PST= parameter for procedures

Specifies the number of partition specification tables (PST) control blocks to be allocated during system initialization. This number can be between 0 and the number specified on the MAXPST= control region parameter. The default is 0.

Each active dependent region, DBCTL thread, or ODBA thread uses a PST. If additional dependent regions or threads are required during peak periods, IMS dynamically allocates additional PST as the dependent regions or threads are started. PST can be allocated up to the MAXPST value.

During idle periods, the PST are released. The number of PST specified on PST= is maintained. For example, if PST=15, it is assumed that approximately 15 dependent regions or threads are always active. During peak periods, if additional dependent regions or threads are started, IMS dynamically allocates a PST for each dependent region or thread, up to the MAXPST value. As PST are terminated, the PST are released until a value of 15 PST is reached. This support is within the constraints of the operating system or subsystem being used.