L);
+    final long pos = indexStream.readLong();
+    //final long size = length(docID);
+    fieldsStream.seek(pos);
+    fieldsStream.readBytes(buffer, 0, size);
+  }
+
   /**
    * Skip the field.  We still have to read some of the information about the field, but can skip past the actual content.
    * This will have the most payoff on large fields.
Index: src/java/org/apache/lucene/index/FieldsWriter.java
===================================================================
--- src/java/org/apache/lucene/index/FieldsWriter.java	(revision 591357)
+++ src/java/org/apache/lucene/index/FieldsWriter.java	(working copy)
@@ -127,6 +127,12 @@
       }
     }
 
+    // Bulk write of full entry for a document
+    final void addDocument(byte[] buffer, int size) throws IOException {
+      indexStream.writeLong(fieldsStream.getFilePointer());
+      fieldsStream.writeBytes(buffer, size);
+    }
+
     final void addDocument(Document doc) throws IOException {
         indexStream.writeLong(fieldsStream.getFilePointer());
 
Index: src/java/org/apache/lucene/index/SegmentMerger.java
===================================================================
--- src/java/org/apache/lucene/index/SegmentMerger.java	(revision 591357)
+++ src/java/org/apache/lucene/index/SegmentMerger.java	(working copy)
@@ -210,24 +210,50 @@
       fieldInfos = new FieldInfos();		  // merge field names
     }
 
-    int docCount = 0;
     for (int i = 0; i < readers.size(); i++) {
       IndexReader reader = (IndexReader) readers.elementAt(i);
-      addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.TERMVECTOR_WITH_POSITION_OFFSET), true, true, true, false);
-      addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.TERMVECTOR_WITH_POSITION), true, true, false, false);
-      addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.TERMVECTOR_WITH_OFFSET), true, false, true, false);
-      addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.TERMVECTOR), true, false, false, false);
-      addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.STORES_PAYLOADS), false, false, false, true);
-      addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.INDEXED), false, false, false, false);
-      fieldInfos.add(reader.getFieldNames(IndexReader.FieldOption.UNINDEXED), false);
+      if (reader instanceof SegmentReader) {
+        SegmentReader sreader = (SegmentReader) reader;
+        for (int j = 0; j < sreader.getFieldInfos().size(); j++) {
+          FieldInfo fi = sreader.getFieldInfos().fieldInfo(j);
+          fieldInfos.add(fi.name, fi.isIndexed, fi.storeTermVector, fi.storePositionWithTermVector, fi.storeOffsetWithTermVector, !reader.hasNorms(fi.name));
+        }
+      } else {
+        addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.TERMVECTOR_WITH_POSITION_OFFSET), true, true, true, false);
+        addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.TERMVECTOR_WITH_POSITION), true, true, false, false);
+        addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.TERMVECTOR_WITH_OFFSET), true, false, true, false);
+        addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.TERMVECTOR), true, false, false, false);
+        addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.STORES_PAYLOADS), false, false, false, true);
+        addIndexed(reader, fieldInfos, reader.getFieldNames(IndexReader.FieldOption.INDEXED), false, false, false, false);
+        fieldInfos.add(reader.getFieldNames(IndexReader.FieldOption.UNINDEXED), false);
+      }
     }
+
     fieldInfos.write(directory, segment + ".fnm");
 
+    int docCount = 0;
+
     if (mergeDocStores) {
 
-      FieldsWriter fieldsWriter = // merge field values
-        new FieldsWriter(directory, segment, fieldInfos);
-    
+      SegmentReader[] sreaders = new SegmentReader[readers.size()];
+      for (int i = 0; i < readers.size(); i++) {
+        IndexReader reader = (IndexReader) readers.elementAt(i);
+        boolean same = reader.getFieldNames(IndexReader.FieldOption.ALL).size() == fieldInfos.size() && reader instanceof SegmentReader;
+        if (same) {
+          SegmentReader sreader = (SegmentReader) reader;
+          for (int j = 0; same && j < fieldInfos.size(); j++) {
+            same = fieldInfos.fieldName(j).equals(sreader.getFieldInfos().fieldName(j));
+          }
+          if(same)
+            sreaders[i] = sreader;
+        }
+      }
+	
+      byte[] buffer = new byte[1024];
+
+      // merge field values
+      FieldsWriter fieldsWriter = new FieldsWriter(directory, segment, fieldInfos);
+
       // for merging we don't want to compress/uncompress the data, so to tell the FieldsReader that we're
       // in  merge mode, we use this FieldSelector
       FieldSelector fieldSelectorMerge = new FieldSelector() {
@@ -239,17 +265,27 @@
       try {
         for (int i = 0; i < readers.size(); i++) {
           IndexReader reader = (IndexReader) readers.elementAt(i);
+          SegmentReader sreader = sreaders[i];
           int maxDoc = reader.maxDoc();
           for (int j = 0; j < maxDoc; j++)
-            if (!reader.isDeleted(j)) {               // skip deleted docs
-              fieldsWriter.addDocument(reader.document(j, fieldSelectorMerge));
+            if (!reader.isDeleted(j)) { // skip deleted docs
+              if (sreader != null) {
+                int len = sreader.getFieldsReader().length(j);
+                if (len > buffer.length) {
+                  buffer = new byte[len * 2];
+                }
+                //System.out.println("direct copy " + len);
+                sreader.getFieldsReader().doc(j, buffer, len);
+                fieldsWriter.addDocument(buffer, len);
+              } else {
+                fieldsWriter.addDocument(reader.document(j, fieldSelectorMerge));
+              }
               docCount++;
             }
         }
       } finally {
         fieldsWriter.close();
       }
-
     } else
       // If we are skipping the doc stores, that means there
       // are no deletions in any of these segments, so we
Index: src/java/org/apache/lucene/index/SegmentReader.java
===================================================================
--- src/java/org/apache/lucene/index/SegmentReader.java	(revision 591357)
+++ src/java/org/apache/lucene/index/SegmentReader.java	(working copy)
@@ -314,6 +314,10 @@
     undeleteAll = false;
   }
 
+  FieldsReader getFieldsReader() {
+    return fieldsReader;
+  }
+
   protected void doClose() throws IOException {
     if (fieldsReader != null) {
       fieldsReader.close();
@@ -388,6 +392,10 @@
     return tis.terms(t);
   }
 
+  FieldInfos getFieldInfos() {
+    return fieldInfos;
+  }
+
   /**
    * @throws CorruptIndexException if the index is corrupt
    * @throws IOException if there is a low-level IO error