A threshold can be set at the application or business transaction level. Out of the box AppDynamics learns the applications behavior and sets threshold values for various activities on its own. The transactions performance is evaluated against these thresholds to determine if a response time is normal, slow, very slow, or stalled. This can be seen in the Transaction Scorecard in the application dashboard. When slow transactions are detected detailed snapshots are gathered to help troubleshoot. By default, thresholds are dynamically calculated based on the performance over the last two hours of activity. By default, if a request in a given transaction takes more than three standard deviations AppDynamics considers it a slow transaction. In the same manor very slow is determined if the transaction is four standard deviation. These numbers are calculated automatically and are constantly updated as transaction times change.

How to configure thresholds to an agreed upon SLA or critical baseline.

You can adjust the slow and very slow thresholds to match business requirements.

Go to Configure->Slow Transaction Thresholds on the Application Dashboard. Here you can configure thresholds for the entire application or for individual transactions

To change a threshold for just a business transaction expand the business transaction list and select the transaction you wish to configure. Change the defaults from standard deviation to a certain amount of milliseconds according to the business requirements. This is the same for slow and very slow transactions and then save the configuration.

You can also set the threshold to be a certain percentage over the average of the last two hours or however long you wish the time range to be.