For a given transaction instance, a call graph may be available for some tiers but not all. These guidelines describe the rules for when the app agent captures transaction snapshots for the originating and downstream tiers in a transaction. They also describe the type of call graphs a snapshot might include depending on the cause for the snapshot. The guidelines apply to business transaction correlation as well as cross-application flow.

• Any tier (originating or continuing) takes a snapshot when it recognizes that it is experiencing slow, very slow, or stalled response times or has errors.
• An originating tier takes a transaction snapshot:
  • When the agent starts a diagnostic session on the originating tier because it has detected a pattern of performance problems. You can also manually start a diagnostic session from theBusiness Transaction Dashboard. See Diagnostic Sessions.
  • When the agent identifies slow, very slow, or stalled response times, or errors on the originating tier. These snapshots may have partial call graph information because they start at the time when the transaction slowed or experienced an error.
  • Based on the periodic collection schedule. By default, the agent captures one snapshot every 10 minutes.
• The downstream tier captures snapshots when the tier immediately upstream to it tells it to take a snapshot. An upstream tier might direct its downstream tier to take a snapshot under these circumstances:
  • The upstream tier is taking a snapshot for a diagnostic session.
  • The upstream tier is taking a snapshot based on the periodic collection schedule.