The dense intra-day retention fold minted its daily-mean stats: row with
an externalId-keyed upsert. On real data a row already occupies the
canonical local-noon instant — a sibling daily stats: row or a per-sample
HRV/PULSE reading that fell on noon — so the upsert lookup missed (the
existing row carries a different externalId) and the INSERT then violated
the (user_id, type, measured_at, source, sleep_stage) unique index with
P2002. The mocked unit tests could not surface it.
Resolve the canonical row by the measured_at composite the collision is on
(sleep_stage IS NULL for these continuous types, matched via the
NULLS NOT DISTINCT index) and adopt it in place — refresh the mean, stamp
the canonical stats: externalId, un-tombstone — or create it when absent.
Exclude the adopted row id from the per-sample soft-delete so a noon-instant
sample becomes the daily row instead of being tombstoned.
Add a testcontainer integration test that seeds the colliding shape (a
pre-existing canonical-instant row plus out-of-window per-sample rows) and
pins no-P2002, coexistence, the noon-sample case, idempotency, and the
retention bound. Update the unit coverage for the adopt-in-place path.
Marc-André Bombeck
f049eeb8b1