Clear memory as early as possible.

src/idlist.hpp

@@ -58,6 +58,8 @@ class idlist_t
 
     void clear() noexcept { m_list.clear(); }
 
+    void shrink_to_fit() noexcept { m_list.shrink_to_fit(); }
+
     void push_back(osmid_t id) { m_list.push_back(id); }
 
     void reserve(std::size_t size) { m_list.reserve(size); }

src/osmdata.cpp

@@ -85,6 +85,7 @@ void osmdata_t::after_nodes()
         m_mid->get_node_parents(m_changed_nodes, &m_ways_pending_tracker,
                                 &m_rels_pending_tracker);
         m_changed_nodes.clear();
+        m_changed_nodes.shrink_to_fit();
     }
 }
 
@@ -136,6 +137,7 @@ void osmdata_t::after_ways()
         m_mid->get_way_parents(m_changed_ways, &m_rels_pending_tracker);
 
         m_changed_ways.clear();
+        m_changed_ways.shrink_to_fit();
         return;
     }
 
@@ -183,6 +185,7 @@ void osmdata_t::after_relations()
         m_rels_pending_tracker.remove_ids_if_in(m_changed_relations);
 
         m_changed_relations.clear();
+        m_changed_relations.shrink_to_fit();
     }
 
     m_output->sync();