Flow: order of jobs

[milenkovic]

If I add 2 flows to queue, with concurrency set to 1, I would expect for each flow to complete before next one, however I am getting slightly different behaviour.

await flowProducer.add({
  name: 'renovate-interior1',
  queueName: 'renovate',
  children: [
    { name: 'paint1', data: { place: 'ceiling' }, queueName: 'renovate' },
    { name: 'paint1', data: { place: 'walls' }, queueName: 'renovate' },
    { name: 'fix1', data: { place: 'floor' }, queueName: 'renovate' },
  ],
});
await flowProducer.add({
  name: 'renovate-interior2',
  queueName: 'renovate',
  children: [
    { name: 'paint2', data: { place: 'ceiling' }, queueName: 'renovate' },
    { name: 'paint2', data: { place: 'walls' }, queueName: 'renovate' },
    { name: 'fix2', data: { place: 'floor' }, queueName: 'renovate' },
  ],
});

Order of execution is next:

• paint1
• paint1
• fix1
• paint2
• renovate-interior1
• paint2
• fix2
• renovate-interior2

I would expect it to be(after all child jobs are finished, next one is parent job)

• paint1
• paint1
• fix1
• renovate-interior1
• paint2
• paint2
• fix2
• renovate-interior2

[manast]

First thing to consider with this case is that there are 2 different queues, so they will process jobs independently of each other. But even in the case where you used one single queue for both parent and children, BullMQ can only guarantee that children will be processed before the parent, not that all the children of all parents will be processed before all the parents.