The legacy filter queries projected ItemValue before grouping tags and genres. EF Core translated that shape into duplicated correlated aggregates, causing multi-minute requests for libraries with many distinct values and blocking unrelated SQLite-backed API calls.
Join ItemValuesMap directly to ItemValues before grouping. This preserves type and item filtering, clean-value grouping, minimum-value selection and ordering while producing one aggregate query. Add an in-memory SQLite regression test for result semantics and both SQL shapes.
Ordering mapped both keys to the item's own stored UserData row. Folders do not
have one: a series, season or box set counts as played when no descendant is
left unplayed, which is what the isPlayed filter and the DTO both report. A
mixed library therefore sorted every series and box set into the unplayed group,
and a query could filter and sort by two different notions of "played".
Extract the filter's predicate into BuildIsPlayedFilter and route both sort keys
through it so the two cannot drift apart again.
Rename GetItemsWithAlternateVersions to GetItemIdsWithAlternateVersions
across the interfaces and implementations since it returns ids. Return
the hashset straight from the query instead of materializing an array
first. Rename the DtoService guard to mayHaveAlternateVersions and
invert it so the computed path is the explicit case. Assert the media
source count value in the batch skip test and add a test covering an
item that is in the returned set still resolving to the correct count.
Browsing a page of videos with the MediaSourceCount field ran one alternate
version query per item, each opening a fresh DbContext. On a large library that
turned a single page into hundreds of sequential round trips and made the Items
endpoint take tens of seconds while holding a request thread the whole time.
Detect which videos own alternate versions once per page with a single query,
mirroring the existing people batch. Videos absent from that set have a single
media source, so the per item lookups are skipped for the common case. Behavior
is unchanged: a video with no alternates already resolved to a count of one.
Adds a regression test asserting the count resolves from the batch and the per
item lookups are never called.