Ruby on Rails - Job Delay - Job Queue is not added to the database

The delayed_jobs table is not added to the job queue when it is daemonized. But it works when it is not demonized.

I have three rake tasks (a.rake, b.rake, c.rake).

In a.rake

task :run_a => :environment do
  A.new.get_a_data
end

class A
 def get_a_data
   ...
   schedule_next_a_job
 end

 def schedule_next_a_job
   get_a_data
 end

handle_asynchronously :get_a_data, :run_at => Proc.new { 2.minutes.from_now }, :queue => 'a'
end

      

        
        
        
      

    

In b.rake

task :run_b => :environment do
  B.new.get_b_data
end

class B
 def get_b_data
  ...
  schedule_next_b_job
 end

 def schedule_next_b_job
   get_b_data
 end

handle_asynchronously :get_b_data, :run_at => Proc.new { 5.minutes.from_now }, :queue => 'b'
end

      

        
        
        
      

    

In c.rake

namespace :run do
  task :start do
  `rake run_a`
  `rake run_b`
  if Rails.env == 'development'
    `QUEUES=a,b rake jobs:work`
  else
    `RAILS_ENV=production bin/delayed_job --queues=a,b start` 
  end

  task :stop do
  `rake jobs:clear`
  end
end

      

        
        
        
      

    

In the console, I run as shown below:

RAILS_ENV=production rake run:start # to start jobs worker
rake run:stop # to clear my jobs worker

      

        
        
        
      

    

In my table of slowed down jobs, last_error shows how:

Failed to load job: undefined class / module A

Load failed: undefined class / module B

Can anyone help me get rid of this problem?

Thanks in Advance.