Cache Invalidation - Refresh vs Refetch
summary
Apache Traffic Control adds an invalidation type called refetch that forces caches to treat a resource as a miss and retrieve it from origin (not just revalidate), addressing misconfigured origins that return 304 despite changed content. Implementation modifies the jobs DB schema, exposes the field in the API (PR 6118), requires a global parameter refetch enabled, and uses t3c to generate config for the regex revalidate plugin in ATS. Tests updated, docs and UI tweaks remain; feature works but is flagged as intentionally inefficient.
AI-written summary · about
chapters (10)
- 0:00Introduction to caching
- 2:17Why use caching
- 6:31HTTP caching standards
- 9:00Manual revalidation with invalidation
- 11:04Refresh vs refetch explained
- 12:34Implementation plans
- 14:44Demo of new features
- 18:53Propagation to caches
- 20:51Caution on refetch usage
- 22:16Q&A on RFC submission
related talks
34mThe underappreciated power of content invalidation
26mCache Strategies with Best Practices
27mCaching for Cash
16mWhat's next in the HTTP caching world
23mCacheCatalyst: Enhancing Web Caching for the Latency-Constrained Internet
14mReactive state for the backend
26mWhat’s next in the HTTP caching world
44m#BackToBasics: The HTTP Cache