Changing DBCTL resources online

An online change for DBCTL is different from CICS® resource definition online (RDO). You first use the offline process for doing a generation (whether it is an ACBGEN, or a partial MODBLKS generation for the DATABASE and APPLCTN macros). Guidance information about doing these generations is in System definition in IMS product documentation and Database utilities in IMS product documentation. To bring the new libraries online, use the /MODIFY command. First use the /MODIFY command with the PREPARE keyword to indicate the type of system definitions that must be replaced. Depending on the parameters entered, the system initiates quiescing of the appropriate resources. Then use the /MODIFY command with the COMMIT keyword to bring all newly defined resources online, update the changed resources, and invalidate the deleted resources. If the /MODIFY command deletes a database, the database is closed and made unavailable to programs. You cannot use the /MODIFY command on DEDBs.

If a failure occurs before a COMMIT completes, the changes defined by the /MODIFY command with the PREPARE keyword are not recovered across an emergency restart and you must reenter them. When a commit is successful, changes persist across all DBCTL restarts.

You can use the /MODIFY command with the ABORT keyword to reset the status that was set by the /MODIFY command with the PREPARE keyword. You can also use the /MODIFY command with the ABORT keyword if you have previously used the /MODIFY command with the COMMIT keyword, but it was not successful and you decide not to continue with the change. See also Finding out current status of DBCTL activities for details of using the /DISPLAY command with the MODIFY keyword.