fix shutdown order

arangod/Cluster/ClusterFeature.cpp

@@ -58,6 +58,7 @@ ClusterFeature::ClusterFeature(application_features::ApplicationServer* server)
   setOptional(true);
   requiresElevatedPrivileges(false);
   startsAfter("Authentication");
+  startsAfter("CacheManager");
   startsAfter("Logger");
   startsAfter("WorkMonitor");
   startsAfter("Database");
@@ -571,6 +572,8 @@ void ClusterFeature::unprepare() {
 
   AgencyCommManager::MANAGER->stop();
   ClusterComm::cleanup();
+
+  ClusterInfo::cleanup();
 }
 
 void ClusterFeature::setUnregisterOnShutdown(bool unregisterOnShutdown) {

arangod/Cluster/ClusterInfo.cpp

@@ -213,6 +213,23 @@ ClusterInfo::ClusterInfo(AgencyCallbackRegistry* agencyCallbackRegistry)
 ////////////////////////////////////////////////////////////////////////////////
 
 ClusterInfo::~ClusterInfo() {}
+  
+////////////////////////////////////////////////////////////////////////////////
+/// @brief cleanup method which frees cluster-internal shared ptrs on shutdown
+////////////////////////////////////////////////////////////////////////////////
+
+void ClusterInfo::cleanup() {
+  ClusterInfo* theInstance = instance();
+  if (theInstance == nullptr) {
+    return;
+  }
+
+  theInstance->_plannedCollections.clear();
+  theInstance->_shards.clear();
+  theInstance->_shardKeys.clear();
+  theInstance->_shardIds.clear();
+  theInstance->_currentCollections.clear();
+}
 
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief increase the uniqid value. if it exceeds the upper bound, fetch a

arangod/Cluster/ClusterInfo.h

@@ -251,6 +251,12 @@ class ClusterInfo {
   //////////////////////////////////////////////////////////////////////////////
 
   static ClusterInfo* instance();
+  
+  //////////////////////////////////////////////////////////////////////////////
+  /// @brief cleanup method which frees cluster-internal shared ptrs on shutdown
+  //////////////////////////////////////////////////////////////////////////////
+
+  static void cleanup();
 
  public:
   //////////////////////////////////////////////////////////////////////////////