diff --git a/native-sql-engine/core/src/main/scala/com/intel/oap/execution/ArrowRowToColumnarExec.scala b/native-sql-engine/core/src/main/scala/com/intel/oap/execution/ArrowRowToColumnarExec.scala
index a32ae1f69..87f7de1fe 100644
--- a/native-sql-engine/core/src/main/scala/com/intel/oap/execution/ArrowRowToColumnarExec.scala
+++ b/native-sql-engine/core/src/main/scala/com/intel/oap/execution/ArrowRowToColumnarExec.scala
@@ -166,8 +166,10 @@ case class ArrowRowToColumnarExec(child: SparkPlan) extends UnaryExecNode {
                 val unsafeRow = row.asInstanceOf[UnsafeRow]
                 val sizeInBytes = unsafeRow.getSizeInBytes
                 if ((offset + sizeInBytes) > arrowBuf.capacity()) {
+                  val tmpBuf = allocator.buffer(((offset + sizeInBytes) * 1.5).toLong)
+                  tmpBuf.setBytes(0, arrowBuf, 0, offset)
                   arrowBuf.close()
-                  arrowBuf = allocator.buffer((arrowBuf.capacity() * 1.2).toLong)
+                  arrowBuf = tmpBuf
                 }
                 Platform.copyMemory(unsafeRow.getBaseObject, unsafeRow.getBaseOffset,
                   null, arrowBuf.memoryAddress() + offset, sizeInBytes)
@@ -192,7 +194,7 @@ case class ArrowRowToColumnarExec(child: SparkPlan) extends UnaryExecNode {
               processTime.set(NANOSECONDS.toMillis(elapse))
               last_cb
             } else {
-              logInfo("the buffer allocated failed and will fall back to non arrow optimization")
+              logInfo("not unsaferow, fallback to java based r2c")
               val vectors: Seq[WritableColumnVector] =
                 ArrowWritableColumnVector.allocateColumns(numRows, schema)
               var rowCount = 0
diff --git a/native-sql-engine/core/src/test/scala/org/apache/spark/sql/execution/SortSuite.scala b/native-sql-engine/core/src/test/scala/org/apache/spark/sql/execution/SortSuite.scala
index 6a4f3f626..b2dd9aac0 100644
--- a/native-sql-engine/core/src/test/scala/org/apache/spark/sql/execution/SortSuite.scala
+++ b/native-sql-engine/core/src/test/scala/org/apache/spark/sql/execution/SortSuite.scala
@@ -32,6 +32,12 @@ import org.apache.spark.sql.types._
 class SortSuite extends SparkPlanTest with SharedSparkSession {
   import testImplicits.newProductEncoder
   import testImplicits.localSeqToDatasetHolder
+  
+  override protected def sparkConf: SparkConf = {
+    val conf = super.sparkConf
+    conf.set("spark.memory.offHeap.size", String.valueOf("5000m"))
+    .set("spark.sql.inMemoryColumnarStorage.batchSize", "100")
+  }
 
   test("basic sorting using ExternalSort") {