Heroku, Puma, Redis, Sidekiq and Connection Limits , ERR max number of clients reached

Question

I am using heroku, puma ,redis to go with sidekiq. when I am trying to execute some background work that time is throwing Your Redis connection pool is too small for Sidekiq to work. Your pool has 20 connections but really needs to have at least 22

Please find below configuration files, Please help me find the solution

I am using

Redis To Go instance: Mini

procfile

web: bundle exec puma -C config/puma.rb  
worker: bundle exec sidekiq -C config/sidekiq.yml 

puma.rb

workers Integer(ENV['WEB_CONCURRENCY'] || 2)  
threads_count = Integer(ENV['MAX_THREADS'] || 1)  
threads threads_count, threads_count

preload_app!

rackup      DefaultRackup  
port        ENV['PORT']     || 3000  
environment ENV['RACK_ENV'] || 'development'

# Because we are using preload_app, an instance of our app is created by master process (calling our initializers) and then memory space
# is forked. So we should close DB connection in the master process to avoid connection leaks.
# https://github.com/puma/puma/issues/303
# http://stackoverflow.com/questions/17903689/puma-cluster-configuration-on-heroku
# http://www.rubydoc.info/gems/puma/2.14.0/Puma%2FDSL%3Abefore_fork
# Dont have to worry about Sidekiq's connection to Redis because connections are only created when needed. As long as we are not
# queuing workers when rails is booting, there will be no redis connections to disconnect, so it should be fine.
before_fork do  
  puts "Puma master process about to fork. Closing existing Active record connections."
  ActiveRecord::Base.connection.disconnect!
end

on_worker_boot do  
  # Worker specific setup for Rails 4.1+
  # See: https://devcenter.heroku.com/articles/deploying-rails-applications-with-the-puma-web-server#on-worker-boot
  ActiveRecord::Base.establish_connection
end 

In sidekiq.yml

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

sidekiq.rb

Sidekiq.configure_client do |config|
  config.redis = { url: ENV['REDISTOGO_URL'], size: 2 }
end

Sidekiq.configure_server do |config|
  config.redis = { url: ENV['REDISTOGO_URL'], size: 20 }

  Rails.application.config.after_initialize do
    Rails.logger.info("DB Connection Pool size for Sidekiq Server before disconnect is: #{ActiveRecord::Base.connection.pool.instance_variable_get('@size')}")
    ActiveRecord::Base.connection_pool.disconnect!

    ActiveSupport.on_load(:active_record) do
      config = Rails.application.config.database_configuration[Rails.env]
      config['reaping_frequency'] = ENV['DATABASE_REAP_FREQ'] || 10 # seconds
      # config['pool'] = ENV['WORKER_DB_POOL_SIZE'] || `
      config['pool'] = 16
      ActiveRecord::Base.establish_connection(config)

      Rails.logger.info("DB Connection Pool size for Sidekiq Server is now: #{ActiveRecord::Base.connection.pool.instance_variable_get('@size')}")
    end
  end
end

After deploying this configuration it throwing below error,

Your Redis connection pool is too small for Sidekiq to work. Your pool has 20 connections but really needs to have at least 22

later I have updated below details in sidkiq.rb,

Sidekiq.configure_client do |config|
  config.redis = { url: ENV['REDISTOGO_URL'], size: 2 }
end

Sidekiq.configure_server do |config|
  config.redis = { url: ENV['REDISTOGO_URL'], size: 22 }

  Rails.application.config.after_initialize do
    Rails.logger.info("DB Connection Pool size for Sidekiq Server before disconnect is: #{ActiveRecord::Base.connection.pool.instance_variable_get('@size')}")
    ActiveRecord::Base.connection_pool.disconnect!

    ActiveSupport.on_load(:active_record) do
      config = Rails.application.config.database_configuration[Rails.env]
      config['reaping_frequency'] = ENV['DATABASE_REAP_FREQ'] || 10 # seconds
      # config['pool'] = ENV['WORKER_DB_POOL_SIZE'] || `
      config['pool'] = 16
      ActiveRecord::Base.establish_connection(config)

      Rails.logger.info("DB Connection Pool size for Sidekiq Server is now: #{ActiveRecord::Base.connection.pool.instance_variable_get('@size')}")
    end
  end
end

This time it throwing another issue that

ERR max number of clients reached

I am getting this problem only in production, Please help me