fix profiler issues

arangod/Aql/Query.cpp

@@ -1444,9 +1444,12 @@ ExecutionState Query::cleanupPlanAndEngine(int errorCode, VPackBuilder* statsBui
     _engine.reset();
   }
 
-  // as a side-effect, the following call removes the query from the list of currently
-  // running queries
-  _profile.reset();
+  // the following call removes the query from the list of currently
+  // running queries. so whoever fetches that list will not see a Query that
+  // is about to shut down/be destroyed
+  if (_profile != nullptr) {
+    _profile->unregisterFromQueryList();
+  }
 
   // If the transaction was not committed, it is automatically aborted
   _trx = nullptr;

arangod/Aql/QueryProfile.cpp

@@ -44,12 +44,20 @@ QueryProfile::QueryProfile(Query* query)
     it = 0.0;  // reset timers
   }
 
-  auto queryList = query->vocbase().queryList();
-  _tracked = queryList->insert(query);
+  registerInQueryList(query);
 }
 
 /// @brief destroy a profile
 QueryProfile::~QueryProfile() {
+  unregisterFromQueryList();
+}
+
+void QueryProfile::registerInQueryList(Query* query) {
+  auto queryList = query->vocbase().queryList();
+  _tracked = queryList->insert(query);
+}
+
+void QueryProfile::unregisterFromQueryList() noexcept {
   // only remove from list when the query was inserted into it...
   if (_tracked) {
     auto queryList = _query->vocbase().queryList();
@@ -58,6 +66,8 @@ QueryProfile::~QueryProfile() {
       queryList->remove(_query);
     } catch (...) {
     }
+
+    _tracked = false;
   }
 }
 

arangod/Aql/QueryProfile.h

@@ -42,11 +42,14 @@ struct QueryProfile {
   QueryProfile(QueryProfile const&) = delete;
   QueryProfile& operator=(QueryProfile const&) = delete;
 
-  explicit QueryProfile(Query*);
+  explicit QueryProfile(Query* query);
 
   ~QueryProfile();
 
  public:
+  /// @brief unregister the query from the list of queries, if entered
+  void unregisterFromQueryList() noexcept;
+
   double setStateDone(QueryExecutionState::ValueType);
 
   /// @brief sets the absolute end time for an execution state
@@ -59,6 +62,9 @@ struct QueryProfile {
 
   /// @brief convert the profile to VelocyPack
   void toVelocyPack(arangodb::velocypack::Builder&) const;
+  
+ private:
+  void registerInQueryList(Query* query);
 
  private:
   Query* _query;