Analysis of CICS restart information

When CICS shuts down, you can programmatically determine the type of shutdown that occurred, and whether it is safe to override the next restart type and perform a cold restart of the CICS® system.

DFHRMUTL provides the SET_AUTO_START keywords to automatically restart a CICS system with a specific override. The keywords can include AUTOCOLD, which makes CICS perform a cold start. A CICS system that was shut down using a warm shutdown, and which had no indoubt, commit-failed, or backout-failed units of work (UOWs) keypoints at that time, can be restarted cold without loss of data integrity. However, if the system was not shut down in a controlled manner, or there are such units of work recorded on the system log, do not perform a cold restart, because system data integrity can be compromised.

To help you determine whether a cold start of the region system is appropriate or not, CICS provides the following information:
  • The following DFHRMUTL summary information:
    • The next CICS start type found on the global catalog, DFHGCD.
    • If the next CICS start type is warm, counts of the units of work that were in an indoubt, commit-failed, or backout-failed state when CICS was shut down.
  • A CICS global catalog record with the following VSAM KSDS key: 
    X'00000011C4C6C8D9D4C4D440C4C6C8D9D4C4D46DD9C5E2E3C1D9E340'
    This record contains three fullword counts following the key:
    • The number of indoubt UOWs
    • The number of commit-failed UOWs
    • The number of backout-failed UOWs
    If any of these counts contains a number greater than zero, recovery information for the units of work is present on the CICS system log. In this case, a modification of the CICS autostart override record to AUTOCOLD is not appropriate, because system data integrity would be jeopardized.

    CICS deletes this global catalog record during restart, and writes it during a controlled shutdown. Therefore presence or absence of the record on the catalog indicates whether the CICS system was previously shut down warmly; that is, by the use of CEMT PERFORM SHUTDOWN or the Shutdown option from the CICS Explorer® Regions operations view. If the record exists on the global catalog, and the three count fields are zero, it is safe to use DFHRMUTL to modify the autostart override record to specify AUTOCOLD.

    Here is an example of this record, showing the presence of one indoubt unit of work at the time CICS was shut down: 
    KEY OF RECORD - 
00000011C4C6C8D9D4C4D440C4C6C8D9D4C4D46DD9C5E2E3C1D9E340

00000011C4C6C8D9D4C4D440C4C6C8D9D4C4D46DD9C5E2E3C1D9E34000000001 
0000000000000000

    You can use the DFHRMRED Assembler DSECT in a batch program to map the global catalog record. DFHRMRED is found in the CICSTS52.CICS.SDFHMAC library.

For more information about the DFHRMUTL utility, see Recovery manager utility program (DFHRMUTL).