gendesign/tradein-mvp/backend/data/sql/097_index_hygiene.sql

-- 097_index_hygiene.sql
-- #730 index hygiene: drop exact-duplicate + redundant indexes;
-- de-partial is_active indexes. 87-unused sweep deferred (needs live pg_stat snapshot).
--
-- Context (Issue #730):
--   Duplicate drops: 5 named indexes that are exact duplicates of a surviving twin
--   or covered by a UNIQUE constraint (all confirmed from migration history below).
--   De-partial: 5 indexes on listings using WHERE is_active = true; since is_active
--   is 100% true in production the partial predicate saves nothing — a full index
--   strictly covers the same rows with no plan regression.
--
-- Idempotency:
--   All DROP INDEX use IF EXISTS; all CREATE INDEX use IF NOT EXISTS.
--   Safe to re-run.
--
-- Source evidence (each pair confirmed from migration files):
--   houses_kadastr_idx2        (050:93) dup of houses_cadastral_number_idx (029:180)
--   houses_addr_fp_idx         (028:20) dup of houses_fingerprint_idx2     (050:90)
--   listings_scraped_idx       (002:59) dup of listings_scraped_desc_idx   (050:62)
--   listing_sources_price_divergence_idx (042:8) dup of _idx2              (050:84)
--   houses_source_ext_idx      (009:59) redundant — covered by UNIQUE(source,ext_house_id) (009:54)
--
-- Dependencies:
--   002_core_tables.sql, 009_houses.sql, 028_matching_tables.sql,
--   029_extend_matching_valuation_dynamics.sql, 042_listing_sources_price_divergence_idx.sql,
--   050_search_optimization.sql

BEGIN;

-- =============================================================================
-- Step 1: Drop exact-duplicate and redundant indexes
-- =============================================================================

-- dup of houses_cadastral_number_idx (029_extend_matching_valuation_dynamics.sql:180)
-- same: ON houses (cadastral_number) WHERE cadastral_number IS NOT NULL
DROP INDEX IF EXISTS houses_kadastr_idx2;

-- dup of houses_fingerprint_idx2 (050_search_optimization.sql:90)
-- same: ON houses (address_fingerprint) WHERE address_fingerprint IS NOT NULL
DROP INDEX IF EXISTS houses_addr_fp_idx;

-- dup of listings_scraped_desc_idx (050_search_optimization.sql:62)
-- same: ON listings (scraped_at DESC) WHERE is_active = true
-- Note: listings_scraped_desc_idx is also de-partialed in Step 2 below.
DROP INDEX IF EXISTS listings_scraped_idx;

-- dup of listing_sources_price_divergence_idx2 (050_search_optimization.sql:84)
-- same: ON listing_sources (listing_id, price_rub) WHERE price_rub IS NOT NULL
DROP INDEX IF EXISTS listing_sources_price_divergence_idx;

-- redundant: covered by UNIQUE (source, ext_house_id) constraint (009_houses.sql:54)
-- which automatically creates a unique index on the same column set.
-- The plain btree here (009_houses.sql:59) is a strict duplicate of that unique index.
DROP INDEX IF EXISTS houses_source_ext_idx;

-- =============================================================================
-- Step 2: De-partial is_active=true indexes
-- Since is_active is 100% true, the WHERE predicate saves nothing.
-- A full index strictly covers the partial — no plan regression.
-- =============================================================================

-- listings_geom_active_idx (050_search_optimization.sql:47)
-- Original: ON listings USING GIST (geom) WHERE is_active = true
DROP INDEX IF EXISTS listings_geom_active_idx;
CREATE INDEX IF NOT EXISTS listings_geom_active_idx
    ON listings USING GIST (geom);

-- listings_active_filter_idx (050_search_optimization.sql:52)
-- Original: ON listings (rooms, price_rub, area_m2, scraped_at DESC) WHERE is_active = true
DROP INDEX IF EXISTS listings_active_filter_idx;
CREATE INDEX IF NOT EXISTS listings_active_filter_idx
    ON listings (rooms, price_rub, area_m2, scraped_at DESC);

-- listings_house_price_idx (050_search_optimization.sql:57)
-- Original: ON listings (house_id_fk, price_rub) WHERE is_active = true
DROP INDEX IF EXISTS listings_house_price_idx;
CREATE INDEX IF NOT EXISTS listings_house_price_idx
    ON listings (house_id_fk, price_rub);

-- listings_scraped_desc_idx (050_search_optimization.sql:62)
-- Original: ON listings (scraped_at DESC) WHERE is_active = true
-- Note: listings_scraped_idx (exact duplicate) already dropped in Step 1 above.
DROP INDEX IF EXISTS listings_scraped_desc_idx;
CREATE INDEX IF NOT EXISTS listings_scraped_desc_idx
    ON listings (scraped_at DESC);

-- listings_rooms_area_idx (002_core_tables.sql:58)
-- Original: ON listings (rooms, area_m2) WHERE is_active = true
DROP INDEX IF EXISTS listings_rooms_area_idx;
CREATE INDEX IF NOT EXISTS listings_rooms_area_idx
    ON listings (rooms, area_m2);

COMMIT;