Dump some stats about memory usage of cache to debug log

src/middle-pgsql.cpp

@@ -1258,6 +1258,8 @@ void middle_pgsql_t::after_nodes()
         auto const &table = m_tables.nodes();
         analyze_table(m_db_connection, table.schema(), table.name());
     }
+
+    m_cache->log_stats();
 }
 
 void middle_pgsql_t::after_ways()

src/middle-ram.cpp

@@ -190,6 +190,16 @@ void middle_ram_t::relation(osmium::Relation const &relation)
     }
 }
 
+void middle_ram_t::after_nodes()
+{
+    assert(m_middle_state == middle_state::node);
+#ifndef NDEBUG
+    m_middle_state = middle_state::way;
+#endif
+
+    m_node_locations.log_stats();
+}
+
 osmium::Location middle_ram_t::get_node_location(osmid_t id) const
 {
     return m_node_locations.get(id);

src/middle-ram.hpp

@@ -60,6 +60,8 @@ class middle_ram_t : public middle_t, public middle_query_t
     void way(osmium::Way const &way) override;
     void relation(osmium::Relation const &) override;
 
+    void after_nodes() override;
+
     osmium::Location get_node_location(osmid_t id) const override;
 
     std::size_t nodes_get_list(osmium::WayNodeList *nodes) const override;

src/node-locations.cpp

@@ -9,6 +9,8 @@
 
 #include "node-locations.hpp"
 
+#include "logging.hpp"
+
 // Workaround: This must be included before buffer_string.hpp due to a missing
 // include in the upstream code. https://github.com/mapbox/protozero/pull/104
 #include <protozero/config.hpp>
@@ -79,6 +81,17 @@ osmium::Location node_locations_t::get(osmid_t id) const
     return osmium::Location{};
 }
 
+void node_locations_t::log_stats()
+{
+    constexpr auto const mbyte = 1024 * 1024;
+    log_debug("Node locations cache:");
+    log_debug("  num locations stored: {}", m_count);
+    log_debug("  bytes overall: {}MB", used_memory() / mbyte);
+    log_debug("  data capacity: {}MB", m_data.capacity() / mbyte);
+    log_debug("  data size: {}MB", m_data.size() / mbyte);
+    log_debug("  index used memory: {}MB", m_index.used_memory() / mbyte);
+}
+
 void node_locations_t::clear()
 {
     m_data.clear();

src/node-locations.hpp

@@ -71,6 +71,9 @@ class node_locations_t
         return m_data.capacity() + m_index.used_memory();
     }
 
+    /// Dump information about memory usage to debug log
+    void log_stats();
+
     /**
      * Clear the memory used by this object. The object can be reused after
      * that.