diff --git a/arangod/Transaction/Manager.cpp b/arangod/Transaction/Manager.cpp
index d2d71784b7..4c27f33939 100644
--- a/arangod/Transaction/Manager.cpp
+++ b/arangod/Transaction/Manager.cpp
@@ -98,30 +98,88 @@ void Manager::shutdown () {
 /// @brief create a transaction object
 ////////////////////////////////////////////////////////////////////////////////
 
-Transaction* Manager::createTransaction (TRI_vocbase_t* vocbase) {
+Transaction* Manager::createTransaction (TRI_vocbase_t* vocbase,
+                                         bool singleOperation) {
   Transaction::IdType id = _generator.next();
 
-  Transaction* transaction = new Transaction(this, id, vocbase);
+  Transaction* transaction = new Transaction(this, id, vocbase, singleOperation);
+  
+  WRITE_LOCKER(_lock);
+  auto it = _transactions.insert(make_pair(id, transaction));
+
+  if (it.first == _transactions.end()) {
+    // couldn't insert transaction
+    delete transaction;
+
+    return nullptr;
+  }
 
   return transaction;
 }
 
+////////////////////////////////////////////////////////////////////////////////
+/// @brief return the status of a transaction
+////////////////////////////////////////////////////////////////////////////////
+
+Transaction::StateType Manager::statusTransaction (Transaction::IdType id) {
+  READ_LOCKER(_lock);
+  
+  auto it = _transactions.find(id);
+  if (it != _transactions.end()) {
+    return (*it).second->state();
+  }
+
+  // unknown transaction. probably already committed
+  return Transaction::StateType::STATE_COMMITTED;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+/// @brief get oldest still running transaction
+////////////////////////////////////////////////////////////////////////////////
+
+TransactionInfo Manager::getOldestRunning () {
+  READ_LOCKER(_lock);
+
+  for (auto it = _transactions.begin(); it != _transactions.end(); ++it) {
+    Transaction* transaction = (*it).second;
+  
+    if (transaction->state() == Transaction::StateType::STATE_BEGUN) {
+      return TransactionInfo(transaction->id(), transaction->elapsedTime());
+    }
+  }
+
+  return TransactionInfo();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+/// @brief remove failed transactions from the failed list
+////////////////////////////////////////////////////////////////////////////////
+
+int Manager::removeFailed (vector<Transaction::IdType> const& ids) {
+  WRITE_LOCKER(_lock);
+
+  for (auto it = ids.begin(); it != ids.end(); ++it) {
+    _transactions.erase(*it);
+  }
+
+  return TRI_ERROR_NO_ERROR;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief begin a transaction
 ////////////////////////////////////////////////////////////////////////////////
 
 int Manager::beginTransaction (Transaction* transaction) {
-  double startTime = TRI_microtime();
-  Transaction::IdType id = transaction->id();
-
   WRITE_LOCKER(_lock);
-  auto it = _transactions.insert(make_pair(id, Transaction::StateType::STATE_BEGUN));
-
-  if (it.first == _transactions.end()) {
-    return TRI_ERROR_INTERNAL;
+  
+  // check the transaction state first
+  if (transaction->state() != Transaction::StateType::STATE_UNINITIALISED) {
+    transaction->setAborted();
+    return TRI_ERROR_TRANSACTION_INTERNAL;
   }
 
-  transaction->setStartTime(startTime);
+  // sets status and start time stamp
+  transaction->setBegun();
 
   return TRI_ERROR_NO_ERROR;
 }
@@ -134,13 +192,25 @@ int Manager::commitTransaction (Transaction* transaction) {
   Transaction::IdType id = transaction->id();
   
   WRITE_LOCKER(_lock);
+  
+  if (transaction->state() != Transaction::StateType::STATE_BEGUN) {
+    // set it to aborted
+    transaction->setAborted();
+    return TRI_ERROR_TRANSACTION_INTERNAL;
+  }
+
+  transaction->setCommitted();
+
   auto it = _transactions.find(id);
 
   if (it == _transactions.end()) {
-    return TRI_ERROR_INTERNAL;
+    // not found
+    return TRI_ERROR_TRANSACTION_INTERNAL;
   }
 
