When I increase sidekiq concurrency, it says my pool is too small. But smaller number works

Question

I'm a bit new to sidekiq but I managed to get it working pretty fine recently. However, I noticed that I needed to increase my concurrency from 5 to maybe 20-25. When I edited my sidekiq.yml file, which shows this:

development:  
  :concurrency: 5
production:  
  :concurrency: 20
:queues:
  - default

from 5 to 25, it threw me an error stating:

Your Redis connection pool is too small for Sidekiq to work. Your pool has 20 connections but really needs to have at least 27

What exactly is this error referring to? I even changed the "production" from 20 to 30, and it still claimed that my pool has 20 connections.

If I'm increasing the concurrency, why is it smaller all of a sudden? Any clarification would be greatly appreciated.

Answer 1

Remove any Redis :size parameter you have in your Sidekiq initializer. Sidekiq will auto-size your pools if you let it.