From 1769299e9536b41c6b549626ae0ef617ce13e4be Mon Sep 17 00:00:00 2001
From: Jan Steemann <jan@arangodb.com>
Date: Mon, 4 Jul 2016 16:30:04 +0200
Subject: [PATCH] make optimizer not skip "use-indexes-rule", even if enough
 plans have been created already

---
 arangod/Aql/AstNode.cpp   |  4 ++++
 arangod/Aql/Condition.cpp |  8 ++++++++
 arangod/Aql/Optimizer.cpp | 10 +++++++---
 3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/arangod/Aql/AstNode.cpp b/arangod/Aql/AstNode.cpp
index ab590cf45c..241d24baa1 100644
--- a/arangod/Aql/AstNode.cpp
+++ b/arangod/Aql/AstNode.cpp
@@ -871,6 +871,10 @@ void AstNode::dump(int level) const {
   if (type == NODE_TYPE_VALUE || type == NODE_TYPE_ARRAY) {
     std::unique_ptr<TRI_json_t> json(toJsonValue(TRI_UNKNOWN_MEM_ZONE));
     std::cout << ": " << json.get();
+  } else if (type == NODE_TYPE_ATTRIBUTE_ACCESS) {
+    std::cout << ": " << getString();
+  } else if (type == NODE_TYPE_REFERENCE) {
+    std::cout << ": " << static_cast<Variable const*>(getData())->name;
   }
   std::cout << "\n";
 
diff --git a/arangod/Aql/Condition.cpp b/arangod/Aql/Condition.cpp
index 4c669fd1ac..20eb2565d9 100644
--- a/arangod/Aql/Condition.cpp
+++ b/arangod/Aql/Condition.cpp
@@ -194,6 +194,14 @@ bool ConditionPart::isCoveredBy(ConditionPart const& other, bool isReversed) con
     }
   }
 
+  TRI_ASSERT(valueNode != nullptr);
+  TRI_ASSERT(other.valueNode != nullptr);
+  
+  if (!valueNode->isConstant() || !other.valueNode->isConstant()) {
+    return false;
+  }
+
+
   // special cases for IN...
   if (!isExpanded && !other.isExpanded &&
       other.operatorType == NODE_TYPE_OPERATOR_BINARY_IN &&
diff --git a/arangod/Aql/Optimizer.cpp b/arangod/Aql/Optimizer.cpp
index b46b9073bc..0fb23971fd 100644
--- a/arangod/Aql/Optimizer.cpp
+++ b/arangod/Aql/Optimizer.cpp
@@ -146,9 +146,13 @@ int Optimizer::createPlans(ExecutionPlan* plan,
         level = (*it).first;
         auto& rule = (*it).second;
 
+        // skip over rules if we should
+        // however, we don't want to skip the "use-indexes" rule when it
+        // was not explicitly deactivated by the caller
         if ((runOnlyRequiredRules ||
              disabledIds.find(level) != disabledIds.end()) &&
-            rule.canBeDisabled) {
+            rule.canBeDisabled &&
+            (!runOnlyRequiredRules || rule.name != "use-indexes")) { 
           // we picked a disabled rule or we have reached the max number of
           // plans
           // and just skip this rule
@@ -299,7 +303,7 @@ std::unordered_set<int> Optimizer::getDisabledRuleIds(
         }
       } else {
         // disable a specific rule
-        auto it = _ruleLookup.find(std::string(name.c_str() + 1));
+        auto it = _ruleLookup.find(name.c_str() + 1);
 
         if (it != _ruleLookup.end()) {
           disabled.emplace((*it).second);
@@ -311,7 +315,7 @@ std::unordered_set<int> Optimizer::getDisabledRuleIds(
         // enable all rules
         disabled.clear();
       } else {
-        auto it = _ruleLookup.find(std::string(name.c_str() + 1));
+        auto it = _ruleLookup.find(name.c_str() + 1);
 
         if (it != _ruleLookup.end()) {
           disabled.erase((*it).second);