How can I improve the performance by using the XNATIVE modes and VTRead in VTOOL? Does XNATIVE mode change the data structure when I write?
The VTRead function in VTOOL is a different thing and has nothing to do with XNATIVE! XNATIVE mode does not change the data stored in a VB/ISAM DataSet. It only affects the way you look at the data. If a record is read using XNATIVE, it is read from the DataSet and the data is returned as a pointer to a data buffer containing the raw DataSet record. This saves the software from decoding all fields it into a Type structure. This is always the way VsamEx reads data. This is much faster even if you need to look at a lot of fields. The key here is that you only unpack the field’s that you need. In writing the XNATIVE record, we do not perform the encode function because what you are passing is a native VB/ISAM or VsamEx record. The tradeoff is that, for larger records, this saves the decode/encode translation which may involve allocating memory and other overhead. Additionally, in Visual Basic, another language layer will translate this structure even further, adding to a potentially signi
