33cc41bacd
Review caught a boot-crash risk: 0038's repoint-UPDATE could set two non-canonical variant links of one manga to the same canonical id in a single statement (NOT EXISTS sees the pre-statement snapshot) -> manga_genres PK violation -> migration rollback -> startup failure. Replace with INSERT ... SELECT DISTINCT ... ON CONFLICT DO NOTHING (collision-proof) then delete variants. Amended in place (0038 is unpushed). Tested with the exact collision scenario. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
45 lines
2.3 KiB
SQL
45 lines
2.3 KiB
SQL
-- Enforce case-insensitive genre uniqueness, matching `authors` and `tags`
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-- (both got `UNIQUE (lower(name))` in 0009). `genres` only had a case-SENSITIVE
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-- `name UNIQUE`, but the crawler's `sync_genres` treats genres as
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-- case-insensitive (`WHERE lower(name) = lower($1)`) and can INSERT a new row
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-- from a source string. Under a race (or across ticks) two different-cased
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-- strings — "Isekai" vs "isekai" — could both miss the pre-check and both
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-- insert, since the exact-name unique doesn't collide. That leaves duplicate
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-- genre rows for one logical genre.
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-- Heal any pre-existing case-variant duplicates before adding the index, so
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-- `sqlx::migrate!` can't crash on a dirty table (mirrors 0031's pre-dedup).
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-- Canonical = lowest id per lower(name).
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-- 1. Ensure every manga linked to any case-variant also has the canonical link.
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-- INSERT ... ON CONFLICT DO NOTHING is collision-proof: SELECT DISTINCT
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-- collapses multiple variants of one manga to a single canonical row, and the
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-- ON CONFLICT absorbs a canonical link that already exists. (A prior
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-- UPDATE-repoint could set two non-canonical rows of the SAME manga to the
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-- same canonical id in a single statement and violate the manga_genres PK,
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-- rolling the migration back and wedging startup.)
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INSERT INTO manga_genres (manga_id, genre_id)
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SELECT DISTINCT mg.manga_id, k.keep_id
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FROM manga_genres mg
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JOIN genres g ON mg.genre_id = g.id
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JOIN (SELECT lower(name) AS lname, (array_agg(id ORDER BY id))[1] AS keep_id
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FROM genres GROUP BY lower(name)) k
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ON lower(g.name) = k.lname
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WHERE g.id <> k.keep_id
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ON CONFLICT (manga_id, genre_id) DO NOTHING;
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-- 2. Every non-canonical link now has a canonical sibling — drop the variants.
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DELETE FROM manga_genres mg
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USING genres g,
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(SELECT lower(name) AS lname, (array_agg(id ORDER BY id))[1] AS keep_id
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FROM genres GROUP BY lower(name)) k
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WHERE mg.genre_id = g.id AND lower(g.name) = k.lname AND g.id <> k.keep_id;
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-- Remove the now-orphaned duplicate genre rows.
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DELETE FROM genres g
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USING (SELECT lower(name) AS lname, (array_agg(id ORDER BY id))[1] AS keep_id
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FROM genres GROUP BY lower(name)) k
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WHERE lower(g.name) = k.lname AND g.id <> k.keep_id;
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CREATE UNIQUE INDEX genres_name_lower_uniq ON genres (lower(name));
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