TRANSFER Programming Manual

Communicating with TISERV
Designing and Writing a Client
9–14 069138, Update 1 to 040970 Tandem Computers Incorporated
Communicating
with TISERV
Once your request is ready, you send it to the TRANSFER interactive server class
(TISERV).
TRANSFER server use is slightly different from that of general PATHWAY servers. A
general rule for PATHWAY applications is to design server classes so that each
request sent to each server takes approximately the same amount of time. When you
direct UOWs to TISERV, however, you do not send individual requests; you send
groups of UOWs.
It is difficult to estimate the time required to handle groups of UOWs, but you do have
flexibility in balancing the workload per request among servers. One possible
approach to this situation might be to define several server classes, with each class
using the same server program but having different response-time characteristics.
Coding Guidelines The following subsections discuss the following:
SCREEN COBOL coding guidelines
COBOL coding guidelines
Debugging techniques
SCREEN COBOL
Guidelines
Guidelines for coding SCREEN COBOL programs operating in a PATHWAY
environment appear in the PATHWAY SCREEN COBOL Reference Manual and the
PATHWAY Application Programmer's Guide. Guidelines for coding programs in
COBOL, FORTRAN, or TAL (which do not run under PATHWAY) appear in the
manuals covering those languages. The following additional rules apply specifically
to programs that are TRANSFER clients:
Always abort any transaction if the PW-REPLY-CODE field in the IPC header is
set to a value greater than 1 (indicating an error in the IPC header or in an
individual UOW). Doing this will retain the consistency of your database and
make it easier to debug your application and get it running again.
When coding a client, mistakes creating inconsistencies between the amount of
buffer space provided for a reply in an IPC and the actual length of the data
returned are not uncommon. You can trap this kind of error by including an ON-
ERROR clause in each SEND statement that transmits UOWs.
To help conserve working storage, some UOWs are set up so that you can use the
response from one as the request portion in another. For example, you can use the
response to the GET-PROFILE-ELEM UOW as a request in the ALTER-PROFILE-
ELEM UOW. Similarly, you can use the response from the GET-AGENT-SELECT
UOW as a request in the ALTER-AGENT-SELECT UOW.
To minimize message processing time, you can group UOWs in the same SEND
operation to TISERV. You can group UOWs together when
None of the UOWs needs information returned from any of the others
Each UOW has a separate working storage area