Cyclic poller (BCyclicPoller)

This poller executes framework proxy points and alerts at even intervals across the time span as defined by the Min Interval, Max Interval and Rate.

Analytics pollers are different from Niagara interval triggers. Analytic pollers combine all the things you want the poller to do and attempts to accomplish your polling tasks (Size) within the Rate as defined on this Property Sheet. A poller attempts to schedule each component's execution during the period to spread out the work in an effort to minimize CPU impact, whereas a trigger executes all linked components at the same time and the station processes queued items as quickly as possible.

Figure 70. Example of a cyclic poller view

To view a cyclic poller Property Sheet, open the Poller Manager (double-click Config > Services > AnalyticService > Pollers), right-click a poller of type Cyclic Poller, and click Views > Property Sheet.

In addition to the standard property (Enabled), this component provides these properties.

Property	Value	Description
Size	read-only number	Indicates the number of alerts and Analyitc Proxy Ext components, which the poller is managing.
Progress	read-only percentage	Indicates the progress through the current cycle.
Last Cycle	read-only time	Displays the amount of time taken to run the last instance of the cycle.
Avg Cycle	read-only time	Displays the average amount of time required to run an instance of the cycle.
Max cycle	read-only time	Displays the maximum amount of time taken to run an instance of the cycle.
Min Interval	hours minutes seconds	Defines the minimum wait time between processing items in the queue. The default value of zero (0) does not enforce a minimum wait time. Triggered Poller components do not use a `Rate` property. You should use the `Min Interval` property to balance CPU load by slowing down the execution of items in the queue. For example, a queue size of 87344 with a `Min Interval` of 2 seconds creates a cycle that lasts a little over 48 hours.
Max Interval	hours minutes seconds	Defines the maximum wait time between processing items in the queue. The default value of zero (0) does not enforce a maximum wait time.
Rate	number	Establishes polling frequency by defining the amount of time between cyclic polls.

Poller examples

A cyclic poller tries to balance the execution by dividing the Rate by the number of items in the queue. The following table explains three poller examples.

Items in the queue	Rate	Min Interval	Max Interval	Execution
6	30	0	0	The poller attempts to execute an item once every five seconds, such that it executes all six items once every 30 seconds.
30	30	2	0	The poller needs to execute an item once every 1 second, but `Min Interval` = 2 seconds causing the poller to wait for 2 seconds between each item. The result: the poller executes all 30 items once every 1 minute, which is longer than the configured rate.
2	30	0	5	The poller needs to execute an item once every 15 seconds, but `Max Interval` = 5 seconds so the poller waits only 5 seconds between each item. The result: the poller executes the 2 items once every 30 seconds, but the items in the queue execute closer together, only 5 seconds apart instead of 30 seconds apart.