If 2:00AM is the best time to run a heavy-process task, you can make A Trigger task to call your job URL everynight.
Solution Using A Trigger
Using A Trigger, time is not a problem at all. forget everything about time and just write
and make it accessible
task function on your url
Simplest way is to login to your A Trigger panel and create a task using the GUI. Also it's possible using API.
ATrigger.doCreate("1day", "http://example.com/admin/processUsers", tags, -1, "2013-08-26T02:00:00Z");
day for infinite times!