A type served from day buckets (pulse or glucose past 90 days, and since
the previous change a dense pulse stream on any window) is drawn one point
per day, each the day's mean at the day's start. The summary line counted
those points as measurements, and the FHIR export stamped the last day's
mean as the latest observation: a value and a time nobody measured.
The day-bucket stats now carry when their newest reading was taken
(`latestAt`). `latestReading` returns that reading when it is there, and
the summary line counts each type's readings from its stats. Raw series
are unchanged: their stats count equals their points and their last point
is the newest reading.
Past 90 days every pulse reader already folded in SQL. Inside it, three
still read every raw heart-rate row, which on a watch that records a
reading a minute is 130 000 rows per read (#1023):
- The insights page's resting-pulse proxy, used when an account has no
resting heart rate, walked the whole window to take one percentile per
day and held the event loop for over a second per view. It now folds in
Postgres (`readRestingPulseProxy`) with the same percentile, rounding,
minimum-sample rule and day anchor.
- The per-kind series sent every reading: 14.7 MB for 90 days. A pulse
window with more than 10 000 readings is now bucketed per local hour,
mean plus low/high band, with stats still over the readings.
- The doctor report drew every reading into one sparkline. A pulse window
over the same cap now takes the per-day path longer reports already use.
Sparse pulse (a cuff, hourly imports, a watch sampling every few minutes)
stays under the cap and keeps its raw shape.
Marc-André Bombeck