Restarting CICS

One function of the CICS® attachment facility is to keep data synchronized between the two systems.

About this task

If Db2 completes phase 1 but does not start phase 2 of the commit process, the units of recovery that are being committed are termed indoubt. An indoubt unit of recovery might occur if Db2 terminates abnormally after completing phase 1 of the commit process. CICS might commit or roll back work without Db2 knowing about it.

Db2 cannot resolve those indoubt units of recovery (that is, commit or roll back the changes made to Db2 resources) until the connection to CICS is restarted.

Procedure

To restart CICS:

You must auto-start CICS (START=AUTO in the DFHSIT table) to obtain all necessary information for indoubt thread resolution that is available from its log. Do not perform a cold start.

You specify the START option in the DFHSIT table.

If CICS has requests active in Db2 when a Db2 connection terminates, the corresponding CICS tasks might remain suspended even after CICS is reconnected to Db2. Purge those tasks from CICS by using a CICS-supplied transaction such as:

Begin general-use programming interface information.

CEMT SET TASK(nn) FORCE

End general-use programming interface information.

If any unit of work is indoubt when the failure occurs, the CICS attachment facility automatically attempts to resolve the unit of work when CICS is reconnected to Db2. Under some circumstances, however, CICS cannot resolve indoubt units of recovery. You have to manually recover these indoubt units of recovery.