openmaptiles/layers/place/update_city_point.sql

DROP TRIGGER IF EXISTS trigger_flag ON osm_city_point;
DROP TRIGGER IF EXISTS trigger_refresh ON place_city.updates;

CREATE EXTENSION IF NOT EXISTS unaccent;

CREATE OR REPLACE FUNCTION update_osm_city_point() RETURNS void AS
$$
BEGIN

    -- Clear  OSM key:rank ( https://github.com/openmaptiles/openmaptiles/issues/108 )
    -- etldoc: osm_city_point          -> osm_city_point
    UPDATE osm_city_point AS osm SET "rank" = NULL WHERE "rank" IS NOT NULL;

    -- etldoc: ne_10m_populated_places -> osm_city_point
    -- etldoc: osm_city_point          -> osm_city_point

    WITH important_city_point AS (
        SELECT osm.geometry, osm.osm_id, osm.name, osm.name_en, ne.scalerank, ne.labelrank
        FROM ne_10m_populated_places AS ne,
             osm_city_point AS osm
        WHERE (
                (osm.tags ? 'wikidata' AND osm.tags->'wikidata' = ne.wikidataid) OR
                ne.name ILIKE osm.name OR
                ne.name ILIKE osm.name_en OR
                ne.namealt ILIKE osm.name OR
                ne.namealt ILIKE osm.name_en OR
                ne.meganame ILIKE osm.name OR
                ne.meganame ILIKE osm.name_en OR
                ne.gn_ascii ILIKE osm.name OR
                ne.gn_ascii ILIKE osm.name_en OR
                ne.nameascii ILIKE osm.name OR
                ne.nameascii ILIKE osm.name_en OR
                ne.name = unaccent(osm.name)
            )
          AND osm.place IN ('city', 'town', 'village')
          AND ST_DWithin(ne.geometry, osm.geometry, 50000)
    )
    UPDATE osm_city_point AS osm
        -- Move scalerank to range 1 to 10 and merge scalerank 5 with 6 since not enough cities
        -- are in the scalerank 5 bucket
    SET "rank" = CASE WHEN scalerank <= 5 THEN scalerank + 1 ELSE scalerank END
    FROM important_city_point AS ne
    WHERE osm.osm_id = ne.osm_id;

    UPDATE osm_city_point
    SET tags = update_tags(tags, geometry)
    WHERE COALESCE(tags->'name:latin', tags->'name:nonlatin', tags->'name_int') IS NULL;

END;
$$ LANGUAGE plpgsql;

SELECT update_osm_city_point();

CREATE INDEX IF NOT EXISTS osm_city_point_rank_idx ON osm_city_point ("rank");

-- Handle updates

CREATE SCHEMA IF NOT EXISTS place_city;

CREATE TABLE IF NOT EXISTS place_city.updates
(
    id serial PRIMARY KEY,
    t  text,
    UNIQUE (t)
);
CREATE OR REPLACE FUNCTION place_city.flag() RETURNS trigger AS
$$
BEGIN
    INSERT INTO place_city.updates(t) VALUES ('y') ON CONFLICT(t) DO NOTHING;
    RETURN NULL;
END;
$$ LANGUAGE plpgsql;

CREATE OR REPLACE FUNCTION place_city.refresh() RETURNS trigger AS
$$
BEGIN
    RAISE LOG 'Refresh place_city rank';
    PERFORM update_osm_city_point();
    -- noinspection SqlWithoutWhere
    DELETE FROM place_city.updates;
    RETURN NULL;
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER trigger_flag
    AFTER INSERT OR UPDATE OR DELETE
    ON osm_city_point
    FOR EACH STATEMENT
EXECUTE PROCEDURE place_city.flag();

CREATE CONSTRAINT TRIGGER trigger_refresh
    AFTER INSERT
    ON place_city.updates
    INITIALLY DEFERRED
    FOR EACH ROW
EXECUTE PROCEDURE place_city.refresh();