It is currently not possible to schedule the execution of a method with parameters, see TaskScheduler.php#L98
This is required to be able to send PDF/HTML/SMS at different times, see #3706.
In a first iteration, only one parameter will be supported.
Tasks that are being scheduled are stored in the option table in the option name "TaskScheduler.timetable".
In future updates of Piwik, if a scheduled task is not needed anymore, it would not be removed from the option table.
See TaskScheduler.php#L80 :
/* * Task has to be executed if : * - it is the first time, ie. rescheduledTime is not set * - that task has already been executed and the current system time is greater than the * rescheduled time. */
The task should only be scheduled and not run.
Note: do not break the $forceScheduledTasks feature.