From cc00bb8897391d15120dc30614f46d1aa14ec1f2 Mon Sep 17 00:00:00 2001
From: Jan Steemann <jan@arangodb.com>
Date: Thu, 4 Dec 2014 16:33:48 +0100
Subject: [PATCH] optimizations

---
 arangod/Aql/AqlItemBlock.h |  9 +++++++++
 arangod/Aql/AqlValue.cpp   | 20 ++++++++++++--------
 lib/Basics/JsonHelper.h    |  8 ++++++++
 3 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/arangod/Aql/AqlItemBlock.h b/arangod/Aql/AqlItemBlock.h
index 79b34c5eb4..e01964998e 100644
--- a/arangod/Aql/AqlItemBlock.h
+++ b/arangod/Aql/AqlItemBlock.h
@@ -103,6 +103,15 @@ namespace triagens {
           TRI_ASSERT(_data.capacity() > index * _nrRegs + varNr);
           return _data[index * _nrRegs + varNr];
         }
+ 
+////////////////////////////////////////////////////////////////////////////////
+/// @brief getValue, get the value of a register by reference
+////////////////////////////////////////////////////////////////////////////////
+
+        AqlValue const& getValueReference (size_t index, RegisterId varNr) const {
+          TRI_ASSERT(_data.capacity() > index * _nrRegs + varNr);
+          return _data[index * _nrRegs + varNr];
+        }
 
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief setValue, set the current value of a register
diff --git a/arangod/Aql/AqlValue.cpp b/arangod/Aql/AqlValue.cpp
index bf8d1cf512..feadd2378c 100644
--- a/arangod/Aql/AqlValue.cpp
+++ b/arangod/Aql/AqlValue.cpp
@@ -756,17 +756,21 @@ AqlValue AqlValue::CreateFromBlocks (triagens::arango::AqlTransaction* trx,
   for (auto it = src.begin(); it != src.end(); ++it) {
     auto current = (*it);
     RegisterId const n = current->getNrRegs();
+    
+    std::vector<std::pair<RegisterId, TRI_document_collection_t const*>> registers;
+    for (RegisterId j = 0; j < n; ++j) {
+      // temporaries don't have a name and won't be included
+      if (variableNames[j][0] != '\0') {
+        registers.emplace_back(std::make_pair(j, current->getDocumentCollection(j)));
+      }
+    }
 
     for (size_t i = 0; i < current->size(); ++i) {
-      Json values(Json::Array);
+      Json values(Json::Array, registers.size());
 
-      for (RegisterId j = 0; j < n; ++j) {
-        if (variableNames[j][0] != '\0') {
-          // temporaries don't have a name and won't be included
-          // Variables from depth 0 are excluded, too, unless the
-          // COLLECT statement is on level 0 as well.
-          values.set(variableNames[j].c_str(), current->getValue(i, j).toJson(trx, current->getDocumentCollection(j)));
-        }
+      // only enumerate the registers that are left
+      for (auto const& reg : registers) {
+        values.set(variableNames[reg.first], current->getValueReference(i, reg.first).toJson(trx, reg.second));
       }
 
       json->add(values);
diff --git a/lib/Basics/JsonHelper.h b/lib/Basics/JsonHelper.h
index eadfcc4d03..aebc246367 100644
--- a/lib/Basics/JsonHelper.h
+++ b/lib/Basics/JsonHelper.h
@@ -702,6 +702,14 @@ namespace triagens {
           TRI_Insert3ArrayJson(_zone, _json, name, sub.steal());
           return *this;
         }
+        
+        Json& set (std::string const& name, Json sub) {
+          if (! TRI_IsArrayJson(_json)) {
+            throw JsonException("Json is no array");
+          }
+          TRI_Insert3ArrayJson(_zone, _json, name.c_str(), sub.steal());
+          return *this;
+        }
 
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief this is a syntactic shortcut for the set method using operator()