使用sidekiq的heroku redis连接问题

Question

I am using Sidekiq to process jobs. I am using Heroku basic plan which allows up to 40 connections. My understanding is that each thread can have up to 1 connection. Sidekiq has a default number of threads of 25. In my thinking I should never be getting more than 25 connections.

But I have been getting too many connections errors to redis. How would this be posible? Should I cut down the number of Sidekiq workers? Or is there something else I can do? I currently have my Procfile like this:

worker: bundle exec sidekiq

Would switching it to this fix it?

worker: bundle exec sidekiq -c 10

Is it possible Sidekiq is not closing connections properly? Also, when I get this "too many connections" error, it basically brings down the site - is there a way to let if fail gracefully which it seems like it should do.

Answer 1

The short answer was that heroku wasn't accurately showing the number of connections which was tripping up any debugging. And I was pretty amateurish in figuring it out since Redis has pretty much worked.

My timeout was set to zero (determined via > heroku redis:info ) which basically meant that connections are held open indefinitely (the dashboard didn't show this accurately saying I was using like 10 when really having like 35).

Connecting to redis via heroku redis:cli and then running >CLIENT LIST showed the problem where there were many connections / clients probably in like TIME_WAIT state.

changing the timeout fixed this:

heroku redis:timeout --seconds 60 

Honestly, calling it a connection pool is a big inaccurate.