The HRDPS pipeline as written was unusable in production: each chain
step took ~5 hours (not 30-90s as the dev-bench claim) because every
`wgrib2 -lon` batch redundantly JPEG2000-decodes ~150 records. With 57
batches × 18 forecast hours, a single cycle would take days to drain.
The /weather Canadian view only needs the current hour, so the cheapest
fix is to stop seeding the rest of the chain entirely:
* Rust grid: HRDPS_STEP=0.5 (was 0.125) drops point count 16× to ~3.5k.
Coarser cells than HRRR, but /weather gets visible Canadian coverage
inside one chain step (~20 min) instead of never.
* GridTaskEnqueuer.seed_current_hour/2 inserts exactly one forecast row
whose valid_time is closest to `now`. fh is clamped to 1..18 so the
Rust F00Reserved branch never fires.
* HrdpsGridWorker switches to seed_current_hour and drops the
6-hour-cycle cron in favor of HH:35 hourly fires. Reseeds are
idempotent on the 4-column unique key.
Also fixes a pre-existing credo "nested too deep" in
ScalarFile.read_point by extracting lookup_in_chunk + hit_or_false
helpers — happened to be on the read path that surfaces this work, so
folding it into the same commit.
Graham McIntire
d5726a89d5