Support for not_queues

lib/delayed/backend/active_record.rb

@@ -60,9 +60,10 @@ def self.find_available(worker_name, limit = 5, max_run_time = Worker.max_run_ti
           scope = scope.scoped(:conditions => ['priority >= ?', Worker.min_priority]) if Worker.min_priority
           scope = scope.scoped(:conditions => ['priority <= ?', Worker.max_priority]) if Worker.max_priority
           scope = scope.scoped(:conditions => ["queue IN (?)", Worker.queues]) if Worker.queues.any?
+          scope = scope.scoped(:conditions => ["queue NOT IN (?)", Worker.not_queues]) if Worker.not_queues.any?
 
           ::ActiveRecord::Base.silence do
-            scope.by_priority.all(:limit => limit)
+            scope.by_priority.all(:limit => limit).shuffle
           end
         end
 
@@ -72,7 +73,15 @@ def lock_exclusively!(max_run_time, worker)
           now = self.class.db_time_now
           affected_rows = if locked_by != worker
             # We don't own this job so we will update the locked_by name and the locked_at
-            self.class.update_all(["locked_at = ?, locked_by = ?", now, worker], ["id = ? and (locked_at is null or locked_at < ?) and (run_at <= ?)", id, (now - max_run_time.to_i), now])
+            begin
+              self.class.update_all(["locked_at = ?, locked_by = ?", now, worker], ["id = ? and (locked_at is null or locked_at < ?) and (run_at <= ?)", id, (now - max_run_time.to_i), now])
+            rescue Exception => e
+              if e.message =~ /Deadlock found when trying to get lock/
+                0
+              else
+                raise e
+              end
+            end
           else
             # We already own this job, this may happen if the job queue crashes.
             # Simply resume and update the locked_at