The first checkpoint of an item and the final flush beside it both read no
state and both inserted; the loser failed on uq_plex_user_item. Two first saves
each made a Watch later list. Both are created by an ON CONFLICT DO NOTHING
insert and then read; a partial unique index holds one Watch later per user, and
the migration folds an existing second list into the first. Plex keeps one
per-item state map (rollup.item_state_map).
Channels, search and sync do no database work in their routes any more: reads go through
catalog/queries, writes through catalog/service, and a live search's ingest is catalog/search.
What a catalog route needs from Reader (a playlist's channels, a user's tag links, the feed
projection of results) it asks reader/queries and reader/service. The scheduler and the runs page
read channel titles and the work queue through catalog/queries. Catalog is fenced below its HTTP
layer: its owner filters go through userscope, it reads no other unit's tables, and its ingest
jobs commit only where they are named.
Feed, playlists, saved views, tags and the Home pins do no database work in their routes any more:
reads go through reader/queries (and feedquery for a feed page, its counts and facets), writes
through reader/service and discover/pins, which flush; the handlers commit. Reader is fenced below
its HTTP layer too: its owner filters go through userscope, and the catalog's jobs ask Reader
instead of joining its tables (the auto-tagger's system tags, the cleanup jobs' keep rule, the
maintenance notice). A playlist sync's catalog ingest moves to sync/videos.
peter