Stackrig blogTech guides and explanations: servers, databases and the cloud. How things work and what they cost, with our own measurements and designs you can run.https://stackrig.dev/blog2026-10-02T00:00:00ZStackrighttps://stackrig.dev/Why does fan-out make fast services slow?https://stackrig.dev/fan-out-tail-latency2026-10-02T00:00:00Z2026-10-02T00:00:00ZA request that waits for 100 parallel calls is as slow as the slowest of them: the arithmetic of Dean and Barroso's paper, and the same effect in a design you can run.Why does p99 latency explode long before 100 % CPU?https://stackrig.dev/p99-latency-cpu-utilization2026-10-02T00:00:00Z2026-10-02T00:00:00ZThe queueing arithmetic for 1, 2 and 16 cores, what bursts do to it, our Postgres measurement, and the same curve in four designs you can open.How many users can a $12 server handle? We measured ithttps://stackrig.dev/how-many-users-12-dollar-server2026-09-30T00:00:00Z2026-09-30T00:00:00ZA $12-a-month VM with Nginx, Node.js and Postgres under virtual users: about 800 users at one second of think time, and a CPU throttle the guest does not show.How many requests per second can one Postgres handle?https://stackrig.dev/postgres-requests-per-second2026-09-30T00:00:00Z2026-09-30T00:00:00ZOne PostgreSQL on a 2-vCPU VM, measured: about 6,000 simple indexed reads per second at 100 % CPU, where p99 starts to climb, and how to estimate your own number.How big should your database connection pool be?https://stackrig.dev/database-connection-pool-size2026-09-30T00:00:00Z2026-09-30T00:00:00ZA pool of 4 against a pool of 16 connections on the same Postgres, measured, and Little's law for sizing your own.Cache hit ratio: what 80 % vs 95 % means for your databasehttps://stackrig.dev/cache-hit-ratio2026-09-30T00:00:00Z2026-09-30T00:00:00ZThe arithmetic of cache misses, and what a cold cache after a restart does to the database behind it.Retry storms: why retries take your service downhttps://stackrig.dev/retry-storms2026-09-30T00:00:00Z2026-10-02T00:00:00ZHow retries multiply load, why a storm can outlive its trigger, and the fixes that work, shown in a design you can run.System design interview: the URL shortener, simulated livehttps://stackrig.dev/system-design-url-shortener2026-09-30T00:00:00Z2026-10-02T00:00:00ZThe classic interview design with its numbers simulated over a real day of traffic: what breaks first, at which load, and what it costs.