Transaction Schedule Types
The APPC/MVS transaction scheduler
lets you assign a schedule type of standard or multi-trans to transaction
programs.
When transaction programs are scheduled as standard (the
default), APPC/MVS initializes them for each inbound conversation
request and terminates them when they finish processing. Standard scheduling
requires that a TP's resources be allocated and deallocated for each inbound
conversation, and isolates TPs from each other and from subsequent requests
for the same transaction program. The standard schedule type provides full
security and basic performance for TPs that are not invoked very frequently
or do not require extensive allocation of resources.
In contrast, the
multi-trans schedule type causes a transaction program to remain
active between inbound conversations, with its resources available. After
each conversation ends, the next calling partner can use the same instance
of the transaction program and avoid the overhead of repeated resource allocation
and deallocation.
Multi-trans TPs run under a shell environment that
is responsible for doing all necessary cleanup to ensure that a TP's conversations
and data are secure for consecutive users. With proper design, multi-trans
scheduling can offer greater performance for transactions that are requested
often by multiple users, that have a high resource overhead, and that finish
processing comparatively quickly.
To use the multi-trans scheduling
option, transaction programs must be defined with a TP schedule type of multi-trans
in the TP profile. For standard scheduling, the TP schedule type can be set
to standard or omitted. For more information, see Using TP Schedule Types.
Note: Multi-trans scheduling is a feature of the APPC/MVS transaction
scheduler. If your transaction program runs under another transaction scheduler
on MVS, multi-trans scheduling is unavailable.