Performance Audit Walkthrough: Finding Hidden Cache Misses

Performance Audit Walkthrough: Finding Hidden Cache Misses

Hook: Hidden cache misses silently inflate origin cost and slow users. This walkthrough gives you a repeatable audit you can run in a day to find the low-hanging misses and map remediation to measurable wins.

Audit overview

The audit has four phases: data collection, pattern analysis, targeted experiments, and rollout. We'll cover the metrics to collect, the queries to run, and remediation strategies aligned to product impact.

1) Data collection

• Collect edge and origin logs for a 7-day window.
• Record request headers that affect caching (Vary, Authorization, Cookies).
• Annotate flows by product area (checkout, search, profile, static assets).

2) Pattern analysis

Run queries to surface:

1. Top endpoints by miss volume.
2. Requests with cache-control headers preventing caching.
3. User segments generating most misses (mobile, regions).

3) Targeted experiments

Design small experiments to fix issues uncovered in analysis. Examples:

• Strip unnecessary Vary headers for static assets.
• Implement stale-while-revalidate for non-sensitive endpoints.
• Introduce signed cookies for personalization instead of caching per-user pages.

4) Rollout & measure

Deploy changes to a small cohort, monitor origin request rate and conversion, and gradually expand. Tie changes to KPIs — page load time, TTFB, and cost per 1,000 requests.

Case context

If your audit touches document processing or OCR flows, consider the trade-offs in DocScan Cloud OCR Platform — Capabilities, Limits, and Verdict and the related Security and Privacy in Cloud Document Processing for guidance on caching intermediate artifacts without breaking compliance.

For product teams working on lead capture or contact forms, the patterns in Contact Forms, Chat Widgets and Lead Capture Tools That Actually Work show how widget assets and payloads are safe targets for edge cache optimization.

Quick wins that often show up

• Caching the results of rate-limited third-party lookups for a few seconds.
• Using signed URLs for personalization so the CDN can cache canonical responses.
• Compressing payloads and avoiding cache-busting query strings for images and fonts.

Sample queries & scripts

Include queries to count per-endpoint misses and top cache-busting headers. (In this article we provide templates and a small script bundle in our repo.)

Closing

Run this audit quarterly. Hidden cache misses are cumulative and repairing them regularly preserves both performance and margin.