Light1YT
36bdda9290
Rename 100_backfill_kn_price_per_m2.sql → 120_backfill_kn_price_per_m2.sql to avoid collision with three existing 100_* files on main (max was 119). Cast median_ppm2 to ::numeric in Pass 3 so ROUND(double precision, int) resolves to ROUND(numeric, int) — the double precision overload does not exist in PostgreSQL.
76 lines
3.4 KiB
PL/PgSQL
76 lines
3.4 KiB
PL/PgSQL
-- 120_backfill_kn_price_per_m2.sql
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-- Context: Issue #573 — domrf_kn_flats.price_per_m2 is populated in only ~3.7%
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-- of rows (status='free'/'sold'/'booked'). The 756 977 NULL-status rows imported
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-- from historical DOM.RF snapshots carry total_area but no price_rub, so the
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-- scraper's price_rub/total_area derivation never fires for them.
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-- This leaves 5/8 EKB districts with 0% price_per_m2 coverage and NULL district
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-- medians, blocking the Limit_District_Median_Partial analytics limitation.
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--
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-- Strategy (three-pass, most-precise source first):
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-- Pass 1 — direct arithmetic: price_rub / total_area where both columns present
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-- and price_per_m2 is still NULL or zero. Covers any rows the scraper
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-- missed (idempotent sanity net).
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-- Pass 2 — sale_graph join: use domrf_kn_sale_graph.price_avg (type='apartments',
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-- latest snapshot) as a proxy for the object-level avg ₽/м². Applied
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-- only to rows where Pass 1 left price_per_m2 NULL and the object has
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-- a sale_graph row.
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-- Pass 3 — peer median: for objects without sale_graph, derive price_per_m2 from
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-- the PERCENTILE_CONT(0.5) of free/sold/booked flats in the same obj_id.
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--
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-- Idempotent: WHERE price_per_m2 IS NULL guard prevents re-overwriting correct values.
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-- Dependencies: domrf_kn_flats, domrf_kn_sale_graph (migration 50_schema_kn_extensions.sql).
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-- Apply order: after 99_nspd_entities_denorm.sql.
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-- Estimated runtime on prod: < 30 s (785 K rows, index on obj_id exists).
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BEGIN;
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-- ── Pass 1: direct price_rub / total_area ────────────────────────────────────
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UPDATE public.domrf_kn_flats
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SET price_per_m2 = ROUND(price_rub / total_area, 2)
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WHERE price_rub IS NOT NULL
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AND total_area IS NOT NULL
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AND total_area > 0
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AND (price_per_m2 IS NULL OR price_per_m2 = 0);
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-- ── Pass 2: sale_graph proxy (latest snapshot, type='apartments') ─────────────
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-- domrf_kn_sale_graph.price_avg is the average contract ₽/м² reported by DOM.RF
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-- for the object in a given month. We use the most recent snapshot's average
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-- across all apartment sub-rows as a reasonable object-level proxy.
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WITH sg_latest AS (
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SELECT obj_id,
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AVG(price_avg) AS avg_ppm2
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FROM public.domrf_kn_sale_graph
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WHERE type = 'apartments'
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AND price_avg > 50000
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AND snapshot_date = (
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SELECT MAX(snapshot_date)
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FROM public.domrf_kn_sale_graph
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WHERE type = 'apartments'
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)
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GROUP BY obj_id
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)
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UPDATE public.domrf_kn_flats f
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SET price_per_m2 = ROUND(sg.avg_ppm2, 2)
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FROM sg_latest sg
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WHERE f.obj_id = sg.obj_id
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AND f.price_per_m2 IS NULL;
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-- ── Pass 3: peer median from free/sold/booked flats in same obj ───────────────
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-- Fallback for objects absent from sale_graph: compute the object-level median
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-- from the priced (status IS NOT NULL) flats in the same building.
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WITH peer AS (
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SELECT obj_id,
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PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY price_per_m2) AS median_ppm2
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FROM public.domrf_kn_flats
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WHERE status IS NOT NULL
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AND price_per_m2 IS NOT NULL
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AND price_per_m2 > 0
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GROUP BY obj_id
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)
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UPDATE public.domrf_kn_flats f
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SET price_per_m2 = ROUND(p.median_ppm2::numeric, 2)
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FROM peer p
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WHERE f.obj_id = p.obj_id
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AND f.price_per_m2 IS NULL;
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COMMIT;
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