Recently, we shipped an optimization to our global routing service that reduced its memory usage by 15%, improved time-to-first-byte (TTFB) from the 75th percentile and above by 10%, and significantly improved routing speeds for websites with many static paths.
A small number of websites, with hundreds of thousands of static paths, were creating a bottleneck that slowed down our entire routing service. By replacing a slow JSON parsing operation with a Bloom filter, we brought path lookup latency down to nearly zero and improved performance for everyone.