What percentage threshold triggers an alert for long garbage-collection time in Dynatrace?

The correct answer indicates that a threshold of 40% triggers an alert for long garbage-collection time in Dynatrace. This percentage is significant because it strikes a balance between too frequent alerts for minor issues and insufficient alerts for critical performance degradation.

When garbage collection time exceeds 40% of the application's total CPU time, it suggests that the application may be spending an excessive amount of time in garbage collection, which can lead to performance issues such as increased response times or application slowness.

Setting the threshold at 40% ensures that the relevant stakeholders are notified when the application's performance could be impacted, enabling them to investigate and resolve potential issues proactively. Monitoring garbage collection is crucial because inefficient memory management can severely affect user experience and application reliability. Therefore, the 40% threshold is a strategic choice within Dynatrace’s capability to enhance application performance monitoring.

Understanding these thresholds and their implications allows teams to implement timely interventions to maintain application performance and user satisfaction.