Automatic maintenance process
When a data set becomes full, the persistent data store selects an empty data set to make active. When the data set is active, the persistent data store checks to see if there are any more empty data sets. If there are no more empty data sets, maintenance is started on the oldest data set.
- &STC_HILEV.PD1
&STC_HILEV.PD1 is a procedure that is started by the automatic maintenance processing if one of the three maintenance functions is configured. Limited information is passed to this started task to drive a CLIST in a TSO environment. The configuration software creates this file and puts it into the RKANSAMU library for each runtime environment that has a persistent data store component. This procedure must be copied to a system level procedure library so the command issued to start it can be found.
The parameters passed to &STC_HILEV.PD1 vary based on the version of the configuration software and the persistent data store. This document assumes the latest version is installed. Three parameters are passed to the started task:
- HILEV
High-level qualifier for the runtime environment that configured this version of the persistent data store. It is obtained by extracting information from the DD statement that points to the persistent data store control files.
- LOWLEV
Low-level qualifier for the sample library. It currently contains the RKANSAMU field name.
- data set
Fully qualified name of the data set being maintained. It is possible to have a data set name that does not match the high-level qualifier specified in the first parameter.
- HILEV
- &STC_HILEV.PDC&STC_HILEV.PDC is the CLIST that is executed by the &STC_HILEV.PD1 procedure. The CLIST has the task of obtaining all of the information required to perform the maintenance, saving the data, and initialize the data set so it can be used again. This procedure performs the following actions:
- Checks the flags for BACKUP, EXTRACT, and EXPORT. If any of the flags is set, the CLIST performs the appropriate actions.
- Deletes the data set
- Allocates a new data set based upon the parameters in KppAL in RKANPARU
- Makes the new data set available for reading and writing
Before launching the &STC_HILEV.PD1 process, the persistent data store checks to see if BACKUP, EXPORT, or EXTRACT function has been specified. If no function has been specified, then the data set is initialized in the persistent data store started task and &STC_HILEV.PD1 is not executed.
PARMGEN configuration
uses the high-level qualifier for started tasks and appends PD1 for
the procedure and PDC for the CLIST. If you changed KPDPROC
to
some other than the default during configuration, the suffixes remain 1
and C
.
The procedure runs with the ID assigned to the procedure or your system
default ID.