diff --git a/sql-plugin/src/main/scala/com/nvidia/spark/rapids/GpuColumnarBatchSerializer.scala b/sql-plugin/src/main/scala/com/nvidia/spark/rapids/GpuColumnarBatchSerializer.scala
index 82f368936a7..c9d4fbe0ba7 100644
--- a/sql-plugin/src/main/scala/com/nvidia/spark/rapids/GpuColumnarBatchSerializer.scala
+++ b/sql-plugin/src/main/scala/com/nvidia/spark/rapids/GpuColumnarBatchSerializer.scala
@@ -132,9 +132,12 @@ class SerializedBatchIterator(dIn: DataInputStream, deserTime: GpuMetric)
 class GpuColumnarBatchSerializer(metrics: Map[String, GpuMetric], dataTypes: Array[DataType],
     useKudo: Boolean)
   extends Serializer with Serializable {
+
+  private lazy val kudo = new KudoSerializer(GpuColumnVector.from(dataTypes))
+
   override def newInstance(): SerializerInstance = {
     if (useKudo) {
-      new KudoSerializerInstance(metrics, dataTypes)
+      new KudoSerializerInstance(metrics, dataTypes, kudo)
     } else {
       new GpuColumnarBatchSerializerInstance(metrics)
     }
@@ -158,7 +161,7 @@ private class GpuColumnarBatchSerializerInstance(metrics: Map[String, GpuMetric]
       val batch = value.asInstanceOf[ColumnarBatch]
       val numColumns = batch.numCols()
       val columns: Array[HostColumnVector] = new Array(numColumns)
-      val toClose = new ArrayBuffer[AutoCloseable]()
+      val toClose = new ArrayBuffer[AutoCloseable](numColumns)
       try {
         var startRow = 0
         val numRows = batch.numRows()
@@ -338,7 +341,9 @@ object SerializedTableColumn {
  */
 private class KudoSerializerInstance(
     val metrics: Map[String, GpuMetric],
-    val dataTypes: Array[DataType]) extends SerializerInstance {
+    val dataTypes: Array[DataType],
+    val kudo: KudoSerializer
+) extends SerializerInstance {
   private val dataSize = metrics(METRIC_DATA_SIZE)
   private val serTime = metrics(METRIC_SHUFFLE_SER_STREAM_TIME)
   private val serCalcHeaderTime = metrics(METRIC_SHUFFLE_SER_CALC_HEADER_TIME)
@@ -346,8 +351,6 @@ private class KudoSerializerInstance(
   private val serCopyBufferTime = metrics(METRIC_SHUFFLE_SER_COPY_BUFFER_TIME)
   private val deserTime = metrics(METRIC_SHUFFLE_DESER_STREAM_TIME)
 
-  private lazy val kudo = new KudoSerializer(GpuColumnVector.from(dataTypes))
-
   override def serializeStream(out: OutputStream): SerializationStream = new SerializationStream {
     private[this] val dOut: DataOutputStream =
       new DataOutputStream(new BufferedOutputStream(out))
@@ -356,7 +359,7 @@ private class KudoSerializerInstance(
       val batch = value.asInstanceOf[ColumnarBatch]
       val numColumns = batch.numCols()
       val columns: Array[HostColumnVector] = new Array(numColumns)
-      withResource(new ArrayBuffer[AutoCloseable]()) { toClose =>
+      withResource(new ArrayBuffer[AutoCloseable](numColumns)) { toClose =>
         var startRow = 0
         val numRows = batch.numRows()
         if (batch.numCols() > 0) {
diff --git a/sql-plugin/src/main/scala/com/nvidia/spark/rapids/GpuShuffleCoalesceExec.scala b/sql-plugin/src/main/scala/com/nvidia/spark/rapids/GpuShuffleCoalesceExec.scala
index c33c19cdd8a..62b8e36be65 100644
--- a/sql-plugin/src/main/scala/com/nvidia/spark/rapids/GpuShuffleCoalesceExec.scala
+++ b/sql-plugin/src/main/scala/com/nvidia/spark/rapids/GpuShuffleCoalesceExec.scala
@@ -237,6 +237,7 @@ class KudoTableOperator(
     kudoMergeHeaderTime: GpuMetric,
     kudoMergeBufferTime: GpuMetric) extends SerializedTableOperator[KudoSerializedTableColumn] {
   require(kudo != null, "kudo serializer should not be null")
+  private val kudoTables = new util.ArrayList[KudoTable]()
 
   override def getDataLen(column: KudoSerializedTableColumn): Long = column.kudoTable.getHeader
     .getTotalDataLen
@@ -251,7 +252,8 @@ class KudoTableOperator(
       val totalRowsNum = columns.map(getNumRows).sum
       RowCountOnlyMergeResult(totalRowsNum)
     } else {
-      val kudoTables = new util.ArrayList[KudoTable](columns.length)
+      kudoTables.clear()
+      kudoTables.ensureCapacity(columns.length)
       columns.foreach { column =>
         kudoTables.add(column.kudoTable)
       }