Processes getting Queued - - Why only one of either Application Engine or SQR or Crystal report programs only get queued in PeopleSoft Process Scheduler?

In PeopleSoft Process Scheduler, ever wondered why only a particular process type gets queued? SQRs only get queued when all other Process Types keep running in Process Scheduler. Or Application Engines (AE) only gets queued while SQRs, Crystal Reports, COBOL programs keep running. This is because there could be already few instances of Application Engine running in the Process Scheduler of the same process type and the count of AE processes equals the threshold limit set in the System Settings of the Process Scheduler.

In such cases check the process scheduler/master process scheduler logs. It could reflect that few processes are running by utilizing the maximum system resources and not giving way for other process of the same process type due to the settings in PeopleTools -> Process Scheduler -> System Settings page.

In such cases, manually stop/kill the processes which are no longer required. Alternatively you can think about increasing the maximum number of process instances allowed for a particular process type in Process Scheduler -> System Settings.