-- Dedup SyncChapterContent jobs in flight.
--
-- Without this, the daemon's bookmark/cron enqueue paths would have to do a
-- pre-check + insert race that's incorrect under concurrency. The partial
-- unique index lets both producers use plain `INSERT ... ON CONFLICT DO
-- NOTHING`: at most one (pending|running) job per chapter_id exists, and the
-- slot frees again as soon as the job transitions to done/failed/dead so a
-- re-enqueue is possible after the row is reaped or a force-refetch is wanted.
--
-- Scoped to sync_chapter_content payloads only so Discover / SyncManga /
-- SyncChapterList jobs (which don't carry a chapter_id) remain un-deduped.
CREATE UNIQUE INDEX crawler_jobs_chapter_content_dedup_idx
    ON crawler_jobs ((payload->>'chapter_id'))
 WHERE state IN ('pending', 'running')
   AND payload->>'kind' = 'sync_chapter_content';