diff --git a/sql/core/src/main/java/org/apache/spark/sql/execution/vectorized/OffHeapColumnVector.java b/sql/core/src/main/java/org/apache/spark/sql/execution/vectorized/OffHeapColumnVector.java
index e988c0722bd72..a7d3744d00e91 100644
--- a/sql/core/src/main/java/org/apache/spark/sql/execution/vectorized/OffHeapColumnVector.java
+++ b/sql/core/src/main/java/org/apache/spark/sql/execution/vectorized/OffHeapColumnVector.java
@@ -436,28 +436,29 @@ public void loadBytes(ColumnVector.Array array) {
   // Split out the slow path.
   @Override
   protected void reserveInternal(int newCapacity) {
+    int oldCapacity = (this.data == 0L) ? 0 : capacity;
     if (this.resultArray != null) {
       this.lengthData =
-          Platform.reallocateMemory(lengthData, elementsAppended * 4, newCapacity * 4);
+          Platform.reallocateMemory(lengthData, oldCapacity * 4, newCapacity * 4);
       this.offsetData =
-          Platform.reallocateMemory(offsetData, elementsAppended * 4, newCapacity * 4);
+          Platform.reallocateMemory(offsetData, oldCapacity * 4, newCapacity * 4);
     } else if (type instanceof ByteType || type instanceof BooleanType) {
-      this.data = Platform.reallocateMemory(data, elementsAppended, newCapacity);
+      this.data = Platform.reallocateMemory(data, oldCapacity, newCapacity);
     } else if (type instanceof ShortType) {
-      this.data = Platform.reallocateMemory(data, elementsAppended * 2, newCapacity * 2);
+      this.data = Platform.reallocateMemory(data, oldCapacity * 2, newCapacity * 2);
     } else if (type instanceof IntegerType || type instanceof FloatType ||
         type instanceof DateType || DecimalType.is32BitDecimalType(type)) {
-      this.data = Platform.reallocateMemory(data, elementsAppended * 4, newCapacity * 4);
+      this.data = Platform.reallocateMemory(data, oldCapacity * 4, newCapacity * 4);
     } else if (type instanceof LongType || type instanceof DoubleType ||
         DecimalType.is64BitDecimalType(type) || type instanceof TimestampType) {
-      this.data = Platform.reallocateMemory(data, elementsAppended * 8, newCapacity * 8);
+      this.data = Platform.reallocateMemory(data, oldCapacity * 8, newCapacity * 8);
     } else if (resultStruct != null) {
       // Nothing to store.
     } else {
       throw new RuntimeException("Unhandled " + type);
     }
-    this.nulls = Platform.reallocateMemory(nulls, elementsAppended, newCapacity);
-    Platform.setMemory(nulls + elementsAppended, (byte)0, newCapacity - elementsAppended);
+    this.nulls = Platform.reallocateMemory(nulls, oldCapacity, newCapacity);
+    Platform.setMemory(nulls + oldCapacity, (byte)0, newCapacity - oldCapacity);
     capacity = newCapacity;
   }
 }