Hi. I am developing an application in PHP on Linux/Apache. I want to be able to schedule PHP jobs (scripts) for execution at some specific time in the future from within the application.

I know that many people will recommend cron and at, but first of all I don't need recurrence (cron) and secondly and most importantly, I need the solution to be able to scale. At was not designed with race condititions in mind, and if two users try to add a job at the same time one or both may fail.

It's also important that jobs are executed at their specified time, and not just 'polled' once per minute or so.

Can anyone please suggest solutions for this task? Thank you.