fixed issue #1950

arangod/Aql/OptimizerRules.cpp

@@ -1239,12 +1239,12 @@ class arangodb::aql::RedundantCalculationsReplacer final
  public:
   explicit RedundantCalculationsReplacer(
       std::unordered_map<VariableId, Variable const*> const& replacements)
-      : _replacements(replacements) {}
+      : _replacements(replacements) {
+  }
 
   template <typename T>
   void replaceInVariable(ExecutionNode* en) {
     auto node = static_cast<T*>(en);
-
     node->_inVariable = Variable::replace(node->_inVariable, _replacements);
   }
 
@@ -1252,7 +1252,7 @@ class arangodb::aql::RedundantCalculationsReplacer final
     auto node = static_cast<CalculationNode*>(en);
     std::unordered_set<Variable const*> variables;
     node->expression()->variables(variables);
-
+    
     // check if the calculation uses any of the variables that we want to
     // replace
     for (auto const& it : variables) {
@@ -3784,6 +3784,14 @@ void arangodb::aql::inlineSubqueriesRule(Optimizer* opt,
           auto queryVariables = plan->getAst()->variables();
           std::vector<ExecutionNode*> subNodes(subqueryNode->getSubquery()->getDependencyChain(true));
 
+          // check if the subquery result variable is used after the FOR loop as well
+          std::unordered_set<Variable const*> varsUsedLater(listNode->getVarsUsedLater());
+          if (varsUsedLater.find(listNode->inVariable()) != varsUsedLater.end()) {
+            // exit the loop
+            current = nullptr;
+            break;
+          }
+
           TRI_ASSERT(! subNodes.empty());
           auto returnNode = static_cast<ReturnNode*>(subNodes[0]);
           TRI_ASSERT(returnNode->getType() == EN::RETURN);

js/server/modules/@arangodb/aql-helper.js

@@ -469,6 +469,12 @@ function removeClusterNodes (nodeTypes) {
   });
 }
 
+function removeClusterNodesFromPlan (nodes) {
+  return nodes.filter(function (node) {
+    return ([ 'ScatterNode', 'GatherNode', 'DistributeNode', 'RemoteNode' ].indexOf(node.type) === -1);
+  });
+}
+
 exports.isEqual = isEqual;
 exports.getParseResults = getParseResults;
 exports.assertParseError = assertParseError;
@@ -487,3 +493,4 @@ exports.findReferencedNodes = findReferencedNodes;
 exports.getQueryMultiplePlansAndExecutions = getQueryMultiplePlansAndExecutions;
 exports.removeAlwaysOnClusterRules = removeAlwaysOnClusterRules;
 exports.removeClusterNodes = removeClusterNodes;
+exports.removeClusterNodesFromPlan = removeClusterNodesFromPlan;

js/server/tests/aql/aql-optimizer-rule-inline-subqueries.js

@@ -31,14 +31,14 @@
 var jsunity = require("jsunity");
 var helper = require("@arangodb/aql-helper");
 var isEqual = helper.isEqual;
+var db = require("@arangodb").db;
+var ruleName = "inline-subqueries";
 
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief test suite
 ////////////////////////////////////////////////////////////////////////////////
 
 function optimizerRuleTestSuite () {
-  var ruleName = "inline-subqueries";
-
   // various choices to control the optimizer: 
   var paramNone = { optimizer: { rules: [ "-all" ] } };
   var paramEnabled = { optimizer: { rules: [ "-all", "+" + ruleName ] }, inspectSimplePlans: true };
@@ -161,8 +161,73 @@ function optimizerRuleTestSuite () {
         result = AQL_EXECUTE(query[0]).json;
         assertEqual(query[1], result, query);
       });
+    }
+
+  };
+}
+
+////////////////////////////////////////////////////////////////////////////////
+/// @brief test suite
+////////////////////////////////////////////////////////////////////////////////
+
+function optimizerRuleCollectionTestSuite () {
+  var c = null;
+  var cn = "UnitTestsOptimizer";
+
+  return {
+
+    ////////////////////////////////////////////////////////////////////////////////
+    /// @brief set up
+    ////////////////////////////////////////////////////////////////////////////////
+
+    setUp : function () {
+      db._drop(cn);
+      c = db._create(cn);
     },
 
+    ////////////////////////////////////////////////////////////////////////////////
+    /// @brief tear down
+    ////////////////////////////////////////////////////////////////////////////////
+
+    tearDown : function () {
+      db._drop(cn);
+      c = null;
+    },
+
+    testSpecificPlan1 : function () {
+      var query = "LET x = (FOR doc IN @@cn RETURN doc) FOR doc2 IN x RETURN doc2";
+
+      var result = AQL_EXPLAIN(query, { "@cn" : cn });
+      assertNotEqual(-1, result.plan.rules.indexOf(ruleName), query);
+      var nodes = helper.removeClusterNodesFromPlan(result.plan.nodes);
+      assertEqual(3, nodes.length);
+      assertEqual("ReturnNode", nodes[nodes.length - 1].type);
+      assertEqual("doc2", nodes[nodes.length - 1].inVariable.name);
+      assertEqual("EnumerateCollectionNode", nodes[nodes.length - 2].type);
+      assertEqual(cn, nodes[nodes.length - 2].collection);
+    },
+
+    testSpecificPlan2 : function () {
+      var query = "LET x = (FOR doc IN @@cn FILTER doc.foo == 'bar' RETURN doc) FOR doc2 IN x RETURN doc2";
+
+      var result = AQL_EXPLAIN(query, { "@cn" : cn });
+      assertNotEqual(-1, result.plan.rules.indexOf(ruleName), query);
+      var nodes = helper.removeClusterNodesFromPlan(result.plan.nodes);
+      assertEqual(5, nodes.length);
+      assertEqual("ReturnNode", nodes[nodes.length - 1].type);
+      assertEqual("doc2", nodes[nodes.length - 1].inVariable.name);
+      assertEqual("FilterNode", nodes[nodes.length - 2].type);
+      assertEqual("CalculationNode", nodes[nodes.length - 3].type);
+      assertEqual("EnumerateCollectionNode", nodes[nodes.length - 4].type);
+      assertEqual(cn, nodes[nodes.length - 4].collection);
+    },
+
+    testSpecificPlan3 : function () {
+      var query = "LET x = (FOR doc IN @@cn RETURN doc) FOR doc2 IN x RETURN x";
+      var result = AQL_EXPLAIN(query, { "@cn" : cn });
+      assertEqual(-1, result.plan.rules.indexOf(ruleName), query); // no optimization
+    }
+
   };
 }
 
@@ -171,5 +236,6 @@ function optimizerRuleTestSuite () {
 ////////////////////////////////////////////////////////////////////////////////
 
 jsunity.run(optimizerRuleTestSuite);
+jsunity.run(optimizerRuleCollectionTestSuite);
 
 return jsunity.done();