I will highlight why the need is there to create a Custom Manager. Because Logically Custom managers will also take the resource from the same server from where other managers are running.

Can't we just increase the processes for the Standard manager and use the same. How will custom manager come into picture here.

Custom Managers are mostly created in various EBS instances/environments.
When an application user submits a request to run a program, the request is entered into a database table that lists all of the requests. Concurrent managers read requests from the table and start programs to run.

Custom Manager will be needed when:

  • Assign a predefined library of immediate concurrent programs to your manager.
    Immediate concurrent programs are subroutines associated with concurrent managers. All other concurrent programs are spawned as independent processes at run time.
  • Assign work shifts to your manager, which determines what days and times the manager works.
  • For each work shift, you define the maximum number of operating system processes the manager can run concurrently to read requests (start programs) during the work shift.
  • Specialize your manager to read only certain kinds of requests.
  • Long running Programs or Batch jobs are mostly included in Custom Managers.