Each AcoustID/integrity quarantine retry re-ran the FULL search (all queries,
all sources) before picking the next-best candidate — so a track that failed
verification a dozen times re-queried Soulseek a dozen times (~3 min/cycle in
the field). The next-best pick was already sitting in cached_candidates.
Now the monitor flags the re-queue as a quarantine retry; the worker walks the
already-found candidates first (skipping used + budget-exhausted sources) and
hands them straight to the download path — no search. A source is searched
exactly once: once its candidates are cached, later quarantine retries exclude
it (searched_sources) so the hybrid chain falls through to a not-yet-searched
source instead of re-querying the spent one. Fresh downloads and the monitor's
dead-connection/stuck retries clear searched_sources and search fresh, so the
only re-search is for a genuinely new source or a dead peer.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>