As it turns out, connecting to redis may introduce a bit of problem if you're not aware of the conection handling.
I haven't tried with every client out there but especially the redis ruby client has this problem.
So imagine this scenario:
Every iteration will open a new file handle and will keep it open (I have not been waiting forever but I have seen open files for more than 24 hours).
Try this on a ruby console and monitor the open files with:
watch -n1 "lsof -p <PID> | grep <REDIS_PORT>"
Of course it's easy to fix in the example above but imagine you are writing a threaded program that accesses redis (e.g. Sidekiq worker).
In that case you want to implement a connection pool.
So be careful when spawning redis connections.