Gallery smart-search performance diagnostic — EXPLAIN ANALYZE on fork's OR-EXISTS vs upstream vs candidate UNION-CTE fix

gallery-search-diagnostic.sql

-- Gallery smart-search performance diagnostic
--
-- How to run:
--   1. Find your postgres container:  docker ps | grep postgres
--   2. Run (adjust container name, DB user, DB name as needed):
--        docker exec -i <your-postgres-container> psql -U postgres -d immich -XAt < this-file.sql
--      Or interactively:
--        docker exec -it <your-postgres-container> psql -U postgres -d immich
--      ...then paste the SQL below.
--
-- Only run on Gallery. Immich doesn't have shared_space tables, so queries 5 and 6 will fail there.
-- The Immich comparison value is just the request latency you've already measured.
--
-- Share the full output — especially the three EXPLAIN ANALYZE plans.

-- 1. Dataset shape
SELECT 'total_assets' AS label, COUNT(*)::text AS value FROM asset;
SELECT 'own_assets_top5' AS label, "ownerId"::text || ' -> ' || COUNT(*)::text AS value
  FROM asset GROUP BY "ownerId" ORDER BY 2 DESC LIMIT 5;
SELECT 'space_count' AS label, COUNT(*)::text AS value FROM shared_space;
SELECT 'space_asset_rows' AS label, COUNT(*)::text AS value FROM shared_space_asset;
SELECT 'space_library_rows' AS label, COUNT(*)::text AS value FROM shared_space_library;
SELECT 'smart_search_rows' AS label, COUNT(*)::text AS value FROM smart_search;

-- 2. vchord config + indexes
SHOW vchordrq.probes;
SELECT schemaname, tablename, indexname, indexdef FROM pg_indexes
  WHERE tablename IN ('smart_search', 'shared_space_asset', 'shared_space_library', 'asset')
  ORDER BY tablename, indexname;

-- 3. Planner stats (fresh)
ANALYZE asset;
ANALYZE shared_space_asset;
ANALYZE shared_space_library;
ANALYZE smart_search;

-- 4. Baseline EXPLAIN: ownerId-only (upstream-equivalent plan)
EXPLAIN (ANALYZE, BUFFERS)
SELECT asset.id FROM asset
INNER JOIN smart_search ON asset.id = smart_search."assetId"
WHERE asset."ownerId" = (SELECT id FROM "user" ORDER BY "createdAt" LIMIT 1)
ORDER BY smart_search.embedding <=> (SELECT embedding FROM smart_search LIMIT 1)
LIMIT 100;

-- 5. Fork EXPLAIN: OR-EXISTS (Gallery-equivalent plan)
EXPLAIN (ANALYZE, BUFFERS)
SELECT asset.id FROM asset
INNER JOIN smart_search ON asset.id = smart_search."assetId"
WHERE (
  asset."ownerId" = (SELECT id FROM "user" ORDER BY "createdAt" LIMIT 1)
  OR EXISTS (
    SELECT 1 FROM shared_space_asset ssa
    WHERE ssa."assetId" = asset.id
      AND ssa."spaceId" IN (SELECT id FROM shared_space LIMIT 100)
  )
  OR EXISTS (
    SELECT 1 FROM shared_space_library ssl
    WHERE ssl."libraryId" = asset."libraryId"
      AND ssl."spaceId" IN (SELECT id FROM shared_space LIMIT 100)
  )
)
ORDER BY smart_search.embedding <=> (SELECT embedding FROM smart_search LIMIT 1)
LIMIT 100;

-- 6. Candidate fix: IN-via-UNION-CTE
EXPLAIN (ANALYZE, BUFFERS)
WITH accessible AS (
  SELECT id FROM asset WHERE "ownerId" = (SELECT id FROM "user" ORDER BY "createdAt" LIMIT 1)
  UNION
  SELECT "assetId" FROM shared_space_asset WHERE "spaceId" IN (SELECT id FROM shared_space LIMIT 100)
  UNION
  SELECT a.id FROM asset a
    JOIN shared_space_library ssl ON a."libraryId" = ssl."libraryId"
    WHERE ssl."spaceId" IN (SELECT id FROM shared_space LIMIT 100)
)
SELECT asset.id FROM asset
INNER JOIN smart_search ON asset.id = smart_search."assetId"
WHERE asset.id IN (SELECT id FROM accessible)
ORDER BY smart_search.embedding <=> (SELECT embedding FROM smart_search LIMIT 1)
LIMIT 100;