Bugfix: Disable expire in flex output when not used

If we don't have expire enabled we never need to create an expire list.
But as a side effect of the two-stage processing we created such a list
which costs a lot of time and RAM. This commit disables this which
speeds up processing considerably.

See #1436

Author: joto

src/expire-tiles.hpp

@@ -60,6 +60,8 @@ struct expire_tiles
     expire_tiles(uint32_t maxzoom, double maxbbox,
                  const std::shared_ptr<reprojection> &projection);
 
+    bool enabled() const noexcept { return maxzoom != 0; }
+
     int from_bbox(double min_lon, double min_lat, double max_lon,
                   double max_lat);
     void from_wkb(char const *wkb, osmid_t osm_id);

src/output-flex.cpp

@@ -1294,7 +1294,7 @@ void output_flex_t::delete_from_table(table_connection_t *table_connection,
     assert(table_connection);
     auto const id = table_connection->table().map_id(type, osm_id);
 
-    if (table_connection->table().has_geom_column()) {
+    if (m_expire.enabled() && table_connection->table().has_geom_column()) {
         auto const result = table_connection->get_geom_by_id(type, id);
 
         if (result.num_tuples() == 0) {