ChronicleQuantumLimit Element (ADF)
Specifies how far the logical (quantum) clock can fall behind the real-time clock before skipping event chronicle rule firings.
Syntax
<ApplicationExecutionSettings>
...
<ChronicleQuantumLimit>
Element Characteristics
| Characteristic | Description |
|---|---|
Data type |
Non-negative integer. |
Default value |
1,440 quanta, which is 1,440 minutes or 1 day, assuming a default QuantumDuration value of 1 minute. |
Special values |
0 indicates no chronicle quantum limit. No chronicle rule firings will be skipped. |
Occurrence |
Optional once per ApplicationExecutionSettings element. |
Updates |
Can be added, deleted, and modified when updating the application. |
Element Relationships
| Relationship | Elements |
|---|---|
Parent element |
|
Child elements |
None. |
Remarks
Notification Services uses a quantum clock to schedule rule firings. If the Notification Services engine that runs the application was down, or if the workload is causing the application to fall behind, the quantum clock can fall behind the real-time clock. This means that Notification Services falls behind on maintaining the chronicle (and any other actions performed by your chronicle rules).
Quantum limits ensure that the application does not fall too far behind the real-time clock, helping to ensure that newer data is processed in a timely manner.
To determine the value for this element, determine your application's maximum lag time between the quantum clock and the real-time clock and then divide that time by the quantum duration. For example, if you want a maximum lag time of 2 hours, and your quantum duration is 5 minutes, divide 120 by 5 and then set this element to the result (24).
If you set this value to 0 (zero), there is no chronicle quantum limit. Monitor your application using a report such as NSSnapshotApplications (Transact-SQL) to ensure that data is being processed in a timely manner.
If you do not specify a value for the ChronicleQuantumLimit element, remove the element from the ADF. The system default is used in this case.
Example
The following example shows a ChronicleQuantumLimit element that sets the chronicle quantum limit to 25 quanta. If the logical clock that keeps track of quanta falls 25 quantum intervals behind the real-time clock, the application will skip event chronicle rule firings to catch up to the 25 quanta limit.
<ChronicleQuantumLimit>25</ChronicleQuantumLimit>
See Also
Reference
Application Definition File Reference
SubscriptionQuantumLimit Element (ADF)
Other Resources
Specifying Quantum Limits
Updating Instances and Applications