Index: src/java/org/apache/lucene/index/IndexWriter.java
===================================================================
--- src/java/org/apache/lucene/index/IndexWriter.java	(revision 178062)
+++ src/java/org/apache/lucene/index/IndexWriter.java	(working copy)
@@ -121,6 +121,7 @@
   private SegmentInfos segmentInfos = new SegmentInfos(); // the segments
   private final Directory ramDirectory = new RAMDirectory(); // for temp segs
 
+  private long bufferedDocCount = 0;
   private Lock writeLock;
 
   private int termIndexInterval = DEFAULT_TERM_INDEX_INTERVAL;
@@ -462,6 +463,7 @@
     dw.addDocument(segmentName, doc);
     synchronized (this) {
       segmentInfos.addElement(new SegmentInfo(segmentName, 1, ramDirectory));
+      bufferedDocCount++;
       maybeMergeSegments();
     }
   }
@@ -629,6 +631,15 @@
 
   /** Incremental segment merger.  */
   private final void maybeMergeSegments() throws IOException {
+    /**
+     *  do not bother checking the segment details to determine
+     *  if we should merge, but instead honour the maxBufferedDocs(minMergeDocs)
+     *  property to ensure we do not spend time checking for merge conditions
+     *  
+     */
+    if(bufferedDocCount<minMergeDocs) {
+        return;
+    }
     long targetMergeDocs = minMergeDocs;
     while (targetMergeDocs <= maxMergeDocs) {
       // find segments smaller than current target size
@@ -648,6 +659,7 @@
 
       targetMergeDocs *= mergeFactor;		  // increase target size
     }
+
   }
 
   /** Pops segments off of segmentInfos stack down to minSegment, merges them,
@@ -672,6 +684,8 @@
 
     int mergedDocCount = merger.merge();
 
+    bufferedDocCount -= mergedDocCount; // update bookkeeping about how many docs we have buffered
+    
     if (infoStream != null) {
       infoStream.println(" into "+mergedName+" ("+mergedDocCount+" docs)");
     }