Port latest shutdown hanger bug to 3.5. (#10121)

arangod/Utils/CollectionKeysRepository.cpp

@@ -34,7 +34,7 @@ size_t const CollectionKeysRepository::MaxCollectCount = 32;
 /// @brief create a collection keys repository
 ////////////////////////////////////////////////////////////////////////////////
 
-CollectionKeysRepository::CollectionKeysRepository() : _lock(), _keys() {
+CollectionKeysRepository::CollectionKeysRepository() : _lock(), _keys(), _stopped(false) {
   _keys.reserve(64);
 }
 
@@ -80,8 +80,10 @@ CollectionKeysRepository::~CollectionKeysRepository() {
 
 void CollectionKeysRepository::store(std::unique_ptr<arangodb::CollectionKeys> keys) {
   MUTEX_LOCKER(mutexLocker, _lock);
+  if (!_stopped) {
     _keys.emplace(keys->id(), std::move(keys));
   }
+}
 
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief remove collection keys by id

arangod/Utils/CollectionKeysRepository.h

@@ -26,6 +26,7 @@
 
 #include "Basics/Common.h"
 #include "Basics/Mutex.h"
+#include "Basics/MutexLocker.h"
 #include "Utils/CollectionKeys.h"
 #include "VocBase/voc-types.h"
 
@@ -90,6 +91,15 @@ class CollectionKeysRepository {
 
   bool garbageCollect(bool force);
 
+  //////////////////////////////////////////////////////////////////////////
+  /// @brief stop further stores, this is used on shutdown
+  //////////////////////////////////////////////////////////////////////////
+
+  void stopStores() {
+    MUTEX_LOCKER(mutexLocker, _lock);
+    _stopped = true;
+  }
+
  private:
   //////////////////////////////////////////////////////////////////////////////
   /// @brief mutex for the repository
@@ -108,6 +118,13 @@ class CollectionKeysRepository {
   //////////////////////////////////////////////////////////////////////////////
 
   static size_t const MaxCollectCount;
+
+  ////////////////////////////////////////////////////////////////////////////
+  /// @brief stopped flag, indicating that no more CollectionKeys can be
+  /// stored
+  ////////////////////////////////////////////////////////////////////////////
+
+  bool _stopped;
 };
 }  // namespace arangodb
 

arangod/VocBase/vocbase.cpp

@@ -760,6 +760,7 @@ void TRI_vocbase_t::stop() {
     // soon, we have to retry, since some of these collection keys might currently
     // still being in use:
     auto lastTime = TRI_microtime();
+    _collectionKeys->stopStores();
     while (true) {
       if (!_collectionKeys->garbageCollect(true)) {
         break;