Manually start change selector - Connect_CDC - aws_mainframe_modernization_service - connect_cdc_mimix_share - Latest

Normally, the kernel checks the status of the Change Selector and starts it if necessary on receiving the command to enable change capture, disable change capture or start a request. However, there are some instances where you may need to start the Change Selector manually.

For example, if a Change Selector is killed forcefully instead of being stopped gracefully in Connect CDC MonCon (see Stop the change selector), its status may be incorrect in Connect CDC MonCon. Examples of when a Change Selector is killed forcefully would be when the machine is shut down, or when a process shuts down or is killed by an unhandled exception (fatal exception in Windows or core dump on UNIX). In this case, the Change Selector may not start up automatically as a result of starting a request of enabling/disabling capture for a request.

To manually start a Change Selector:

1. In the Process view, highlight the change selector, then do one of the following:

   • Right-click and select Start

   • Select Change Selector>Start from the menu. For more information refer to Start change selector manually.

   The Start Change Selector dialog appears.

   If you choose to start all Change Selectors or if you are using UDB, you see a dialog similar to the following:

   

   If you are using IBM i, you see a dialog similar to the following:

   

2. Select either Warm Start or Cold Start for the Change Selector behaviors when starting or restarting. Note the following:

   • The first time a Change Selector is started, it must be cold started. Use a monitoring and control tool, such as Connect CDC MonCon, for a cold start.

   • Generally, you use Warm Start for all subsequent starts. To restart in cold start mode when the Change Selector is running, stop the Change Selector.

   The following table describes what occurs during a Change Selector cold start and warm start.

   OperatingSystem	Activity
   Cold Start
   IBM i	Begins reading from the currently attached receiver. In DB2/400, you can specify a starting receiver and a journal sequence number.
   UDB	Starts from the first transaction after the last committed transaction.
   Warm Start
   IBM i	Resumes reading from a specific journal sequence number (IBM i) within a journal request until no log records are available. Receiver lib/Name and Sequence Number are not active (greyed out.)
   UDB	Resumes reading from the first transaction after the last committed transaction. Receiver lib/Name and Sequence Number are not active (greyed out.)

3. If you selected Cold Start, do the following:

   1. Right-click the Change Selector, then select the Status tab to check the status of the Change Selector.

   2. If you are using IBM i, note the Receiver Library Name and the Receiver name. You enter these in the Start AS400 Change Selector dialog box.

   3. Right-click the Change Selector Name and select Start. The Start Change Selector dialog box displays.

   4. Select Cold Start.

   5. If you are using IBM i:

   • Enter the Receiver Library Name/Receiver Name in the Receiver lib/Name box.

   • Enter either a starting Sequence number or select First in receiver or Last in receiver from the Sequence number drop-down list.

4. If you selected Warm Start, set the defaults in the Connect CDC Director Process Definition Properties.

When the kernel starts the Change Selector automatically, it always uses the warm start option. If a Change Selector has never been started before, the Change Selector itself switches to a cold start without requiring user intervention.