diff --git a/arangod/Aql/AqlValue.cpp b/arangod/Aql/AqlValue.cpp
index 50023f21ab..7f773de6cb 100644
--- a/arangod/Aql/AqlValue.cpp
+++ b/arangod/Aql/AqlValue.cpp
@@ -165,7 +165,7 @@ AqlValue AqlValue::at(int64_t position, bool& mustDestroy,
         }
         if (position >= 0 && position < n) {
           if (doCopy) {
-            mustDestroy = true;
+            mustDestroy = (type() == VPACK_MANAGED);
             return AqlValue(s.at(position));
           }
           // return a reference to an existing slice
@@ -237,7 +237,7 @@ AqlValue AqlValue::getKeyAttribute(arangodb::AqlTransaction* trx,
         VPackSlice found = Transaction::extractKeyFromDocument(s);
         if (!found.isNone()) {
           if (doCopy) {
-            mustDestroy = true;
+            mustDestroy = (type() == VPACK_MANAGED);
             return AqlValue(found);
           }
           // return a reference to an existing slice
@@ -278,7 +278,7 @@ AqlValue AqlValue::getIdAttribute(arangodb::AqlTransaction* trx,
         }
         if (!found.isNone()) {
           if (doCopy) {
-            mustDestroy = true;
+            mustDestroy = (type() == VPACK_MANAGED);
             return AqlValue(found);
           }
           // return a reference to an existing slice
@@ -314,7 +314,7 @@ AqlValue AqlValue::getFromAttribute(arangodb::AqlTransaction* trx,
         VPackSlice found = Transaction::extractFromFromDocument(s);
         if (!found.isNone()) {
           if (doCopy) {
-            mustDestroy = true;
+            mustDestroy = (type() == VPACK_MANAGED);
             return AqlValue(found);
           }
           // return a reference to an existing slice
@@ -350,7 +350,7 @@ AqlValue AqlValue::getToAttribute(arangodb::AqlTransaction* trx,
         VPackSlice found = Transaction::extractToFromDocument(s);
         if (!found.isNone()) {
           if (doCopy) {
-            mustDestroy = true;
+            mustDestroy = (type() == VPACK_MANAGED);
             return AqlValue(found);
           }
           // return a reference to an existing slice
@@ -392,7 +392,7 @@ AqlValue AqlValue::get(arangodb::AqlTransaction* trx,
         }
         if (!found.isNone()) {
           if (doCopy) {
-            mustDestroy = true;
+            mustDestroy = (type() == VPACK_MANAGED);
             return AqlValue(found);
           }
           // return a reference to an existing slice
@@ -434,7 +434,7 @@ AqlValue AqlValue::get(arangodb::AqlTransaction* trx,
         }
         if (!found.isNone()) {
           if (doCopy) {
-            mustDestroy = true;
+            mustDestroy = (type() == VPACK_MANAGED);
             return AqlValue(found);
           }
           // return a reference to an existing slice
diff --git a/arangod/Aql/AttributeAccessor.cpp b/arangod/Aql/AttributeAccessor.cpp
index 12085489e4..93832e2ef3 100644
--- a/arangod/Aql/AttributeAccessor.cpp
+++ b/arangod/Aql/AttributeAccessor.cpp
@@ -32,12 +32,13 @@ using namespace arangodb::aql;
 
 /// @brief create the accessor
 AttributeAccessor::AttributeAccessor(
-    std::vector<std::string> const& attributeParts, Variable const* variable)
+    std::vector<std::string>&& attributeParts, Variable const* variable)
     : _attributeParts(attributeParts),
       _variable(variable),
       _type(EXTRACT_MULTI) {
 
   TRI_ASSERT(_variable != nullptr);
+  TRI_ASSERT(!_attributeParts.empty());
 
   // determine accessor type
   if (_attributeParts.size() == 1) {
diff --git a/arangod/Aql/AttributeAccessor.h b/arangod/Aql/AttributeAccessor.h
index ff9c10367d..42bbbc9c90 100644
--- a/arangod/Aql/AttributeAccessor.h
+++ b/arangod/Aql/AttributeAccessor.h
@@ -38,7 +38,7 @@ struct Variable;
 /// @brief AttributeAccessor
 class AttributeAccessor {
  public:
-  AttributeAccessor(std::vector<std::string> const&, Variable const*);
+  AttributeAccessor(std::vector<std::string>&&, Variable const*);
   ~AttributeAccessor() = default;
 
   /// @brief execute the accessor
diff --git a/arangod/Aql/BasicBlocks.cpp b/arangod/Aql/BasicBlocks.cpp
index 20af995808..017ec3c4b9 100644
--- a/arangod/Aql/BasicBlocks.cpp
+++ b/arangod/Aql/BasicBlocks.cpp
@@ -173,6 +173,8 @@ bool FilterBlock::getBlock(size_t atLeast, size_t atMost) {
 