+  // erase it in the list of transactions
   _transactions.erase(id);
+
   return TRI_ERROR_NO_ERROR;
 }
 
@@ -149,33 +219,19 @@ int Manager::commitTransaction (Transaction* transaction) {
 ////////////////////////////////////////////////////////////////////////////////
 
 int Manager::abortTransaction (Transaction* transaction) {
-  Transaction::IdType id = transaction->id();
-  
   WRITE_LOCKER(_lock);
-  auto it = _transactions.find(id);
 
-  if (it == _transactions.end()) {
-    return TRI_ERROR_INTERNAL;
+  if (transaction->state() != Transaction::StateType::STATE_BEGUN) {
+    // TODO: set it to aborted
+    return TRI_ERROR_TRANSACTION_INTERNAL;
   }
 
-  (*it).second = Transaction::StateType::STATE_ABORTED;
+  transaction->setAborted();
+  
+  // leave it in the list of transactions
   return TRI_ERROR_NO_ERROR;
 }
 
-////////////////////////////////////////////////////////////////////////////////
-/// @brief return the status of a transaction
-////////////////////////////////////////////////////////////////////////////////
-
-Transaction::StateType Manager::statusTransaction (Transaction::IdType id) {
-  READ_LOCKER(_lock);
-  
-  auto it = _transactions.find(id);
-  if (it == _transactions.end()) {
-    return Transaction::StateType::STATE_COMMITTED;
-  }
-
-  return (*it).second;
-}
 
 // mode: outline-minor
 // outline-regexp: "/// @brief\\|/// {@inheritDoc}\\|/// @addtogroup\\|/// @page\\|// --SECTION--\\|/// @\\}"
diff --git a/arangod/Transaction/Manager.h b/arangod/Transaction/Manager.h
index f35530b4a1..b77b3c58ed 100644
--- a/arangod/Transaction/Manager.h
+++ b/arangod/Transaction/Manager.h
@@ -84,7 +84,26 @@ namespace triagens {
 /// @brief create a transaction object
 ////////////////////////////////////////////////////////////////////////////////
 
-        Transaction* createTransaction (struct TRI_vocbase_s*);
+        Transaction* createTransaction (struct TRI_vocbase_s*,
+                                        bool);
+
+////////////////////////////////////////////////////////////////////////////////
+/// @brief abort a transaction
+////////////////////////////////////////////////////////////////////////////////
+
+        Transaction::StateType statusTransaction (Transaction::IdType);
+
+////////////////////////////////////////////////////////////////////////////////
+/// @brief get oldest still running transaction
+////////////////////////////////////////////////////////////////////////////////
+
+        TransactionInfo getOldestRunning ();
+
+////////////////////////////////////////////////////////////////////////////////
+/// @brief remove failed transactions from the failed list
+////////////////////////////////////////////////////////////////////////////////
+
+        int removeFailed (std::vector<Transaction::IdType> const&);
 
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief begin a transaction
@@ -104,12 +123,6 @@ namespace triagens {
 
         int abortTransaction (Transaction*);
 
-////////////////////////////////////////////////////////////////////////////////
-/// @brief abort a transaction
-////////////////////////////////////////////////////////////////////////////////
-
-        Transaction::StateType statusTransaction (Transaction::IdType);
-
 // -----------------------------------------------------------------------------
 // --SECTION--                                                 private variables
 // -----------------------------------------------------------------------------
@@ -132,7 +145,7 @@ namespace triagens {
 /// @brief all running or aborted transactions
 ////////////////////////////////////////////////////////////////////////////////
 
-        map<Transaction::IdType, Transaction::StateType> _transactions;
+        map<Transaction::IdType, Transaction*> _transactions;
 
