PGSimCity: an explorable 3D city that visualizes PostgreSQL internals

PGSimCity is an independent, non-commercial educational project that turns a running PostgreSQL cluster into a walkable, breakable 3D city. Districts map to real internals — backend processes, the shared_buffers pool, WAL, checkpointing, autovacuum and replication — with every building's behavior tied to actual Postgres formulas such as the WAL trigger point, cache hit ratio and the clock-sweep usage-count cap.

It targets engineers who are strong technically but have never operated a database, letting them see why checkpoints spike latency, how a forgotten open transaction bloats tables indefinitely, and what synchronous_commit actually costs. Built-in scenarios like cache thrash, long-running transactions, checkpoint storms and slow replica replay make these effects observable in real time rather than theoretical.

Rather than running actual PostgreSQL source, the project ships a scaled model validated against official documentation through multiple expert review rounds and backed by a 234-test suite. It runs entirely in the browser, built with three.js, TypeScript and Vite, with no install and no framework dependency.