arangosh> stmt.explain({ optimizer: { rules: [ "-all", "+remove-redundant-calculations" ] } });
{ 
  "plan" : { 
    "nodes" : [ 
      { 
        "type" : "SingletonNode", 
        "dependencies" : [ ], 
        "id" : 1, 
        "estimatedCost" : 1, 
        "estimatedNrItems" : 1 
      }, 
      { 
        "type" : "EnumerateCollectionNode", 
        "dependencies" : [ 
          1 
        ], 
        "id" : 2, 
        "estimatedCost" : 2, 
        "estimatedNrItems" : 1, 
        "database" : "_system", 
        "collection" : "_users", 
        "outVariable" : { 
          "id" : 0, 
          "name" : "user" 
        }, 
        "random" : false 
      }, 
      { 
        "type" : "CalculationNode", 
        "dependencies" : [ 
          2 
        ], 
        "id" : 3, 
        "estimatedCost" : 3, 
        "estimatedNrItems" : 1, 
        "expression" : { 
          "type" : "compare ==", 
          "subNodes" : [ 
            { 
              "type" : "attribute access", 
              "name" : "user", 
              "subNodes" : [ 
                { 
                  "type" : "reference", 
                  "name" : "user", 
                  "id" : 0 
                } 
              ] 
            }, 
            { 
              "type" : "value", 
              "value" : "root" 
            } 
          ] 
        }, 
        "outVariable" : { 
          "id" : 2, 
          "name" : "1" 
        }, 
        "canThrow" : false, 
        "expressionType" : "simple" 
      }, 
      { 
        "type" : "FilterNode", 
        "dependencies" : [ 
          3 
        ], 
        "id" : 4, 
        "estimatedCost" : 4, 
        "estimatedNrItems" : 1, 
        "inVariable" : { 
          "id" : 2, 
          "name" : "1" 
        } 
      }, 
      { 
        "type" : "ReturnNode", 
        "dependencies" : [ 
          4 
        ], 
        "id" : 5, 
        "estimatedCost" : 5, 
        "estimatedNrItems" : 1, 
        "inVariable" : { 
          "id" : 0, 
          "name" : "user" 
        } 
      } 
    ], 
    "rules" : [ ], 
    "collections" : [ 
      { 
        "name" : "_users", 
        "type" : "read" 
      } 
    ], 
    "variables" : [ 
      { 
        "id" : 2, 
        "name" : "1" 
      }, 
      { 
        "id" : 0, 
        "name" : "user" 
      } 
    ], 
    "estimatedCost" : 5, 
    "estimatedNrItems" : 1 
  }, 
  "warnings" : [ ], 
  "stats" : { 
    "rulesExecuted" : 1, 
    "rulesSkipped" : 21, 
    "plansCreated" : 1 
  } 
}