Feature

Germain UX RUM JS captures JavaScript tasks that occupy the UI main thread for 3 seconds or more. Usually that blocking and uninterrupted task causes:

  • delayed time to interactive (TTI)

  • high input and event handling latecy

  • bad animations and scrolling

By default, this monitoring is enabled for each User Monitoring Profile.

KPIs

KPIs for User Monitoring and Replay | JavaScript-Long-Task-Monitoring-KPIs

Example

Long Tasks on Drill-through

JS Long Tasks on Drill-through

Long Tasks on Session Replay

JS Long Tasks on Session Replay

Configuration

Threshold

You can update long task threshold by setting settings.plugins.performance.longtaskThresholdMillis in the Init Script.

The following code sample shows how to collect long tasks only if equal or longer than five seconds.

const settings = germainApm.getDefaultSettings();
...
settings.plugins.performance.longtaskThresholdMillis = 5000; // in milliseconds
...
germainApm.start(settings);
JS

Component: RUM JS

Feature Availability: 2022.2 or later

Browser Support: only latest Chrome, Edge and Opera