How to run a long running job with ECS?

Questions & Answers
1

I have seen information talking about long running jobs in ECS, but have found no example. Just trying to not return the jobHandle from onUpdate does not work.

2

Here is an example:

using Unity.Collections;
using Unity.Entities;
using Unity.Jobs;

public class TestAsync2System : JobComponentSystem {
    int count = 0;
    JobHandle jobHandle;

    protected override JobHandle OnUpdate(JobHandle inputDependencies) {
        if (count == 0) {
            schedule(inputDependencies);
            UnityEngine.Debug.Log("inc count: "+count);
            count++;
        } else {
            if (jobHandle.IsCompleted) {
                UnityEngine.Debug.Log("completed: "+count);
                jobHandle.Complete();
                count = 0;
            }
        }
        return inputDependencies;
    }

    private void schedule(JobHandle inputDependencies) {
        NativeArray<bool> result = new NativeArray<bool>(1, Allocator.Persistent);
        result[0] = false;
        jobHandle = Job.WithDeallocateOnJobCompletion(result).WithCode(() => {
            for (long i = 0; i < 100000000; i++) {}
            result[0] = true;
        }).Schedule(inputDependencies);
    }
}

I’m not sure if that NativeArray should be necessary, but without it, it gives a burst error (but maybe that is a bug that will be resolved later).

More details here: https://forum.unity.com/threads/looking-for-example-how-to-do-a-long-running-job.812031/