diff --git a/indexing-hadoop/src/main/java/io/druid/indexer/IndexGeneratorJob.java b/indexing-hadoop/src/main/java/io/druid/indexer/IndexGeneratorJob.java
index 3980c18de56..bc8ca44dd33 100644
--- a/indexing-hadoop/src/main/java/io/druid/indexer/IndexGeneratorJob.java
+++ b/indexing-hadoop/src/main/java/io/druid/indexer/IndexGeneratorJob.java
@@ -33,6 +33,7 @@ import com.metamx.common.IAE;
 import com.metamx.common.ISE;
 import com.metamx.common.guava.CloseQuietly;
 import com.metamx.common.logger.Logger;
+import io.druid.collections.StupidPool;
 import io.druid.data.input.InputRow;
 import io.druid.data.input.impl.StringInputRowParser;
 import io.druid.offheap.OffheapBufferPool;
@@ -324,8 +325,12 @@ public class IndexGeneratorJob implements Jobby
 
       final Interval interval = config.getGranularitySpec().bucketInterval(bucket.time).get();
       final AggregatorFactory[] aggs = config.getSchema().getDataSchema().getAggregators();
+      final int maxTotalBufferSize = config.getSchema().getTuningConfig().getBufferSize();
+      final int aggregationBufferSize = (int) ((double) maxTotalBufferSize
+                                               * config.getSchema().getTuningConfig().getAggregationBufferRatio());
 
-      IncrementalIndex index = makeIncrementalIndex(bucket, aggs);
+      final StupidPool<ByteBuffer> bufferPool = new OffheapBufferPool(aggregationBufferSize);
+      IncrementalIndex index = makeIncrementalIndex(bucket, aggs, bufferPool);
       try {
         File baseFlushFile = File.createTempFile("base", "flush");
         baseFlushFile.delete();
@@ -363,9 +368,9 @@ public class IndexGeneratorJob implements Jobby
 
             context.progress();
             persist(index, interval, file, progressIndicator);
-            // close this index and make a new one
+            // close this index and make a new one, reusing same buffer
             index.close();
-            index = makeIncrementalIndex(bucket, aggs);
+            index = makeIncrementalIndex(bucket, aggs, bufferPool);
 
             startTime = System.currentTimeMillis();
             ++indexCount;
@@ -630,7 +635,7 @@ public class IndexGeneratorJob implements Jobby
       return numRead;
     }
 
-    private IncrementalIndex makeIncrementalIndex(Bucket theBucket, AggregatorFactory[] aggs)
+    private IncrementalIndex makeIncrementalIndex(Bucket theBucket, AggregatorFactory[] aggs, StupidPool bufferPool)
     {
       final HadoopTuningConfig tuningConfig = config.getSchema().getTuningConfig();
       final IncrementalIndexSchema indexSchema = new IncrementalIndexSchema.Builder()
@@ -640,14 +645,12 @@ public class IndexGeneratorJob implements Jobby
           .withMetrics(aggs)
           .build();
       if (tuningConfig.isIngestOffheap()) {
-        final int maxTotalBufferSize = tuningConfig.getBufferSize();
-        final int aggregationBufferSize = (int) ((double) maxTotalBufferSize
-                                                 * tuningConfig.getAggregationBufferRatio());
+
         return new OffheapIncrementalIndex(
             indexSchema,
-            new OffheapBufferPool(aggregationBufferSize),
+            bufferPool,
             true,
-            maxTotalBufferSize
+            tuningConfig.getBufferSize()
         );
       } else {
         return new OnheapIncrementalIndex(