Scanner re-enqueues (priority 100) could silently promote pending legacy
backlog rows (priority -100) into the incremental lane via the enqueue
upsert's GREATEST, and the fail/release requeue branches hardcoded 100
regardless of the row's lane. A mass mtime shift or group-key-version
bump would have moved the entire legacy backlog out from under the
backfill task's pacing controls into the scheduled sync task.
Lane changes now happen only through terminal outcomes (complete or
discard); enqueue, fail, and release preserve a negative priority.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The ebook-metadata plugin attaches ~1s RetryInfo to ResourceExhausted
errors as request-pacing advice for its internal token bucket. Adopting
that hint verbatim as the queue horizon made rate-limited rows claimable
again immediately, so every backfill run re-claimed the same saturated
tail. Clamp rate-limited requeues to a 15m floor (SILO_EBOOK_RATE_LIMIT_COOLDOWN
to tune); hints above the floor are honored up to the existing 24h cap.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
