Index: src/core/org/terrier/indexing/hadoop/Hadoop_BasicSinglePassIndexer.java
===================================================================
--- src/core/org/terrier/indexing/hadoop/Hadoop_BasicSinglePassIndexer.java	(revision 3776)
+++ src/core/org/terrier/indexing/hadoop/Hadoop_BasicSinglePassIndexer.java	(working copy)
@@ -112,6 +112,9 @@
 	implements Mapper<Text, SplitAwareWrapper<Document>, SplitEmittedTerm, MapEmittedPostingList>,
 	Reducer<SplitEmittedTerm, MapEmittedPostingList, Object, Object>
 {
+	
+	public static final boolean RESET_IDS_ON_FLUSH = false;
+	
 	/**
 	 * main
 	 * @param args
@@ -311,6 +314,7 @@
 			value="DM_GC",
 			justification="Forcing GC is an essential part of releasing" +
 					"memory for further indexing")
+	@Override
 	/** causes the posting lists built up in memory to be flushed out */
 	protected void forceFlush() throws IOException
 	{
@@ -325,9 +329,10 @@
 		createMemoryPostings();
 		memoryCheck.reset();
 		numberOfDocsSinceFlush = 0;
-		currentId = 0;
+		if (RESET_IDS_ON_FLUSH)
+			currentId = 0;
 		flushNo++;
-	}	
+	}
 	
 	/**
 	 * Map processes a single document. Stores the terms in the document along with the posting list
Index: src/core/org/terrier/structures/indexing/singlepass/hadoop/HadoopRunsMerger.java
===================================================================
--- src/core/org/terrier/structures/indexing/singlepass/hadoop/HadoopRunsMerger.java	(revision 3776)
+++ src/core/org/terrier/structures/indexing/singlepass/hadoop/HadoopRunsMerger.java	(working copy)
@@ -31,6 +31,7 @@
 import java.util.LinkedList;
 import java.util.ListIterator;
 
+import org.terrier.indexing.hadoop.Hadoop_BasicSinglePassIndexer;
 import org.terrier.structures.BasicLexiconEntry;
 import org.terrier.structures.LexiconEntry;
 import org.terrier.structures.LexiconOutputStream;
@@ -94,7 +95,7 @@
 		byte startBitOffset = this.getBitOffset();
 		LexiconEntry le = null;
 		// for each run in the list 
-		int counter = 0;
+		//int counter = 0;
 		//for one term: for each set of postings for that term
 		while (run.hasNext()) {
 			PostingInRun posting = run.next();
@@ -113,7 +114,7 @@
 				posting.addToLexiconEntry(le);
 			lastFreq += posting.getTF();
 			lastDocFreq += posting.getDf();
-			counter++;
+			//counter++;
 		}
 		le.setTermId(currentTerm++);
 		((BasicLexiconEntry)le).setOffset(startOffset, startBitOffset);
@@ -155,18 +156,22 @@
 		if (correctHRD == null)
 			throw new IOException("Did not find map data for split "+ splitNo);
 		
-		// Add the FlushShift
 		int currentFlushDocs=0;
-		ListIterator<Integer> LI = correctHRD.getFlushDocSizes().listIterator(0);
-		//System.out.println("Runs Flush number : "+run.getRunNo()+", Size of HRD :"+correctHRD.getFlushDocSizes().size());
-		int currentFlush =0;
-		while (currentFlush<flushNumber) {
-			//System.out.println("Runs Flush number : "+run.getRunNo()+", FlushCheck : "+currentFlush+", Size of HRD :"+correctHRD.getFlushDocSizes().size());
-			currentFlushDocs += LI.next(); 
-			currentFlush++;
+		// Add the FlushShift, if configured to do so 
+		if (Hadoop_BasicSinglePassIndexer.RESET_IDS_ON_FLUSH)
+		{		
+			
+			ListIterator<Integer> LI = correctHRD.getFlushDocSizes().listIterator(0);
+			//System.out.println("Runs Flush number : "+run.getRunNo()+", Size of HRD :"+correctHRD.getFlushDocSizes().size());
+			int currentFlush =0;
+			while (currentFlush<flushNumber) {
+				//System.out.println("Runs Flush number : "+run.getRunNo()+", FlushCheck : "+currentFlush+", Size of HRD :"+correctHRD.getFlushDocSizes().size());
+				currentFlushDocs += LI.next(); 
+				currentFlush++;
+			}		
 		}
+		return NumPreDocs+currentFlushDocs;
 		
-		return NumPreDocs+currentFlushDocs;
 	}
 
 }