Bug: previous logic advanced watermark to the latest session start_time including
ongoing sessions. PostHog session_recordings filters by start_time, so once a
session was 'seen' as ongoing the watermark moved past its start time and the
session was never re-fetched after it ended. Today 4 auth sessions on
/dashboard/vehicles/* and /dashboard/search (07:17-07:40 UTC) were lost this way.
Fix:
1. ROLLING_LOOKBACK_MINUTES (default 60): every cycle queries date_from =
min(watermark, now - 60min). Sessions that just finished get re-fetched
regardless of watermark drift. Upsert dedupes.
2. Track earliestOngoingStart; cap watermark to (earliestOngoingStart - 1s)
so subsequent cycles re-read that range.
Also added GET/DELETE /api/insights/watermark for manual reset (used to
trigger 24h backfill after this deploy).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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