Understanding scheduled tasks
A convenient feature of the Questra IDM Application Suite is the scheduled
task. By scheduling tasks – whether to collect readings from a
connected device, to transfer files from a device to your computer, or
to download software updates to a device – you can have the system
perform many of your tasks for you automatically.
NOTE: Scheduled tasks are not supported for disconnected
devices in Version 5.3, but are planned for a future release.
There are two types of scheduled tasks that you can create in the system.
Each has its advantages and disadvantages.
Enterprise
tasks are scheduled tasks that are initiated by the Enterprise
Server. Enterprise tasks are centrally managed, and hence are easy to
manage. Because they are centrally managed, Enterprise tasks increase
task response latency (see the discussion on non-contactable devices in
Messages,
contactable devices, and non-contactable devices) and increase the
load on the Enterprise Server throughout the life of the scheduled tasks.
Device tasks
are scheduled tasks that are initiated by devices. Because device tasks
are distributed to the devices, latency is encountered only when a scheduled
task is communicated to the device, not each time the scheduled task runs.
The distributed nature of Device tasks increases the load on the Enterprise
Server only when the task is created or deleted. Device tasks can be monitored
by the Enterprise Server. If a device does not report according to its
schedule, an alarm condition is submitted.
NOTE: There are no hard and fast
rules for deciding which type of task to use. If you are creating a task
that will stay around a while, will go to devices that have a long poll
interval, or will go to a large number of devices, a Device task will
work nicely. If you are creating a task that you intend on manually deleting
after a few cycles, an Enterprise task would be a better choice.
Scheduled tasks allow for a very rich set of recurrence rules, much
like a robust calendaring program. You can define a scheduled task to
run just one time or on recurring basis.
|
Best Practice for
managing scheduled tasks
|
When creating a scheduled
task, be sure to specify its duration by defining an expiration date.
Very few scheduled tasks should run "forever." If you do not
specify a duration, the system will perform the scheduled task "forever"
as requested, resulting in either the potential build-up of data on the
Enterprise Server or, worse, a number of error messages and/or alarms
for devices that are no longer in service.
A similar build-up of data
can result from a task of type Enterprise task that runs very frequently
on a large population of devices. This can happen if the task is assigned
to a group without your realizing how large the group is.
Finally, consider that frequent
schedules can result in a large load on the network and thus degrade system
performance. |
Because your computer, the devices you service, and the Enterprise Server
might be located in different parts of the world, it is important to understand
the dates and times for scheduled tasks. The system uses Coordinated Universal
Time (UTC) to specify the dates and times for scheduled tasks. While this
allows scheduling to occur at predictable, unambiguous times across the
globe, you may see readings whose timestamps may be off due to daylight
savings.
To define the actual schedule, see Common
scheduling fields. Once you have defined a scheduled task, save it
by clicking Add (or other equivalent, depending on the input dialog).
In some cases, you may need to manually start a scheduled task by clicking
the start task button 
where the task is shown on the list of tasks. You can stop a task whenever
you need to by clicking the stop task button 
. (Where applicable, this online Help will
point out when a task needs to be manually started and stopped.)
After a scheduled task has run as many times as you've set it up to
run, it will automatically be deleted. Prior to that time, you can manually
delete a scheduled task, just as you would any other kind of data you're
permitted to delete. Simply select the task on the dialog where it is
listed and click Delete 
.
NOTE: If the scheduled task you want to manually delete is
of type Enterprise task, it will be removed immediately from the dialog
where it is listed. If the scheduled task is of type Device task, there
may be a delay in how soon the task is removed from the list. This is
especially true if the scheduled task applies to a group of devices. The
task will not disappear from the list until all the devices in the group
report back that their copy of the task has been deleted.