Batch processing presents three problems for system managers.
First, a batch process can impact other batch jobs running concurrently. Even if the batch jobs are scheduled to run during off-hours, for example, from 1 a.m. to 6 a.m., a system problem or a day of high transactions could cause the batch workload to spill over into business hours. Although not quite as bad as downtime, having a batch workload still running at 10:30 a.m. the next day could make online customers wait several minutes for each transaction, ultimately leading to fewer transactions.
Second, batch processes can never be run together with the online portion of the workload during business hours.
Third, problems with data, errors, and program crashes that occur during batch jobs bring the whole process to a halt. The inputs must then be carefully checked before the job can be run again. Even minor data errors, such as typos in dates, can prevent a batch job from running.