     };
 
diff --git a/arangod/Transaction/Transaction.cpp b/arangod/Transaction/Transaction.cpp
index 16caf72604..b5958a5940 100644
--- a/arangod/Transaction/Transaction.cpp
+++ b/arangod/Transaction/Transaction.cpp
@@ -41,11 +41,13 @@ using namespace triagens::transaction;
 
 Transaction::Transaction (Manager* manager,
                           IdType id,
-                          TRI_vocbase_t* vocbase) 
+                          TRI_vocbase_t* vocbase,
+                          bool singleOperation) 
   : _manager(manager),
     _id(id),
     _state(StateType::STATE_UNINITIALISED),
     _vocbase(vocbase),
+    _singleOperation(singleOperation),
     _operations(),
     _startTime() {
 }
@@ -70,15 +72,7 @@ Transaction::~Transaction () {
 ////////////////////////////////////////////////////////////////////////////////
 
 int Transaction::begin () {
-  if (state() == StateType::STATE_UNINITIALISED &&
-      _manager->beginTransaction(this)) {
-    _state = StateType::STATE_BEGUN;
-
-    return TRI_ERROR_NO_ERROR;
-  }
-
-  this->abort();
-  return TRI_ERROR_TRANSACTION_INTERNAL;
+  return _manager->beginTransaction(this);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -86,15 +80,7 @@ int Transaction::begin () {
 ////////////////////////////////////////////////////////////////////////////////
         
 int Transaction::commit () {
-  if (state() == StateType::STATE_BEGUN && 
-      _manager->commitTransaction(this)) {
-    _state = StateType::STATE_COMMITTED;
-
-    return TRI_ERROR_NO_ERROR;
-  }
-  
-  this->abort();
-  return TRI_ERROR_TRANSACTION_INTERNAL;
+  return _manager->commitTransaction(this);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -102,15 +88,7 @@ int Transaction::commit () {
 ////////////////////////////////////////////////////////////////////////////////
         
 int Transaction::abort () {
-  if (state() == StateType::STATE_BEGUN &&
-      _manager->abortTransaction(this)) {
-    _state = StateType::STATE_ABORTED;
-
-    return TRI_ERROR_NO_ERROR;
-  }
-
-  _state = StateType::STATE_ABORTED;
-  return TRI_ERROR_TRANSACTION_INTERNAL;
+  return _manager->abortTransaction(this);
 }
 
 // Local Variables:
diff --git a/arangod/Transaction/Transaction.h b/arangod/Transaction/Transaction.h
index 0ada2907cf..8640e440f7 100644
--- a/arangod/Transaction/Transaction.h
+++ b/arangod/Transaction/Transaction.h
@@ -44,6 +44,8 @@ namespace triagens {
 
     class Transaction {
 
+      friend class Manager;
+
 // -----------------------------------------------------------------------------
 // --SECTION--                                                          typedefs
 // -----------------------------------------------------------------------------
@@ -87,7 +89,8 @@ namespace triagens {
 
         Transaction (Manager*,
                      IdType,
-                     struct TRI_vocbase_s*);
+                     struct TRI_vocbase_s*,
+                     bool);
 
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief destroy a transaction
@@ -118,11 +121,30 @@ namespace triagens {
         }
 
 ////////////////////////////////////////////////////////////////////////////////
-/// @brief set the transaction start time stamp
+/// @brief is single operation?
 ////////////////////////////////////////////////////////////////////////////////
 
-        inline void setStartTime (double s) {
-          _startTime = s;
+        inline bool singleOperation () const {
+          return _singleOperation;
+        }
+
+////////////////////////////////////////////////////////////////////////////////
+/// @brief get the transaction start time stamp
+////////////////////////////////////////////////////////////////////////////////
+
+        inline double startTime () const {
+          return _startTime;
+        }
+
+////////////////////////////////////////////////////////////////////////////////
+/// @brief get the time since transaction start
+////////////////////////////////////////////////////////////////////////////////
+
+        inline double elapsedTime () const {
+          if (state() == Transaction::StateType::STATE_BEGUN) {
+            return TRI_microtime() - _startTime;
+          }
+          return 0.0;
         }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -149,6 +171,31 @@ namespace triagens {
 
       private:
 
