delayed_job_active_record retry fix monkey patch see: https://github.com/collectiveidea/delayed_job_active_record/pull/91

delete_retry_fix.rb

require 'delayed/backend/active_record'

module Delayed
  module Backend
    module ActiveRecord
      class Job < ::ActiveRecord::Base
        def destroy
          retries = 0
          begin
            super
          rescue ::ActiveRecord::StatementInvalid => e
            if e.message =~ /Deadlock found when trying to get lock/ && retries < 100
              retries +=1
              retry
            else
              raise
            end
          end
        end
      end
    end
  end
end