Race condition of creating a new job in JobQueueDataset
Description
After introducing composite trigger, notifications from different topics can trigger the same schedule. However, since each topic is handled by a separate thread, a thread can try to create a new job for a schedule while other threads also are also trying to create a new job for that same schedule.
After introducing composite trigger, notifications from different topics can trigger the same schedule. However, since each topic is handled by a separate thread, a thread can try to create a new job for a schedule while other threads also are also trying to create a new job for that same schedule.