diff --git a/arangod/V8Server/v8-query.cpp b/arangod/V8Server/v8-query.cpp
index 84e9fed23e..8a010713f3 100644
--- a/arangod/V8Server/v8-query.cpp
+++ b/arangod/V8Server/v8-query.cpp
@@ -1675,6 +1675,10 @@ static v8::Handle<v8::Value> JS_AllQuery (v8::Arguments const& argv) {
 
   const size_t n = docs.size();
   uint32_t count = 0;
+  
+  if (n > 0) {
+    TRI_ASSERT_MAINTAINER(barrier != 0);
+  }
 
   // setup result
   v8::Handle<v8::Object> result = v8::Object::New();
diff --git a/js/common/bootstrap/errors.js b/js/common/bootstrap/errors.js
index ab51956c56..bae0dbdf09 100644
--- a/js/common/bootstrap/errors.js
+++ b/js/common/bootstrap/errors.js
@@ -121,6 +121,7 @@
     "ERROR_TRANSACTION_INTERNAL"   : { "code" : 1653, "message" : "internal transaction error" }, 
     "ERROR_TRANSACTION_UNREGISTERED_COLLECTION" : { "code" : 1654, "message" : "unregistered collection used in transaction" }, 
     "ERROR_TRANSACTION_DISALLOWED_OPERATION" : { "code" : 1655, "message" : "disallowed operation inside a transaction" }, 
+    "ERROR_TRANSACTION_DEADLOCK"   : { "code" : 1656, "message" : "deadlock detected during transaction execution" }, 
     "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" },