Is it a bad idea to run multiple dispatchers?

[kyrofa]

I've been running Solid Queue for a while now, with good success, but I had a bad experience today that has me re-thinking my configuration. I have a single Solid Queue instance running with the following configuration:

dispatchers:
  - polling_interval: 1
    batch_size: 500
workers:
  - queues: "*"
    threads: 3
    polling_interval: 0.1

Today I had the node running that instance turn into a zombie. It took me a while to convince AWS to kill it and give me another one, all while my job queue built up and my alarms went off. I prevent this kind of thing from causing downtime with our Rails instances by running multiple, on different nodes. Can I do the same thing with Solid Queue? I know I can run multiple workers, my concern is more about the dispatchers: will multiple entities putting things into the solid_queue_ready_executions table be okay?

[rosa]

Hey @kyrofa, no problem at all with running multiple dispatchers 👍 I assume you're scheduling many jobs in the future?

[kyrofa]

Thanks @rosa! Glad to hear it. Generally not that far in the future, primarily just a lot of ActiveJob perform_laters.

[kyrofa]

Is there anything I need to be concerned with, here? How are concurrency controls impacted by this?

[rosa]

primarily just a lot of ActiveJob perform_laters.

🤔 These are then enqueued directly into solid_queue_ready_executions. The dispatchers take care of jobs scheduled in the future, via set(wait: ...) like some of the examples here. If you're not enqueuing many of those, then multiple dispatchers won't increase the load significantly; they'll probably be idle most of the time.

How are concurrency controls impacted by this?

They won't be impacted in any way.

[kyrofa]

Ah! I didn't realize that aspect of the design. Thank you @rosa, I'll go ahead and close this 😄 .