FBSimCity: an explorable city that shows how Firebird works

FBSimCity is an interactive visualization of Firebird internals: an explorable isometric city where every building is a subsystem from the classic Conceptual Architecture for Firebird paper (Chan & Yashkir), and queries commute through the pipeline as glowing particles — REMOTE harbor -> Y-valve -> DSQL -> JRD, with the lock manager tower watching over it.

The simulation is Firebird-flavored throughout: MGA record versions stack floors on towers with every UPDATE, the Next/OAT/OIT counters run live on the Transaction Hall — flip on a long-running transaction and watch the OIT pin garbage collection — a sweep truck tours the tables, and the page cache flashes hits and misses above the careful-writes excavation (no WAL here).

Version 0.3.0 adds a live version-chain inspector with real transaction ids, an accessible text walk of the whole pipeline at https://mariuz.github.io/FBSimCity/lifecycle.html plus a guided tour, a step-by-step query trace, scenario presets and shareable deep links like https://mariuz.github.io/FBSimCity/?scenario=stuckoit&warp=50&panel=mvcc which drops you into a stuck-OIT city with the chain inspector open.

Try it: https://mariuz.github.io/FBSimCity/

Source (MIT, plain HTML/JS, no build step): https://github.com/mariuz/FBSimCity

It is a model for intuition, not an emulator — corrections from people who know the engine internals are very welcome.