max_run_time = 0 means something different to Delayed::Worker than it does to Delayed::Backend::ActiveRecord:: Job.ready_to_run

[gorism]

Setting the Delayed::Worker.max_run_time to zero indicates that the Worker should not time out long running jobs. That is because it uses the Timeout library for managing timeout logic, and that is what zero means to that library.

However, the ready_to_run query doesn't special case that value, so it will end up selecting basically any job as "ready to run", because the conditional "OR locked_at < ?" (where ? = db_time_now - max_run_time) will almost always be true.