Refactoring: Make Scheduler more robust against job deletion while processing.

app/models/scheduler.rb

@@ -257,13 +257,20 @@ class Scheduler < ApplicationModel
       else
         _start_job(job)
       end
+
+      if job.present?
         job.pid = ''
         job.save
+
         logger.info " ...stopped thread for '#{job.method}'"
-      ActiveRecord::Base.connection.close
 
         # release thread lock and remove thread handle
         @@jobs_started.delete(job.id)
+      else
+        logger.warn ' ...Job got deleted while running'
+      end
+
+      ActiveRecord::Base.connection.close
     end
   end