Newer databases are being defined with fields or rows greater than 32767 bytes; as a result, applications will need to support larger parcel sizes. Therefore, we recommend that the Maximum Parcel option be set to H for all future applications, thus indicating that the application can support parcel sizes greater than 32767 bytes.
The logic of the application is not affected, only certain uses of signed two-byte unsigned integers. Because values greater than 32767 exceed the capacity of such integers on IBM mainframes, applications must insure that any value that is based on parcel length must use longer integers or unsigned integers. If this is not done, CLIv2 could return a length that could be considered to be a negative value, with unpredictable results.
Since the maximum value that can be contained in the two-byte length is 65535, requests with larger lengths cannot use Variable‑length‑request. Responses with Variable‑length‑fetch that require larger lengths will be rejected.
Because PL/I does not support unsigned integers, you cannot use the Variable Length Request option to allow the PL/I VARYING attribute for the Request Pointer or the Using Data Pointer for requests greater than 32767. This same consideration also applies to use of the Variable Length Fetch option and the Fetch Data pointer.
When using Move Mode, you may need to increase the Fetch Maximum Data Length to accommodate the larger parcels.