ETT capacity issues

Resolving The Problem

Since each occurrence must be assigned a unique INPUT ARRIVAL TIME between the CURRENT TIME and the END OF THE CURRENT PLAN, and since OPC INPUT ARRIVAL TIMES have a granularity of one minute, no more occurrences of a given application may be added to the CURRENT PLAN than there are minutes between the current time and the end of the CP. If an attempt to add a new occurrence into the CP will cause this limit to be exceeded, message EQQM952E is issued. Thus, at any given time, the number of occurrences of an application that can be added to the CP is equal to the number of minutes until the CP END TIME.

There is one additional limit. The MAXIMUM TOTAL NUMBER OF OCCURRENCES OF ALL
APPLICATIONS IN THE CURRENT PLAN is set by the MAXOCCNUM() options of the BATCHOPT and JTOPTS initialization statements. If an attempt to add a new occurrence to the CURRENT PLAN results in this limit being exceeded, message EQQM172E is issued.

SOLUTION:
1. For either message, running a CP REPLAN or a CP EXTEND will remove COMPLETED occurrences of all applications from the CURRENT PLAN. This should make room for NEW occurrences to be added.

2. Further, setting BATCHOPT initialization statement parameter PREVRES(NO) will cause completed occurrences to be removed more promptly enabling full utilization up to the limits listed above. If PREVRES() is set (or allowed to default) to YES, the actual working limits will be much less. The following is a summary of PREVRES() function and how it relates to ETT.

When PREVRES() is set (or allowed to default) to YES, OPC CP EXTEND and REPLAN batch processing proceeds as follows:

a. All occurrences in the CURRENT PLAN which have RETAINED FOR REPORTING status are copied to the work files from which the DAILY PLAN REPORTS are generated.
b. All RETAINED FOR REPORTING occurrences are deleted from the CP.
c. All occurrences in COMPLETE status are flagged as RETAINED FOR REPORTING.

"RETAINED FOR REPORTING" occurrences cannot be viewed via the OPC dialogs, but the occurrences occupy "slots" in the current plan dataset and thus decrease the number of those slots which are available for "new" work.

When PREVRES() is set to NO, CP EXTEND AND REPLAN batch processing proceed as follows:
a. All COMPLETED completed occurrences in the CURRENT PLAN are copied to the work files from which the DAILY PLAN REPORTS are generated.
b. All COMPLETED occurrences are then DELETED from the CURRENT PLAN.

With PREVRES(NO), the "retained for reporting" status does not exist.

The intended purpose of PREVRES(YES) is to make it possible for a user to run one "extra" CURRENT PLAN EXTEND or CURRENT PLAN REPLAN batch job within a 24-hour period, and still have the DAILY PLAN REPORTS cover the complete 24-hours. However as explained here, this enhanced reporting comes at the expense of ETT and overall capacity.