New Relic APM and Browser correlation for pre-optimization bottleneck measurement

Measuring a bottleneck before optimization requires comparing server-side latency from New Relic APM with client-side timing from New Relic Browser across the integration boundary. The goal is to attribute delay to backend transactions versus rendering and network time in the browser for a given user flow.

Correlation depends on distributed tracing linking a Browser page view to the APM transactions it triggers. Visibility is constrained by sampling and data retention settings on both sides, where higher fidelity improves bottleneck detection but increases ingestion volume and cost. Behavior is version-sensitive and automatic instrumentation may not cover all frameworks or SPA routers without manual configuration.

What sampling and retention configuration preserves correlation visibility between Browser page views and APM transactions while managing ingestion cost? How does mismatched sampling between APM agent and Browser affect trace completeness at the integration boundary? What configuration decisions ensure consistent attribution of latency to server versus client?