+////////////////////////////////////////////////////////////////////////////////
+/// @brief set a transaction to committed
+////////////////////////////////////////////////////////////////////////////////
+
+        void setBegun () {
+          _startTime = TRI_microtime();
+          _state     = StateType::STATE_BEGUN;
+        }
+
+////////////////////////////////////////////////////////////////////////////////
+/// @brief set a transaction to committed
+////////////////////////////////////////////////////////////////////////////////
+
+        void setCommitted () {
+          _state     = StateType::STATE_COMMITTED;
+        }
+
+////////////////////////////////////////////////////////////////////////////////
+/// @brief set a transaction to aborted
+////////////////////////////////////////////////////////////////////////////////
+
+        void setAborted () {
+          _state     = StateType::STATE_ABORTED;
+        }
+
 // -----------------------------------------------------------------------------
 // --SECTION--                                                 private variables
 // -----------------------------------------------------------------------------
@@ -179,6 +226,12 @@ namespace triagens {
 
         struct TRI_vocbase_s* _vocbase;
 
+////////////////////////////////////////////////////////////////////////////////
+/// @brief whether or not the transaction consists of a single operation
+////////////////////////////////////////////////////////////////////////////////
+
+        bool const _singleOperation;
+
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief transaction operations, per collection
 ////////////////////////////////////////////////////////////////////////////////
@@ -193,6 +246,26 @@ namespace triagens {
 
     };
 
+// -----------------------------------------------------------------------------
+// --SECTION--                                                   TransactionInfo
+// -----------------------------------------------------------------------------
+    
+    struct TransactionInfo {
+      TransactionInfo (Transaction::IdType id, 
+                       double elapsedTime) 
+        : _id(id),
+          _elapsedTime(elapsedTime) {
+      }
+
+      TransactionInfo () 
+        : _id(0),
+          _elapsedTime(0.0) {
+      }
+
+      Transaction::IdType const _id;
+      double const              _elapsedTime;
+    };
+
   }
 }
 
diff --git a/js/apps/system/aardvark/frontend/js/bootstrap/errors.js b/js/apps/system/aardvark/frontend/js/bootstrap/errors.js
index a9842301e6..572a2674d2 100644
--- a/js/apps/system/aardvark/frontend/js/bootstrap/errors.js
+++ b/js/apps/system/aardvark/frontend/js/bootstrap/errors.js
@@ -169,6 +169,7 @@
     "ERROR_TRANSACTION_NESTED"     : { "code" : 1651, "message" : "nested transactions detected" }, 
     "ERROR_TRANSACTION_UNREGISTERED_COLLECTION" : { "code" : 1652, "message" : "unregistered collection used in transaction" }, 
     "ERROR_TRANSACTION_DISALLOWED_OPERATION" : { "code" : 1653, "message" : "disallowed operation inside transaction" }, 
+    "ERROR_TRANSACTION_ABORTED"    : { "code" : 1654, "message" : "transaction aborted" }, 
     "ERROR_USER_INVALID_NAME"      : { "code" : 1700, "message" : "invalid user name" }, 
     "ERROR_USER_INVALID_PASSWORD"  : { "code" : 1701, "message" : "invalid password" }, 
     "ERROR_USER_DUPLICATE"         : { "code" : 1702, "message" : "duplicate user" }, 
diff --git a/js/common/bootstrap/errors.js b/js/common/bootstrap/errors.js
index a9842301e6..572a2674d2 100644
--- a/js/common/bootstrap/errors.js
+++ b/js/common/bootstrap/errors.js
@@ -169,6 +169,7 @@
     "ERROR_TRANSACTION_NESTED"     : { "code" : 1651, "message" : "nested transactions detected" }, 
     "ERROR_TRANSACTION_UNREGISTERED_COLLECTION" : { "code" : 1652, "message" : "unregistered collection used in transaction" }, 
     "ERROR_TRANSACTION_DISALLOWED_OPERATION" : { "code" : 1653, "message" : "disallowed operation inside transaction" }, 
+    "ERROR_TRANSACTION_ABORTED"    : { "code" : 1654, "message" : "transaction aborted" }, 
     "ERROR_USER_INVALID_NAME"      : { "code" : 1700, "message" : "invalid user name" }, 
     "ERROR_USER_INVALID_PASSWORD"  : { "code" : 1701, "message" : "invalid password" }, 
     "ERROR_USER_DUPLICATE"         : { "code" : 1702, "message" : "duplicate user" }, 
diff --git a/lib/BasicsC/errors.dat b/lib/BasicsC/errors.dat
index 38cfaf6c67..537d087849 100755
--- a/lib/BasicsC/errors.dat
+++ b/lib/BasicsC/errors.dat
@@ -224,6 +224,7 @@ ERROR_TRANSACTION_INTERNAL,1650,"internal transaction error","Will be raised whe
 ERROR_TRANSACTION_NESTED,1651,"nested transactions detected","Will be raised when transactions are nested."
 ERROR_TRANSACTION_UNREGISTERED_COLLECTION,1652,"unregistered collection used in transaction","Will be raised when a collection is used in the middle of a transaction but was not registered at transaction start."
 ERROR_TRANSACTION_DISALLOWED_OPERATION,1653,"disallowed operation inside transaction","Will be raised when a disallowed operation is carried out in a transaction."
+ERROR_TRANSACTION_ABORTED,1654,"transaction aborted","Will be raised when a transaction was aborted."
 
