Planck's page reported a **0.175 s** block time against a true 29.8 — a factor
of 170 — flagged *measured* rather than nominal, so the headline block time, the
network hashrate (877 GH/s on a testnet nobody mines) and the window label were
all wrong and none of them looked it.
`measured_interval` divides elapsed time by height difference, which is the
chain's rate only if every height between two samples was watched arriving. A
gap fill is proof they were not. `record()` marked every head-stream block
`at_tip: true`, including the head that landed right after `fill_gap` closed a
1,251-block gap — so the pair straddling it measured how fast this observer
caught up. `ingest` now forgets its tip samples whenever it fills a gap and
records the closing head with `at_tip: false`. The interval goes nominal until
twenty fresh samples exist, which is `MIN_TIP_SAMPLES` doing its job: nominal
and labelled nominal beats measured and wrong.
The reported symptom was smaller and had the same root. `baba-gorchitsa` showed
three blocks in Planck's "six hours" having left for mainnet a day earlier — and
it was right to: 3,600 Planck blocks currently span **29 hours**, because the
chain's rate fell ninefold when its miners left. The label was built by
multiplying the block count by the current interval, which describes the rate
now rather than the period covered. It comes from `span_seconds` instead — the
authored-time span of exactly the blocks tallied, already the denominator of
every per-miner hashrate — and carries no "~", because nothing is estimated.
So the names went too. A window is a block count, and calling one `six_hours` is
a promise the site cannot keep on a chain whose rate moves; `/planck/six_hours`
was the reason a reader believed a day-old row was current. The selector reads
600 / 3.6k / 14.4k / 100.8k and the URL carries the count. Less friendly than
`6h`, and true on every chain. The old names still parse and are never emitted,
so shared links keep working — the router rewrites them.
Closes#14
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Jp6a8EDar9ueEhAxzep4V5
rob thijssen
ef367d5993
