bot-backend
a4057a5b28
Co-authored-by: bot-backend <bot-backend@gendsgn.local> Co-committed-by: bot-backend <bot-backend@gendsgn.local>
115 lines
5.2 KiB
PL/PgSQL
115 lines
5.2 KiB
PL/PgSQL
-- 99a_quarter_price_index.sql
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-- Issue #760 — Materialized view mv_quarter_price_index: per-cadastral-quarter
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-- price index normalized to EKB city median. Foundation for estimator #647-3.
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--
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-- Naming: deploy.yml applies files via `ls -1 data/sql/*.sql | sort` (lexicographic).
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-- '99a_' sorts AFTER '99_nspd_entities_denorm.sql' because '_' (0x5F) < 'a' (0x61).
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-- Files 100_–122_ sort before 99_ (since '1' < '9') — they are already applied.
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-- This file applies last of all current migrations.
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--
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-- Dependencies:
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-- - public.mv_quarter_price_per_m2 (created by 95_mv_quarter_price.sql)
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-- Columns used: quarter_cad_number (varchar), deals_count (bigint), median (float8)
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--
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-- Methodology:
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-- 1. Source: mv_quarter_price_per_m2, filter scope = all 66:% quarters present.
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-- 2. City normalizer (city_median): percentile_cont(0.5) over EKB (66:41:%) quarters
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-- with deals_count >= 5. Computed in SQL — NOT hardcoded.
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-- 3. District fallback: per district prefix substring(quarter_cad_number for 5)
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-- (e.g. '66:41'), district_median = median of quarter medians (deals_count>=5).
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-- 4. price_index assignment:
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-- deals_count >= 5 → q.median / city_median basis='quarter'
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-- deals_count < 5 + district exists → district_median / city_median basis='district'
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-- no data → 1.0 basis='city_fallback'
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-- 5. Coverage: all 66:% quarters (Sverdlovsk oblast), normalizer = EKB city median.
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--
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-- REFRESH CONCURRENTLY: enabled via UNIQUE index on quarter_cad_number.
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-- Re-apply: DROP MATERIALIZED VIEW IF EXISTS ... CASCADE makes it idempotent.
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-- _schema_migrations tracking prevents re-apply in prod (deploy.yml guard).
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--
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-- Validation snapshot (2026-05-30, source MV current):
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-- city_median ≈ 110,883 ₽/m²
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-- total 66:% quarters covered: 1,972
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-- basis breakdown: quarter=1,708 / district=262 / city_fallback=2
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-- NULL price_index: 0
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-- index range: 0.2771 – 3.9788
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-- Near-1.0 quarter: 66:41:0313118 (index=1.0000, q_median=110,883)
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-- Top quarter: 66:41:0401018 (index=3.9788, q_median=441,176 — центр ЕКБ)
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-- Low quarter: 66:17:0806002 (index=0.2771, q_median=30,722 — периферия области)
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-- City-fallback examples: 66:00:0000000 (null-district), 66:39:0302011 (district no data)
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BEGIN;
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DROP MATERIALIZED VIEW IF EXISTS mv_quarter_price_index CASCADE;
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CREATE MATERIALIZED VIEW mv_quarter_price_index AS
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WITH
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-- All 66:% quarters from source MV (Sverdlovsk oblast scope)
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all_66_quarters AS (
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SELECT
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quarter_cad_number,
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deals_count,
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median,
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substring(quarter_cad_number FOR 5) AS district_prefix
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FROM mv_quarter_price_per_m2
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WHERE quarter_cad_number LIKE '66:%'
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),
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-- City normalizer: equal-weight median-of-quarter-medians for EKB (66:41:%)
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-- Uses only quarters with deals_count >= 5 to suppress noise.
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city_median_cte AS (
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SELECT
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percentile_cont(0.5) WITHIN GROUP (ORDER BY median) AS city_median
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FROM all_66_quarters
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WHERE quarter_cad_number LIKE '66:41:%'
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AND deals_count >= 5
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),
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-- District fallback: median of quarter medians per district prefix,
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-- also restricted to deals_count >= 5 quarters.
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district_medians AS (
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SELECT
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district_prefix,
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percentile_cont(0.5) WITHIN GROUP (ORDER BY median) AS district_median
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FROM all_66_quarters
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WHERE deals_count >= 5
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GROUP BY district_prefix
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)
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SELECT
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q.quarter_cad_number,
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CASE
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WHEN q.deals_count >= 5 THEN q.median / c.city_median
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WHEN dm.district_median IS NOT NULL THEN dm.district_median / c.city_median
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ELSE 1.0
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END::double precision AS price_index,
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q.deals_count AS n_deals,
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CASE
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WHEN q.deals_count >= 5 THEN 'quarter'
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WHEN dm.district_median IS NOT NULL THEN 'district'
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ELSE 'city_fallback'
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END::text AS basis,
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NOW() AS computed_at
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FROM all_66_quarters q
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CROSS JOIN city_median_cte c
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LEFT JOIN district_medians dm ON dm.district_prefix = q.district_prefix
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WITH NO DATA;
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-- UNIQUE index required for REFRESH MATERIALIZED VIEW CONCURRENTLY.
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-- Also serves as O(1) PK lookup for the estimator (#647-3).
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CREATE UNIQUE INDEX IF NOT EXISTS mv_quarter_price_index_uq
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ON mv_quarter_price_index (quarter_cad_number);
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-- Initial populate (non-concurrent — MV is empty, CONCURRENTLY not allowed on empty MV).
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REFRESH MATERIALIZED VIEW mv_quarter_price_index;
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COMMENT ON MATERIALIZED VIEW mv_quarter_price_index IS
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'Per-cadastral-quarter price index normalized to EKB city median (=1.0). '
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'Source: mv_quarter_price_per_m2. Scope: all 66:% (Sverdlovsk oblast) quarters. '
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'city_median = percentile_cont(0.5) over 66:41:% quarters with deals_count>=5. '
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'basis: quarter (>=5 deals) | district (sparse, district fallback) | city_fallback. '
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'Refresh: CONCURRENTLY safe (UNIQUE index on quarter_cad_number). '
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'Consumer: estimator service (#647-3) reads O(1) by quarter_cad_number. '
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'Issue: #760.';
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COMMIT;
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