Fix SQL update logic (patch from 3.6.2)

layers/poi/update_poi_polygon.sql

@@ -0,0 +1,62 @@
+DROP TRIGGER IF EXISTS trigger_flag ON osm_poi_polygon;
+DROP TRIGGER IF EXISTS trigger_refresh ON poi_polygon.updates;
+
+-- etldoc:  osm_poi_polygon ->  osm_poi_polygon
+
+CREATE OR REPLACE FUNCTION update_poi_polygon() RETURNS VOID AS $$
+BEGIN
+  UPDATE osm_poi_polygon
+  SET geometry =
+           CASE WHEN ST_NPoints(ST_ConvexHull(geometry))=ST_NPoints(geometry)
+           THEN ST_Centroid(geometry)
+           ELSE ST_PointOnSurface(geometry)
+    END
+  WHERE ST_GeometryType(geometry) <> 'ST_Point';
+
+  UPDATE osm_poi_polygon
+  SET subclass = 'subway'
+  WHERE station = 'subway' and subclass='station';
+
+  UPDATE osm_poi_polygon
+  SET tags = slice_language_tags(tags) || get_basic_names(tags, geometry)
+  WHERE COALESCE(tags->'name:latin', tags->'name:nonlatin', tags->'name_int') IS NULL;
+
+  ANALYZE osm_poi_polygon;
+END;
+$$ LANGUAGE plpgsql;
+
+SELECT update_poi_polygon();
+
+-- Handle updates
+
+CREATE SCHEMA IF NOT EXISTS poi_polygon;
+
+CREATE TABLE IF NOT EXISTS poi_polygon.updates(id serial primary key, t text, unique (t));
+CREATE OR REPLACE FUNCTION poi_polygon.flag() RETURNS trigger AS $$
+BEGIN
+    INSERT INTO poi_polygon.updates(t) VALUES ('y')  ON CONFLICT(t) DO NOTHING;
+    RETURN null;
+END;
+$$ language plpgsql;
+
+CREATE OR REPLACE FUNCTION poi_polygon.refresh() RETURNS trigger AS
+  $BODY$
+  BEGIN
+    RAISE LOG 'Refresh poi_polygon';
+    PERFORM update_poi_polygon();
+    DELETE FROM poi_polygon.updates;
+    RETURN null;
+  END;
+  $BODY$
+language plpgsql;
+
+CREATE TRIGGER trigger_flag
+    AFTER INSERT OR UPDATE OR DELETE ON osm_poi_polygon
+    FOR EACH STATEMENT
+    EXECUTE PROCEDURE poi_polygon.flag();
+
+CREATE CONSTRAINT TRIGGER trigger_refresh
+    AFTER INSERT ON poi_polygon.updates
+    INITIALLY DEFERRED
+    FOR EACH ROW
+    EXECUTE PROCEDURE poi_polygon.refresh();