place island topoint function

layers/place/island_polygon_update.sql

@@ -1,5 +1,43 @@
 -- etldoc:  osm_island_polygon ->  osm_island_polygon
-UPDATE osm_island_polygon  SET geometry=topoint(geometry)
+CREATE FUNCTION convert_island_polygon_point() RETURNS VOID AS $$
-WHERE ST_GeometryType(geometry) <> 'ST_Point';
+BEGIN
+  UPDATE osm_island_polygon  SET geometry=topoint(geometry) WHERE ST_GeometryType(geometry) <> 'ST_Point';
+  ANALYZE osm_island_polygon;
+END;
+$$ LANGUAGE plpgsql;
 
-ANALYZE osm_island_polygon;
+SELECT convert_island_polygon_point();
+
+-- Handle updates
+
+CREATE SCHEMA place_island;
+
+CREATE TABLE IF NOT EXISTS place_island.updates(id serial primary key, t text, unique (t));
+CREATE OR REPLACE FUNCTION place_island.flag() RETURNS trigger AS $$
+BEGIN
+    INSERT INTO place_island.updates(t) VALUES ('y')  ON CONFLICT(t) DO NOTHING;
+    RETURN null;
+END;    
+$$ language plpgsql;
+
+CREATE OR REPLACE FUNCTION place_island.refresh() RETURNS trigger AS
+  $BODY$
+  BEGIN
+    RAISE LOG 'Refresh place_island';
+    SELECT convert_island_polygon_point();
+    DELETE FROM place_island.updates;
+    RETURN null;
+  END;
+  $BODY$
+language plpgsql;
+
+CREATE TRIGGER trigger_flag
+    AFTER INSERT OR UPDATE OR DELETE ON osm_island_polygon
+    FOR EACH STATEMENT
+    EXECUTE PROCEDURE place_island.flag();
+
+CREATE CONSTRAINT TRIGGER trigger_refresh
+    AFTER INSERT ON place_island.updates
+    INITIALLY DEFERRED
+    FOR EACH ROW
+    EXECUTE PROCEDURE place_island.refresh();