diff --git a/arangod/Aql/ExecutionPlan.cpp b/arangod/Aql/ExecutionPlan.cpp
index cc5ef89d42..f1de375758 100644
--- a/arangod/Aql/ExecutionPlan.cpp
+++ b/arangod/Aql/ExecutionPlan.cpp
@@ -27,6 +27,8 @@
 
 #include "Aql/ExecutionPlan.h"
 
+#include <Basics/JsonHelper.h>
+
 using namespace triagens::aql;
 
 // -----------------------------------------------------------------------------
@@ -38,12 +40,95 @@ using namespace triagens::aql;
 ////////////////////////////////////////////////////////////////////////////////
 
 TRI_json_t* ExecutionPlan::toJson (TRI_memory_zone_t* zone) {
-  TRI_json_t* json = TRI_CreateArray2Json(zone, 1);
-  TRI_json_t* sub = TRI_CreateStringCopyJson(zone, "ILLEGAL");
-  TRI_Insert2ArrayJson(zone, json, "type", sub);
+  TRI_json_t* json = TRI_CreateArray2Json(zone, 2);
+  if (nullptr == json) {
+    return nullptr;
+  }
+
+  std::string type = getTypeString();
+  TRI_json_t* sub = TRI_CreateString2CopyJson(zone, type.c_str(), type.size());
+  if (nullptr == sub) {
+    TRI_FreeJson(zone, json);
+    return nullptr;
+  }
+  TRI_Insert3ArrayJson(zone, json, "type", sub);
+
+  if (_dependencies.size() != 0) {
+    sub = TRI_CreateList2Json(zone, _dependencies.size());
+    if (nullptr == sub) {
+      TRI_FreeJson(zone, json);
+      return nullptr;
+    }
+    for (size_t i = 0; i < _dependencies.size(); i++) {
+      TRI_json_t* subsub = _dependencies[i]->toJson(zone);
+      if (subsub == nullptr) {
+        TRI_FreeJson(zone, json);
+        return nullptr;
+      }
+      TRI_PushBack3ListJson(zone, sub, subsub);
+    }
+    TRI_Insert3ArrayJson(zone, json, "dependencies", sub);
+  }
   return json;
 }
 
+////////////////////////////////////////////////////////////////////////////////
+/// @brief convert to a string, basically for debugging purposes
+////////////////////////////////////////////////////////////////////////////////
+
+static void someSpaces (std::string& st, int nr) {
+  for (int i = 0; i < nr; i++) {
+    st.push_back(' ');
+  }
+}
+
+void ExecutionPlan::appendAsString (std::string& st, int indent) {
+  someSpaces(st, indent);
+  st.push_back('<');
+  st.append(getTypeString());
+  if (_dependencies.size() != 0) {
+    st.push_back('\n');
+    for (size_t i = 0; i < _dependencies.size(); i++) {
+      _dependencies[i]->appendAsString(st, indent+2);
+      if (i != _dependencies.size()-1) {
+        st.push_back(',');
+      }
+      else {
+        st.push_back(' ');
+      }
+    }
+  }
+  st.push_back('>');
+}
+
+////////////////////////////////////////////////////////////////////////////////
+/// @brief test function
+////////////////////////////////////////////////////////////////////////////////
+
+void testExecutionPlans () {
+  ExecutionPlan* e = new ExecutionPlan();
+  ExecutionPlan* f = new ExecutionPlan(e);
+  std::string st;
+  e->appendAsString(st, 0);
+  std::cout << "e as string:\n" << st << std::endl;
+  st.clear();
+  f->appendAsString(st, 0);
+  std::cout << "f as string:\n" << st << std::endl;
+  TRI_json_t* json = e->toJson(TRI_UNKNOWN_MEM_ZONE);
+  if (json != nullptr) {
+    std::cout << "e as JSON:\n" << 
+              triagens::basics::JsonHelper::toString(json) << std::endl;
+  }
+  TRI_FreeJson(TRI_UNKNOWN_MEM_ZONE, json);
+  json = f->toJson(TRI_UNKNOWN_MEM_ZONE);
+  if (json != nullptr) {
+    std::cout << "f as JSON:\n" << 
+              triagens::basics::JsonHelper::toString(json) << std::endl;
+  }
+  TRI_FreeJson(TRI_UNKNOWN_MEM_ZONE, json);
+  delete f;  // should not leave a leak
+}
+
 // Local Variables:
 // mode: outline-minor
 // outline-regexp: "^\\(/// @brief\\|/// {@inheritDoc}\\|/// @addtogroup\\|// --SECTION--\\|/// @\\}\\)"
diff --git a/arangod/Aql/ExecutionPlan.h b/arangod/Aql/ExecutionPlan.h
index 1088430e0f..e3bbae9266 100644
--- a/arangod/Aql/ExecutionPlan.h
+++ b/arangod/Aql/ExecutionPlan.h
@@ -112,6 +112,14 @@ namespace triagens {
           return ILLEGAL;
         }
 
+////////////////////////////////////////////////////////////////////////////////
+/// @brief return the type of the node as a string
+////////////////////////////////////////////////////////////////////////////////
+
+        virtual std::string getTypeString () {
+          return std::string("ExecutionPlan (abstract)");
+        }
+
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief add a dependency
 ////////////////////////////////////////////////////////////////////////////////
@@ -145,7 +153,9 @@ namespace triagens {
 /// @brief clone execution plan recursively, this makes the class abstract
 ////////////////////////////////////////////////////////////////////////////////
 
-        virtual ExecutionPlan* clone () = 0;
+        virtual ExecutionPlan* clone () { // = 0;   make this abstract later
+          return this;
+        }
 
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief export to JSON
@@ -153,6 +163,12 @@ namespace triagens {
 
         virtual TRI_json_t* toJson (TRI_memory_zone_t* zone);
 
+////////////////////////////////////////////////////////////////////////////////
+/// @brief convert to a string, basically for debugging purposes
+////////////////////////////////////////////////////////////////////////////////
+
+        virtual void appendAsString (std::string& st, int indent = 0);
+
 // -----------------------------------------------------------------------------
 // --SECTION--                                                 private variables
 // -----------------------------------------------------------------------------