Analyze end-to-end request latency

Q: Analyze end-to-end request latency

This question evaluates proficiency in end-to-end latency analysis, observability and instrumentation (client and server), distributed tracing, performance engineering, and SLI/SLO definition.

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Question

Analyze and Improve End-to-End Request Latency

Context

A user request flows: Browser → CDN → Load Balancer → API Gateway → Microservices → Caches/Databases → Third‑party services → Response to Browser. You need to analyze and reduce end‑to‑end latency without harming reliability or throughput.

Assume modern browsers (Navigation/Resource/Long Tasks APIs), HTTP/2+, and backend microservices where you can add distributed tracing and metrics.

Tasks

Instrument both client and server to capture:
- Client: TTFB, Total Blocking Time (TBT), network RTT, resource timing, and user-perceived completion.
- Server: queueing time, service processing time, database query latency, cache hit/miss rates, and external dependency latency.
Attribute latency to frontend vs. backend components across the whole path.
Investigate p50/p95/p99 outliers and identify bottlenecks.
Propose changes or experiments to reduce latency without regressing error rate or throughput.
Define SLIs/SLOs, dashboards, and alerts for ongoing monitoring.

Analyze end-to-end request latency

Analyze and Improve End-to-End Request Latency

Context

Tasks

Solution

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Analyze end-to-end request latency

Overview

Analyze and Improve End-to-End Request Latency

Context

Tasks

Solution

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