The FE fired /feed/count (1 pass) + /facets (3 passes) on every filter change =
4 full scans of the subscribed set. New /api/feed/summary does ONE grouped query
(the base filter with tags stripped, GROUP BY channel_id -> per-channel video
counts) and derives the total count + every tag's distinct-channel facet count in
Python on the ~few-hundred-row channel map, faithfully mirroring filtered_query's
channel-based tag logic + the /facets drill-down (own category dropped, unless a
conjunctive topic-AND). Returns {count, facets} — the same numbers the two old
endpoints returned.
FE: a single shared query (Feed reads .count, Sidebar reads .facets); same key +
filters, so React Query dedupes to ONE request. Invalidations repointed to
qk.feedSummary. The old /feed/count + /facets endpoints (and their now-unused FE
api/qk) are kept as the equivalence-test oracle + safety net; a later cleanup can
drop them.
New equivalence test (test_feed_views, 8 filter combos incl. cross-category,
disjunctive/conjunctive topic modes, search): /feed/summary count == /feed/count
and facets == /facets, byte-identical. Structural win: 2 requests / 4-6 queries
-> 1 request / 2-3 queries (the review measured 530 -> 144 ms). Gate green:
344 pytest, frontend tsc/eslint/knip/prettier/222 vitest.
PERF-12: the search ORed `unaccent(channels.title) ILIKE '%q%'` straight into
the per-video predicate, which forced a full scan + detoast of every
search_vector and a per-candidate channel fetch. Pre-resolve the matching
channel ids (a few-hundred-row scan) and match `Video.channel_id.in_(ids)`
instead, so the planner keeps the search_vector GIN as a BitmapOr branch
(alongside ix_videos_channel_pub_desc). Empty match -> false() collapses the OR.
PERF-16: show=watched|hidden|in_progress used an outer join + coalesce(status,
'new'), so the planner couldn't start from the user's small video_states set.
Those views only return rows that HAVE a state, so inner-join video_states and
filter the raw column (status is NOT NULL on a present row, so it's identical).
'unwatched'/'all' keep the outer join. Dropped the now-dead position_expr.
New regression tests (test_feed_views): search returns both text- and channel-
name matches; the four watch-state views return the exact expected sets.
Measured on the prod-sized localdev reseed (prod planner, 0067/0068 applied):
- search /feed/count q=magyar: 663,463 -> 19,206 buffers (1,406 -> 31 ms; OLD
seq-scan+detoast -> NEW BitmapOr GIN+channel index)
- search feed page: 2,908 -> 1,479 buffers (32.6 -> 1.4 ms)
- show=watched (user with 64 watched): 40,661 -> 264 buffers (~154x)
Gate green (336 pytest, incl. the 2 new equivalence tests).
peter