Remove duplicate indexes from migration

idx_runs_submission_id and idx_runs_ranking already existed on prod
(as idx_runs_submission_id_covering and idx_runs_leaderboard_valid).
Keep only the two genuinely new indexes.

Author: Mark Saroufim

src/migrations/20260225_01_aW5Bu-add-leaderboard-performance-indexes.py

@@ -7,12 +7,6 @@
 __depends__ = {"20260108_01_gzSm3-add-submission-status"}
 
 steps = [
-    # FK index on runs.submission_id
-    # Used in every ranking query (JOIN runs ON submission_id = s.id)
-    step(
-        "CREATE INDEX IF NOT EXISTS idx_runs_submission_id ON leaderboard.runs(submission_id)",
-        "DROP INDEX IF EXISTS leaderboard.idx_runs_submission_id",
-    ),
     # FK index on submission.leaderboard_id
     # Every query filters WHERE leaderboard_id = X
     step(
@@ -25,13 +19,4 @@
         "CREATE INDEX IF NOT EXISTS idx_submission_user_id ON leaderboard.submission(user_id)",
         "DROP INDEX IF EXISTS leaderboard.idx_submission_user_id",
     ),
-    # Partial composite index for ranking queries
-    # Covers WHERE NOT r.secret AND r.score IS NOT NULL AND r.passed
-    # Includes (submission_id, runner, score) for JOIN, PARTITION BY, ORDER BY
-    step(
-        "CREATE INDEX IF NOT EXISTS idx_runs_ranking"
-        " ON leaderboard.runs(submission_id, runner, score)"
-        " WHERE NOT secret AND score IS NOT NULL AND passed",
-        "DROP INDEX IF EXISTS leaderboard.idx_runs_ranking",
-    ),
 ]