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HealthLog/prisma/migrations
Marc-André Bombeck f5d259db58 feat(rollups): store per-bucket regression accumulators
Windowed slope, r2 and population sd still ran a live REGR_*/STDDEV_POP
query over the raw measurements partition on every warm-rollup request,
because the per-bucket mean cannot reconstruct an OLS regression over the
raw points in a window. The per-bucket sd/slope/r2 columns are a
within-bucket fold and do not compose linearly across DAY buckets.

Add the four regression-accumulator sums Postgres folds for REGR_* /
STDDEV_POP - sum_x, sum_xy, sum_xx, sum_yy - per (user, type,
granularity, bucketStart, source) over the same canonical-source rows
the live query reads, with the x-axis in epoch days. With n = count and
sum_y = mean*count already stored, all six terms are additive across
buckets, so a 7/30/90-day slope/r2/sd composes from the summed
accumulators with a bit-identical result to the live closed form.

Migration 0190 adds the four nullable columns; nullable keeps it
additive so existing rows read NULL until the boot re-fold refills them
(mirrors the v1.4.39 sum_value rollout). The populator emits the four
SUM terms inside the existing aggregate (no extra round-trip) and
persistRollupRows writes them. composeRegression / composeWindowedRegression
evaluate the closed form from already-collapsed buckets and return a full
miss when any in-window bucket lacks accumulators, so the reader falls
back to live SQL rather than composing a partial window.
2026-06-22 07:01:42 +02:00
..
2026-03-10 20:14:33 +01:00