GIST index must be applied before simplifying

schema/layers/boundary.sql

@@ -89,35 +89,34 @@ CREATE OR REPLACE VIEW boundary_z10 AS (
 CREATE OR REPLACE FUNCTION layer_boundary (bbox geometry, zoom_level int)
 RETURNS TABLE(geom geometry, admin_level int, scalerank int, class text) AS $$
     SELECT geom, admin_level, scalerank::int, class FROM (
-        SELECT * FROM boundary_z0 WHERE zoom_level = 0
+        SELECT * FROM boundary_z0 WHERE geom && bbox AND zoom_level = 0
         UNION ALL
-        SELECT * FROM boundary_z1 WHERE zoom_level BETWEEN 1 AND 2
+        SELECT * FROM boundary_z1 WHERE geom && bbox AND zoom_level BETWEEN 1 AND 2
         UNION ALL
-        SELECT * FROM boundary_z3 WHERE zoom_level = 3
+        SELECT * FROM boundary_z3 WHERE geom && bbox AND zoom_level = 3
         UNION ALL
-        SELECT * FROM boundary_z4 WHERE zoom_level = 4
+        SELECT * FROM boundary_z4 WHERE geom && bbox AND zoom_level = 4
         UNION ALL
-        SELECT * FROM boundary_z5 WHERE zoom_level BETWEEN 5 AND 6
+        SELECT * FROM boundary_z5 WHERE geom && bbox AND zoom_level BETWEEN 5 AND 6
         UNION ALL
-        SELECT * FROM boundary_z7 WHERE zoom_level = 7
+        SELECT * FROM boundary_z7 WHERE geom && bbox AND zoom_level = 7
         UNION ALL
         SELECT ST_Simplify(geom, 400) AS geom, admin_level, scalerank, class
-        FROM boundary_z8 WHERE zoom_level = 8
+        FROM boundary_z8 WHERE geom && bbox AND zoom_level = 8
         UNION ALL
         SELECT ST_Simplify(geom, 320) AS geom, admin_level, scalerank, class
-        FROM boundary_z8 WHERE zoom_level = 9
+        FROM boundary_z8 WHERE geom && bbox AND zoom_level = 9
         UNION ALL
         SELECT ST_Simplify(geom, 150) AS geom, admin_level, scalerank, class
-        FROM boundary_z10 WHERE zoom_level = 10
+        FROM boundary_z10 WHERE geom && bbox AND zoom_level = 10
         UNION ALL
         SELECT ST_Simplify(geom, 100) AS geom, admin_level, scalerank, class
-        FROM boundary_z10 WHERE zoom_level = 11
+        FROM boundary_z10 WHERE geom && bbox AND zoom_level = 11
         UNION ALL
         SELECT ST_Simplify(geom, 50) AS geom, admin_level, scalerank, class
-        FROM boundary_z10 WHERE zoom_level = 12
+        FROM boundary_z10 WHERE geom && bbox AND zoom_level = 12
         UNION ALL
         SELECT geom, admin_level, scalerank, class
-        FROM boundary_z10 WHERE zoom_level >= 13
+        FROM boundary_z10 WHERE geom && bbox AND zoom_level >= 13
-    ) AS zoom_levels
+    ) AS zoom_levels;
-    WHERE geom && bbox;
 $$ LANGUAGE SQL IMMUTABLE;

schema/layers/building.sql

@@ -12,12 +12,11 @@ RETURNS TABLE(geom geometry, osm_id bigint, render_height float) AS $$
     least(greatest(3, COALESCE(height, levels*3.66,5)),400)^.7 AS render_height
     FROM (
         SELECT osm_id, ST_Simplify(way, 10) AS way, height, levels FROM building_z13
-        WHERE zoom_level = 13
+        WHERE zoom_level = 13 AND way && bbox
         UNION ALL
         SELECT * FROM building_z14
-        WHERE zoom_level >= 14
+        WHERE zoom_level >= 14 AND way && bbox
     ) AS zoom_levels
-    WHERE way && bbox
     ORDER BY render_height, ST_YMin(way) DESC;
 $$ LANGUAGE SQL IMMUTABLE;