Queue adhoc tasks by duration

[djarran]

Description:
Reengagement modules are added to the queue by their ID in ascending order. It can take hours to process hundreds an entire queue.

$reengagementssql = "SELECT cm.id as id, cm.id as cmid, cm.availability, r.id as rid, r.course as courseid,
                            r.duration, r.emaildelay
                      FROM {reengagement} r
                INNER JOIN {course_modules} cm on cm.instance = r.id
                      JOIN {modules} m on m.id = cm.module
                     WHERE m.name = 'reengagement' AND cm.deletioninprogress = 0
                  ORDER BY r.id ASC";

It may be better to queue them based on their duration so that if we require an email to be sent 5 minutes after reengagement completion, this is performed earlier than one with a duration of 1 month.