     _buffer.pop_front();  // Block was useless, just try again
     delete cur;           // free this block
+  
+    throwIfKilled();  // check if we were aborted
   }
 
   return true;
diff --git a/arangod/Aql/ExecutionNode.cpp b/arangod/Aql/ExecutionNode.cpp
index 23a36997b2..d1b962e7cd 100644
--- a/arangod/Aql/ExecutionNode.cpp
+++ b/arangod/Aql/ExecutionNode.cpp
@@ -34,7 +34,6 @@
 #include "Aql/SortNode.h"
 #include "Aql/TraversalNode.h"
 #include "Aql/WalkerWorker.h"
-#include "Basics/StringBuffer.h"
 
 using namespace arangodb::basics;
 using namespace arangodb::aql;
diff --git a/arangod/Aql/Expression.cpp b/arangod/Aql/Expression.cpp
index 640163d27a..912998a40d 100644
--- a/arangod/Aql/Expression.cpp
+++ b/arangod/Aql/Expression.cpp
@@ -346,7 +346,7 @@ void Expression::analyzeExpression() {
         auto v = static_cast<Variable const*>(member->getData());
 
         // specialize the simple expression into an attribute accessor
-        _accessor = new AttributeAccessor(parts, v);
+        _accessor = new AttributeAccessor(std::move(parts), v);
         _type = ATTRIBUTE;
         _built = true;
       }
@@ -769,7 +769,6 @@ AqlValue Expression::executeSimpleExpressionFCall(
   auto member = node->getMemberUnchecked(0);
   TRI_ASSERT(member->type == NODE_TYPE_ARRAY);
 
-  VPackBuilder builder;
   size_t const n = member->numMembers();
 
   VPackFunctionParameters parameters;
@@ -782,9 +781,7 @@ AqlValue Expression::executeSimpleExpressionFCall(
       auto arg = member->getMemberUnchecked(i);
 
       if (arg->type == NODE_TYPE_COLLECTION) {
-        builder.clear();
-        builder.add(VPackValue(arg->getString()));
-        parameters.emplace_back(AqlValue(builder));
+        parameters.emplace_back(AqlValue(arg->getString()));
         destroyParameters.push_back(true);
       } else {
         bool localMustDestroy;
@@ -1356,8 +1353,8 @@ AqlValue Expression::executeSimpleExpressionArithmetic(
     return AqlValue(VelocyPackHelper::ZeroValue());
   }
 
-  VPackBuilder builder;
+  TransactionBuilderLeaser builder(trx);
   mustDestroy = true; // builder = dynamic data
-  builder.add(VPackValue(result));
-  return AqlValue(builder);
+  builder->add(VPackValue(result));
+  return AqlValue(*builder.get());
 }
diff --git a/arangod/Aql/IndexBlock.cpp b/arangod/Aql/IndexBlock.cpp
index e4ff362716..93fbc541e7 100644
--- a/arangod/Aql/IndexBlock.cpp
+++ b/arangod/Aql/IndexBlock.cpp
@@ -533,8 +533,14 @@ AqlItemBlock* IndexBlock::getSome(size_t atLeast, size_t atMost) {
         // we do not need to do a lookup in
         // getPlanNode()->_registerPlan->varInfo,
         // but can just take cur->getNrRegs() as registerId:
-        res->setValue(j, static_cast<arangodb::aql::RegisterId>(curRegs), 
-                      AqlValue(_documents[_posInDocs++]));
+        auto doc = _documents[_posInDocs++];
+        if (doc.isExternal()) {
+          res->setValue(j, static_cast<arangodb::aql::RegisterId>(curRegs), 
+                        AqlValue(doc.resolveExternal().begin()));
+        } else {
+          res->setValue(j, static_cast<arangodb::aql::RegisterId>(curRegs), 
+                        AqlValue(doc));
+        }
         // No harm done, if the setValue throws!
       }
     }
diff --git a/arangod/Aql/OptimizerRules.cpp b/arangod/Aql/OptimizerRules.cpp
index 097d3a7bc3..eb90033920 100644
--- a/arangod/Aql/OptimizerRules.cpp
+++ b/arangod/Aql/OptimizerRules.cpp
@@ -231,8 +231,7 @@ void arangodb::aql::removeRedundantSortsRule(Optimizer* opt,
   }
 
   std::unordered_set<ExecutionNode*> toUnlink;
-
-  arangodb::basics::StringBuffer buffer(TRI_UNKNOWN_MEM_ZONE);
+  arangodb::basics::StringBuffer buffer(TRI_UNKNOWN_MEM_ZONE, false);
 
   for (auto const& n : nodes) {
     if (toUnlink.find(n) != toUnlink.end()) {
@@ -1367,7 +1366,7 @@ void arangodb::aql::removeRedundantCalculationsRule(
     return;
   }
 
-  arangodb::basics::StringBuffer buffer(TRI_UNKNOWN_MEM_ZONE);
+  arangodb::basics::StringBuffer buffer(TRI_UNKNOWN_MEM_ZONE, false);
   std::unordered_map<VariableId, Variable const*> replacements;
 
   for (auto const& n : nodes) {