diff --git a/core/src/main/scala/com/intel/oap/expression/ColumnarSortMergeJoin.scala b/core/src/main/scala/com/intel/oap/expression/ColumnarSortMergeJoin.scala
index 8f4bdb1eb..8009d05a7 100644
--- a/core/src/main/scala/com/intel/oap/expression/ColumnarSortMergeJoin.scala
+++ b/core/src/main/scala/com/intel/oap/expression/ColumnarSortMergeJoin.scala
@@ -109,7 +109,6 @@ class ColumnarSortMergeJoin(
       }
       build_cb = realbuildIter.next()
       val beforeBuild = System.nanoTime()
-        // handle projection
         val projectedBuildKeyCols: List[ArrowWritableColumnVector] = if (buildProjector != null) {
           val builderOrdinalList = buildProjector.getOrdinalList
           val builderAttributes = buildProjector.output
@@ -124,8 +123,9 @@ class ColumnarSortMergeJoin(
           build_cb.column(i).asInstanceOf[ArrowWritableColumnVector]) ::: projectedBuildKeyCols
         val build_rb =
           ConverterUtils.createArrowRecordBatch(build_cb.numRows, buildCols.map(_.getValueVector))
-      (0 until build_cb.numCols).toList.foreach(i =>
-        build_cb.column(i).asInstanceOf[ArrowWritableColumnVector].retain())
+
+      (0 until buildCols.size).toList.foreach(i =>
+        buildCols(i).retain())
       inputBatchHolder += build_cb
       prober.evaluate(build_rb)
       prepareTime += NANOSECONDS.toMillis(System.nanoTime() - beforeBuild)
@@ -167,7 +167,7 @@ class ColumnarSortMergeJoin(
         val cb = realstreamIter.next()
         last_cb = cb
         val beforeJoin = System.nanoTime()
-        val stream_rb: ArrowRecordBatch = ConverterUtils.createArrowRecordBatch(cb)
+        
         val output_rb = if (cb.numRows > 0) {
           val projectedStreamKeyCols: List[ArrowWritableColumnVector] =
             if (streamProjector != null) {