update comment

velox/row/UnsafeRowDeserializers.h

@@ -553,14 +553,16 @@ struct UnsafeRowPrimitiveBatchDeserializer {
  */
 struct UnsafeRowDeserializer {
  public:
-  /// If all the column types are primitive type, use the fast deserialization
-  /// which computes the memoryAddress of each row, and set all the data of one
-  /// column at once, otherwise, deserialize row one by one.
-  /// @param memoryAddress the start memory address of the serialized UnsafeRow.
+  /// Deserialize the rows which is serialized in contiguous memory.
+  /// Deserialize fast when all the column types are primitive type, otherwise,
+  /// deserialize rows one by one, as previously. Fast deserialization
+  /// computes the start memoryAddress of one data by the column index and row
+  /// number, and set all the data of one column at once.
+  /// @param memoryAddress the start memory address of the serialized rows .
   /// @param type the element type.
-  /// @param offsets offset of the row deserialized data. It's size should be
+  /// @param offsets offset of each row serialized data. It's size should be
   /// equal to the deserialized rows. First offset is 0.
-  /// @param pool the memory pool to allocate Vectors.
+  /// @param pool the memory pool to allocate Vector.
   static VectorPtr deserialize(
       const uint8_t* memoryAddress,
       const RowTypePtr& type,