If you see a problem with a transaction then Diagnostic Session can help you investigate deeper. When triggered a Diagnostic Session captures transaction snapshots with full call graphs over a defined period of time.

It can be for single business transactions or multiple.

Frequency and duration are configurable.

Diagnostic sessions can be triggered automatically or manually

* Automatic Diagnostic Sessions

A session is automatically started when a threshold is crossed

-Default setting is when 10% is hit by any of the following

1. Errors
2. Slow transactions
3. Very Slow Transactions
4. Stalled transactions

To configure the thresholds go to Configure->Slow Transaction Threshold->Diagnostic Session Settings

Here you can configure:

1. Threshold
2. Frequency
3. Duration

-A Diagnostic Session can also be triggered by a health rule violation.

-Create a policy that triggers an action to start a diagnostic session when response time is too slow

To trigger a diagnostic session as an action.

1. Under Alert & Response->Actions->Create Action
2. Select ''Start a Diagnostic Session to collect Snapshots''

*Manually Triggered Diagnostic Session

To start a manual diagnostic session

1. Application Dashboard->Transaction Snapshots Tab->Diagnostic Sessions
2. Click the ''+'' to start a Diagnostic Session
3. Select one or more business transactions
4. Set the duration and frequency
5. Click ''Start Diagnostic Session''

You can also start a Diagnostic Session manually from the Business Transaction page.
1. Highlight the business transaction of interest
2. Select More Actions->Start Diagnostic Session

All snapshots appear in the Application Dashboard->Transaction Snapshots tab->Diagnostic sessions tab.