Fail Safe level‑1 processing guarantees consistency when updating both TDS and CA‑IDMS data from a single instance of TIBCO Service Gateway for IDMS/DB in a single transaction. At the end of a transaction, the Data Object Broker requests that the Gateway commit outstanding updates. As part of CA‑IDMS commit processing, the Gateway initiates another run unit for the transaction database, updates the database to record the successful commit, issues a FINISH for the transaction database run unit, and then issues a FINISH for the original run unit. If the Gateway does not respond to the Data Object Broker in a reasonable amount of time, the transaction is flagged as being in doubt. Locks held on TDS data remain in place until the problem is resolved.
When a connection is re-established between the Data Object Broker and an instance of TIBCO Service Gateway for IDMS/DB with the same configuration as the one that failed, the Data Object Broker asks the Gateway if the in-doubt transaction completed. The Gateway checks the CA‑IDMS transaction database to determine this. If CA‑IDMS has completed the update, the TDS updates are applied and the locks are released.
To implement Fail Safe level‑1 processing, you must define a CA‑IDMS transaction database. The DDL required to define the database is located in the CNTL data set, in members XIDMTRX1, XIDMTRX2, XIDMTRX3, and XIDMTRX4.
Do not change the CA‑IDMS record name; however, you can change the schema and subschema names. If the subschema name is changed, ensure you include the TRXDB parameter (specifying the new subschema name) when the Gateway is started. This transaction table holds a maximum of one record for each combination of TIBCO Service Gateway for IDMS/DB and Data Object Broker.
Use the CA‑IDMS extract program S6BIDUTL or S6BIDU12 to extract the CA‑IDMS element, record, set, and index information from the IDD that you defined in
Define a transaction database. For more information, refer to
Task A, Extracting CA‑IDMS data dictionary information.
After loading the CA‑IDMS subschema definition into TIBCO Object Service Broker, you must define a TIBCO Object Service Broker IDMS/DB transaction table to contain the CA‑IDMS data in these fields. By default this table is called @IDMFSTRXDB and its fields must match the fields in the CA‑IDMS transaction database.
The transaction table can be managed in TIBCO Object Service Broker like any other IDM table. For example, you can write a TIBCO Object Service Broker rule to clean up the Fail Safe database on shutting down the Gateway.