Accelerating Global CDN Cache Invalidation in Node.js with Custom C++ N-API Addons
You've pushed a critical content fix (wrong pricing, bad image, outdated copy) and the origin server is clean. Yet, 83 of your 100 edge nodes are still serving stale data to users. Your cache invalidation job ran and reported success, but the fixes aren't propagating correctly. This isn't a problem with your business logic. It's a failure in how your cache invalidation system calculates propagation order. When your edge nodes form a tiered, parent-child topology, purging the child node before the parent node leads to the child immediately re-fetching and re-caching the same stale content downstream. The root cause was an expensive, synchronous graph traversal in JavaScript to compute the correct invalidation order. Running Dijkstra's algorithm against a graph of 100 weighted nodes on the main thread was costing 40–60ms per purge cycle. Under concurrent load, the Node.js Event Loop choked, leading to job queuing, out-of-order execution, and ultimately, incorrect cache propagation. This
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