Do not run the job if it is already running

Question

I am making a simple Sprint batch application that reads from a CSV file and writes it into the database. I want to throw an exception when we try to trigger a job that is already running. So before starting the job, I am checking if there is already a job running using this code

JobInstance lastJobInstance = jobExplorer.getLastJobInstance(job.getName());

        if (lastJobInstance != null) {
            List<JobExecution> runningExecutions = jobExplorer.getJobExecutions(lastJobInstance);

            for (JobExecution execution : runningExecutions) {
                if (execution.getStatus() == BatchStatus.STARTED  || execution.getStatus() == BatchStatus.STARTING) {
                    throw new IllegalStateException("Job is already running: " + job.getName());
                }

            }

        }

But In my DB (batch_job_execution table )i see an entry :

job_execution_id	version	job_instance_id	create_time	start_time	end_time	status	exit_code	exit_message	last_updated	job_configuration_location
13	1	13	2023-08-16 13:36:59.410	2023-08-16 13:36:59.459		STARTED	UNKNOWN		2023-08-16 13:36:59.459

This means that there was some Job that started but never completed and the reason for it is not known. Its exit code shows UNKNOWN. This job was run weeks ago it didn't fail nor completed (The reason is not known) Also when a job has started and is currently going on its exit code also shows UNKNOWN.

I am not able to understand how to filter this job out and make sure to not run a job if it is already running.

So now whenever Im trying to run a new job it gives me "Job is already running" error because of this particular entry. Is there any way to filter out this entry because it is a very old entry and it might not get completed or failed ever

My DB batch_job_execution

Answer 1

I want to throw an exception when we try to trigger a job that is already running

I am not able to understand how to filter this job out and make sure to not run a job if it is already running.

This is done automatically by Spring Batch if you correctly define your job instances. In your example, if the input file is an identifying job parameters, running the same job instance will lead to a JobExecutionAlreadyRunningException. So there is no need to write the code you shared and manually check the existence of running executions.

Now if the job execution was abruptly terminated, then it is up to you to decide if you want to restart it or abandon it. In this case, you need to manually change its status in the database, see Aborting a Job.