RST—recoverable service table

Note on terminology: DBCTL refers to the CICS®—IMS/ESA® DBCTL (database control) interface.

The recoverable service table (RST) is used for CICS DBCTL XRF (extended recovery facility) support. It contains a description of the DBCTL configuration. On detection of a DBCTL failure, the active CICS system uses the RST together with the MVS™ subsystem VERIFY to determine the existence of a suitable alternative DBCTL subsystem. The alternate CICS system uses the RST to check for the presence of a DBCTL subsystem. For security reasons, the RST should be link-edited into a library authorized using APF. The RST is not loaded as part of the CICS nucleus.

You can code the following macros in a recoverable service table:
  • DFHRST TYPE=INITIAL establishes the control section.
  • DFHRST TYPE=RSE specifies the start of a recoverable service element (RSE). An RSE consists of a (nonempty) set of identifiers of equivalent DBCTL subsystems, the CICS applids associated with these DBCTL subsystems, and the application identifiers of the CICS systems which use the DBCTL subsystems.
  • DFHRST TYPE=SUBSYS specifies one of the DBCTL subsystems in an RSE.
  • DFHRST TYPE=FINAL concludes the RST (see TYPE=FINAL (end of table)).
The RST to be used by the system must be defined in the system initialization table by the following system initialization parameter:
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                       .-NO-.   
>>-DFHSIT--...--,RST=--+----+----------------------------------><
                       '-xx-'