Replay behavior differs depending on whether program execution has begun or not.
The program is not yet executing
If the program is loaded but has not started executing, enable ReplayEngine in any of the following ways:
• Click the Record toolbar button (shown selected)
• Select the Debug > Enable ReplayEngine menu item
• Execute the CLI command dhistory -enable
CLI: dhistory -enable
• Select Process > Startup Parameters from the Process Window, select the Debug Options tab, and then the Enable reverse debugging with ReplayEngine option. Click Apply.
ReplayEngine begins recording when the process starts executing. If you restart the process, ReplayEngine begins recording from the beginning of process execution.
To stop recording, exit the program and explicitly disable ReplayEngine. You cannot turn replay off while a process is executing.
For a parallel job, replay is enabled for all processes in the entire job, including at start and restart, unless you explicitly disable it.
The program is executing but halted
If a process is executing and stopped, you can immediately enable replay with any of the first three methods described above, but replay is enabled only while the program executes that single time. At process exit and restart, ReplayEngine will no longer be enabled unless you explicitly reenable it.
For a parallel job, only that process in the Process window will have replay enabled; other processes in the job will not.
Enabling ReplayEngine during program execution also means that you cannot step backward beyond the point at which ReplayEngine was enabled.
The fourth method discussed above, Process > Startup Parameters, requires a restart before it takes effect, meaning that Replay Engine will not be enabled on the currently executing process until it is restarted. For a parallel job, all processes will have replay engine enabled at restart.
