Release v0.2.0 — walk into it · NikolayS/PGSimCity

[0.2.0] — 2026-07-26

You can walk into it now. Still a prototype, still contains mistakes, and this
release names the ones we know about.

First person. Press G and drop into the city at eye height — walk, run,
crouch, jump. Collision is derived automatically from the component registry's
bounding boxes, so every building is solid without per-district authoring.
The plaza is reachable on foot. It was an island: its edge sits 40 m from
solid ground across the 52 m excavation. Four ramped causeways now cross it at
1:14, landing in the corridors that are clear of deck furniture, with gates cut
in the previously continuous railing. Every route was verified by walking a
capsule through the real collision world in code — 17 of 17 passed, and the
parapet stops you 0.25 m short of the drop.
A descent into the excavation — seven flights, 301 treads, from the pit rim
to the $PGDATA floor. At the bottom, a sign reads "shared memory is 52 m
above you", and the plaza's pylons are overhead.
The continuity quarter: anchors for base backups, point-in-time recovery
and failover — an archive estate with a timeline switchyard, a recovery ground
on separate iron a haul road away, and an HA quarter with a consensus store and
three lease posts. Geometry follows.
A server boundary. Clients now sit outside a fence with the gatehouse as
pg_hba.conf. Previously the application tier was drawn as a district of the
database, which every canonical Postgres diagram is explicit about.
Apache 2.0 licence, a NOTICE with the PostgreSQL trademark disclaimer, an
original elephant mark, favicon set and social preview.

The city no longer reads as an aerial assault. Clients came down to ground
level, the replication link stopped arcing to y=46 and became a duct bank at
grade, the selection marker stopped being four breathing corner brackets — a
weapons reticle — and became a surveyor's setting-out drawing, and the blinking
aviation beacons are gone. Red now appears only where it means something
specific, above all the dirty page.
Left-drag pans, right-drag orbits. Map convention, not CAD convention. Both
old habits still work via middle-drag and Ctrl-left-drag.
Labels place themselves like a map. Five zoom levels with cross-fade,
screen-space collision, leader lines, wall-clock hysteresis, and a +N pill so
a district can never read as empty. The establishing shot went from 26 labels
with 9 overlapping pairs to 9 with none; the backend row from 29 overlapping
pairs to one.
autovacuum_vacuum_scale_factor ships at 0.02, not PostgreSQL's 0.2. At
stock the demo tables need ~5,900 dead row versions to cross the threshold —
roughly an hour at 10 tps — so the vacuum yard would be dead for a whole visit.
0.02 is what the documentation recommends per-table for a busy relation.
Default workload is 10 tps at 20% writes, so a single transaction can be
followed end to end.

66 verified PostgreSQL corrections, after four specialists reviewed every
word and a second panel cross-examined each contested finding. The worst class
is gone: catalog objects that did not exist — SLRU as a wait_event_type,
TransactionBuffer, an Analyze phase in pg_stat_progress_vacuum. Also: the
full-page-image surge begins when a checkpoint starts, recycled WAL segments
are not zeroed, WAL insertion takes the lock before reserving space, the xmin
horizon is per-database, and synchronous_commit = on is a local flush
guarantee.
Binary units. fmtBytes() divided by 1024 and labelled the result kB/MB/GB.
Now KiB/MiB/GiB everywhere, except inside quoted PostgreSQL config values.
Pause froze nothing. The frame loop scaled simulated time but handed real
time to the world and the particles, so pausing drained rather than stopping,
and timeScale desynchronised the two clocks.
A WebGL context leak in the support probe, teardown firing on bfcache restore,
the fps meter measuring the clamped delta it was designed to hide stalls with,
and districts lit only by neon collapsing to black silhouettes at low quality.
The quality selector did nothing at all.
The top-bar vitals danced on every update.

Cache hit ratio reads about 57%, which is not what an OLTP database looks
like. Two compounding defects: the gauge is a time-average of ratios rather
than blks_hit/(blks_hit+blks_read), and the working set is sized so the
shared_buffers slider never leaves the steep part of the curve.
Achieved throughput does not respond to bottlenecks. A batch controller
cancels them out, so lock contention, tiny shared_buffers and slow commits
all fail to reduce committed transactions. The causes are simulated correctly;
the effect is unreachable.
WAL-triggered checkpoints fire at the full max_wal_size rather than
max_wal_size / (1 + checkpoint_completion_target).
The shared-buffer grid saturates to white under heavy load and stops encoding
state — exactly when the city gets interesting.
Mobile layout: panels cover most of the viewport (#1).
The minimap paints over the guided-tour caption.
Walk mode inherits the flying camera's downward pitch on entry.