Advanced Settings - Throttling

Throttling is used to restrict a task from being executed. Usually throttling is used when a task is triggered by a frequently occurring event. Under certain circumstances, throttling may prevent a trigger from being fired. Each time the trigger is triggered, it is evaluated according to the schema below. Only those triggers which meet the specified conditions would then make the task execute. If no throttling conditions are set, all trigger events would run the task.

Throttling_2

There are two types of conditions for Throttling: time-based and statistical. For a task to be executed:

It has to pass both types of conditions

Conditions must be set; if a condition is empty, it is omitted

All time-based conditions must pass, as they are evaluated with the AND operator

All statistical conditions evaluated with the AND operator must pass; at least one statistical condition with the OR operator must pass

Statistical and time conditions set together must pass, as they are evaluated with the AND operator—only then is the task executed

 

If any of the defined conditions are met, stacked information for all observers is reset (the count starts over from 0). This holds for time-Based as well as statistical conditions. This information is also reset if the Agent or ERA Server is restarted. All modifications made to a trigger reset its status. We recommend that you only use one statistical condition and multiple time-based conditions. Multiple statistical conditions can cause unnecessary complications, and can alter trigger results.

Time-based criteria

All of the configured conditions must be fulfilled in order to trigger the task.

Aggregate invocations during time period (T2) - Allow triggering once during the specified time period. If for example, this is set to ten seconds and during this time ten invocations occur, only the first would trigger the event.

 

Time ranges (T1) - Allows triggering only within the defined time period. You can add multiple time ranges to the list—they will be sorted chronologically.

 

Statistical criteria

 

Statistical criteria application - Statistical conditions can be combined using either the AND logical operator (all conditions must be fulfilled) or the OR logical operator (the first condition fulfilled triggers the action).

 

Triggered every No of occurrences (S1)- Allows only every x-th trigger hit. For example, if you enter ten, only each tenth triggering will be counted.

 

No of occurrences within a time period (S2) - Allows only triggering within the defined time period. This will define the minimal frequency of events to trigger the task. For example, you can use this setting to allow the execution of the task if the event is detected 10x in an hour. Firing of the trigger causes a counter reset.

Time period - Define the time period for the option described above.

A third statistical condition is available only for certain trigger types. See: Trigger > Trigger type > Event Log Trigger.

 

Event log criteria

This criteria are evaluated by ERA as third statistical criteria (S3). The Statistical criteria application operator (AND / OR) is applied to evaluate all three statistical conditions together. It is recommended to use event log criteria in combination with the Generate Report task. All three fields are required for the criteria to work. The buffer of symbols is reset if the trigger is fired and there is a symbol already in buffer.

Symbol - According to Log type, which is set in the Trigger menu, you can choose a symbol in the log which you can then search for. Click Change to display the menu. You can remove the selected symbol by clicking Remove.

Number of events with symbol - Enter the integer number of distinct events with selected symbol to run the task.

Applies when number of events - This sets what type of events would trigger the condition. The available options are:

Received in a Row - Selected number of events must occur in a row. These events must be distinctive.

Received Since Last Trigger Execution - The condition is triggered when the selected number of distinctive events is reached (since last task execution).

 

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When in use with a Server Task, all client computers are considered. It is unlikely to receive higher number of distinctive symbols in a row. Use the Received in a Row setting only for reasonable cases. A missing value (N/A) is considered as "not unique" and therefore the buffer is reset in this point.

Additional properties

As stated above, not every event will cause a trigger to fire. Actions taken for non-firing events can be:

If there is more than one event skipped, group the last N events into one (store data of suppressed ticks) [N <= 100]

For N == 0, only the last event is processed (N means history length, where the last event is always processed)

All non-firing events are merged (merging the last tick with N historical ticks)

 

If the trigger fires too often or you want to be notified less often, consider the following suggestions:

If the user wants to react only if there are more events, not a single one, see statistical condition S1

If the trigger should fire only when a cluster of events occur, follow statistical condition S2

When events with unwanted values are supposed to be ignored, refer to statistical condition S3

When events from outside relevant hours (for example, working hours) should be ignored, see time-based condition T1

To set a minimum time between trigger firings, use time-based condition T2

 

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The conditions can also be combined to form more complex throttling scenarios. See the throttling examples for more details.