Little's law

The number of requests in a system equals arrival rate times time spent: 1,000 requests per second at 200 ms means 200 requests in flight. It sizes thread pools, connection pools and queues.

Where it shows up in real systems

  • Database connection proxy

    Place it between your services and a relational database. Serverless functions and large fleets open far more connections than a database can hold; the proxy multiplexes them and also shortens failovers by holding connections while the standby takes over.

    In production: PgBouncer, Amazon RDS Proxy, ProxySQL, Odyssey, Supavisor

See it break, then fix it

Build an architecture, send it a day of traffic and outages, and learn why it holds or fails. Free to start.

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