Job Scheduling and Batch Processing

The night shift

A bakery runs to a strict timetable overnight: mix the dough, let it rise, bake, cool, pack. Bake before it’s risen, or pack before it’s cooled, and the batch is ruined.

Most transaction processing, interfaces, backups and reports run as scheduled batch jobs, often overnight. If the wrong job runs, a job runs twice, or one fails without anyone noticing, data can end up wrong or missing in every downstream system.

Load transactions, calculate interest, post to ledger, reports and backup, each waiting for the previous job.

Job scheduling software runs the jobs automatically in the right order and at the right time. It enforces dependencies (a job waits until the one before it finishes successfully), reduces manual operator intervention, and logs everything that runs.

The controls

Controls over the schedule, over who can change it, and over failures.

Control	Detail
Authorised schedule	Only approved jobs are in the production schedule
Change management	New or changed jobs and schedules are approved and tested
Restricted access	Few people can add, change or delete jobs; operators can run but not edit
Dependencies	Jobs wait for the ones before them to complete successfully
Monitoring and alerts	Failures and unusual run times are flagged
Exception handling	Failures investigated; restarts from checkpoints
Rerun authorisation	Reruns approved and logged, with checks for duplicate processing
Ad hoc jobs	Jobs run outside the schedule need the same approval and logging
Logs	Job logs kept and reviewed
Output checks	Run-to-run totals and reconciliations confirm nothing went missing

A scheduled job can run with very powerful rights, so access to the scheduler is effectively privileged access. Review it like admin access.

Operators

Operators run the approved schedule and respond to failures. They shouldn’t be able to change job definitions, program code or input data, and their console activity should be logged.

Reruns

When a job fails halfway through, rerunning it from the start can process the first half twice.

Example. An interest accrual job fails halfway through. An operator reruns it from the start without authorisation. Half the accounts receive interest twice. A rerun procedure requiring approval, a restart from a checkpoint, and a run-to-run total check would have prevented it.

How the exam asks about it

If the question asks…	The answer is usually…
Main benefit of automated job scheduling	Reduces errors from manual intervention; enforces sequence
Control over changes to the production schedule	Change management with approval
Risk of unauthorised reruns	Duplicate processing
Who should be able to modify job definitions	A restricted, authorised group, not operators
Evidence that jobs ran as scheduled	Scheduler logs reviewed for exceptions

In short

Job scheduling software runs batch jobs automatically in the right order and at the right time, reducing operator error.
Only authorised, approved jobs should be in the production schedule; changes to schedules go through change management.
Access to the scheduler is restricted, because a scheduled job can run with powerful privileges.
Job outcomes are monitored; failures are investigated and reruns are authorised and logged.
Job logs and exception reports are reviewed to detect unauthorised or failed jobs.
Dependencies between jobs must be defined so later jobs don't process incomplete data.

Exam traps

Operators shouldn't be able to change job definitions or programs, only run approved schedules.
A rerun without authorisation can duplicate transactions.
Ad hoc jobs submitted outside the schedule need the same approval and logging.
Scheduler access is effectively privileged access; review it like admin access.

Slides

Click the slide and use the arrow keys. F toggles full screen.

If the question asks…	Answer
Main benefit of automated scheduling	Fewer manual errors; sequence enforced
Control over schedule changes	Change management with approval
Risk of unauthorised reruns	Duplicate processing
Who may modify job definitions	A restricted group, not operators
Evidence jobs ran as scheduled	Scheduler logs reviewed for exceptions