 ################################################################################
 ## User management
diff --git a/lib/BasicsC/voc-errors.c b/lib/BasicsC/voc-errors.c
index ca7e7f5469..74babe10c3 100644
--- a/lib/BasicsC/voc-errors.c
+++ b/lib/BasicsC/voc-errors.c
@@ -165,6 +165,7 @@ void TRI_InitialiseErrorMessages (void) {
   REG_ERROR(ERROR_TRANSACTION_NESTED, "nested transactions detected");
   REG_ERROR(ERROR_TRANSACTION_UNREGISTERED_COLLECTION, "unregistered collection used in transaction");
   REG_ERROR(ERROR_TRANSACTION_DISALLOWED_OPERATION, "disallowed operation inside transaction");
+  REG_ERROR(ERROR_TRANSACTION_ABORTED, "transaction aborted");
   REG_ERROR(ERROR_USER_INVALID_NAME, "invalid user name");
   REG_ERROR(ERROR_USER_INVALID_PASSWORD, "invalid password");
   REG_ERROR(ERROR_USER_DUPLICATE, "duplicate user");
diff --git a/lib/BasicsC/voc-errors.h b/lib/BasicsC/voc-errors.h
index b105ea150d..6a1628313a 100644
--- a/lib/BasicsC/voc-errors.h
+++ b/lib/BasicsC/voc-errors.h
@@ -394,6 +394,8 @@ extern "C" {
 /// - 1653: @LIT{disallowed operation inside transaction}
 ///   Will be raised when a disallowed operation is carried out in a
 ///   transaction.
+/// - 1654: @LIT{transaction aborted}
+///   Will be raised when a transaction was aborted.
 /// - 1700: @LIT{invalid user name}
 ///   Will be raised when an invalid user name is used.
 /// - 1701: @LIT{invalid password}
@@ -2111,6 +2113,16 @@ void TRI_InitialiseErrorMessages (void);
 
 #define TRI_ERROR_TRANSACTION_DISALLOWED_OPERATION                        (1653)
 
+////////////////////////////////////////////////////////////////////////////////
+/// @brief 1654: ERROR_TRANSACTION_ABORTED
+///
+/// transaction aborted
+///
+/// Will be raised when a transaction was aborted.
+////////////////////////////////////////////////////////////////////////////////
+
+#define TRI_ERROR_TRANSACTION_ABORTED                                     (1654)
+
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief 1700: ERROR_USER_INVALID_NAME
 ///