diff --git a/00-backend/datasource/database.sqlite b/00-backend/datasource/database.sqlite
index 1933a37..34e7fe6 100644
Binary files a/00-backend/datasource/database.sqlite and b/00-backend/datasource/database.sqlite differ
diff --git a/00-backend/src/main/java/de/htwsaar/webshop/repository/entities/Order.java b/00-backend/src/main/java/de/htwsaar/webshop/repository/entities/Order.java
index 01d632e..54e1f50 100644
--- a/00-backend/src/main/java/de/htwsaar/webshop/repository/entities/Order.java
+++ b/00-backend/src/main/java/de/htwsaar/webshop/repository/entities/Order.java
@@ -31,7 +31,7 @@ public class Order {
     @Column(name = "status", nullable = false)
     private OrderStatus status;
 
-    @OneToMany(mappedBy = "order", orphanRemoval = true, fetch = FetchType.EAGER, cascade = CascadeType.ALL, targetEntity = OrderItem.class)
+    @OneToMany(mappedBy = "order", orphanRemoval = true, fetch = FetchType.LAZY, targetEntity = OrderItem.class)
     private List<OrderItem> orderItems;
 
     public OrderModel toModel() {
diff --git a/00-backend/src/main/java/de/htwsaar/webshop/service/impl/OrderServiceImpl.java b/00-backend/src/main/java/de/htwsaar/webshop/service/impl/OrderServiceImpl.java
index c92cb48..494fd65 100644
--- a/00-backend/src/main/java/de/htwsaar/webshop/service/impl/OrderServiceImpl.java
+++ b/00-backend/src/main/java/de/htwsaar/webshop/service/impl/OrderServiceImpl.java
@@ -62,8 +62,8 @@ public class OrderServiceImpl implements OrderService {
                         ArrayList::addAll
                 )
         );
+        log.info("Created Order from Model: {}", order);
         orderItemRepository.saveAll(order.getOrderItems());
-        log.info("Saved OrderItems");
         return order;
     }
 
@@ -94,9 +94,10 @@ public class OrderServiceImpl implements OrderService {
         long lower = fromMilli;
         long upper;
         while (months > 0) {
-            upper = fromMilli + TimeUtil.monthLength(fromMilli);
-            log.info("Getting Orders from {} to {}", lower, upper);
-            orders.put(fromMilli, orderRepository.getOrdersByTimeBetween(lower, upper));
+            upper = lower + TimeUtil.monthLength(lower);
+            List<Order> a = orderRepository.getOrdersByTimeBetween(lower, upper);
+            log.info("Getting Orders from {} to {}: size {}", lower, upper, a.size());
+            orders.put(lower, a);
             lower = upper;
             months--;
         }
diff --git a/00-backend/src/main/java/de/htwsaar/webshop/service/impl/StatisticsServiceImpl.java b/00-backend/src/main/java/de/htwsaar/webshop/service/impl/StatisticsServiceImpl.java
index 197f47b..8a7abca 100644
--- a/00-backend/src/main/java/de/htwsaar/webshop/service/impl/StatisticsServiceImpl.java
+++ b/00-backend/src/main/java/de/htwsaar/webshop/service/impl/StatisticsServiceImpl.java
@@ -11,6 +11,7 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.Map;
 import java.util.function.BinaryOperator;
 import java.util.function.Function;
@@ -26,34 +27,33 @@ public class StatisticsServiceImpl implements StatisticsService {
         this.orderService = orderService;
     }
 
-    //don't ask pls
     //returns Map<unix milli timestamp, Map<Category, T>>
     private <T extends Number> MonthlyCatModel<T> getMonthCategoryMap(Function<OrderItem, T> mappingFunction,
-                                                                      BinaryOperator<T> reduceFunction) {
-        return new MonthlyCatModel<>(
-                orderService.getTimeSortedOrders(TimeUtil.nowMonthsAgo(12), 12).entrySet().stream()
-                        .map(entry -> Map.entry(entry.getKey(),
-                                entry.getValue().stream()
-                                        .map(Order::getOrderItems)
-                                        .reduce(new ArrayList<>(), (l, r) -> {
-                                            l.addAll(r);
-                                            return l;
-                                        })
-                                        .stream()
-                                        .map(orderItem -> Map.entry(orderItem.getArticle().getCategory(), mappingFunction.apply(orderItem)))
-                                        .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, reduceFunction))
-                        ))
-                        .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue))
-        );
+                                                                      BinaryOperator<T> reduceFunction,
+                                                                      T defaultValue) {
+        Map<Long, Map<String, T>> map = new HashMap<>();
+        orderService.getTimeSortedOrders(TimeUtil.nowMonthsAgo(12), 12).forEach( (k,v) -> {
+            log.info("Month {} has {}", k, v.size());
+            map.putIfAbsent(k, new HashMap<>());
+            v.forEach( (order) ->
+                order.getOrderItems().forEach((item) -> {
+                    //log.info("  OrderItem {} has cat {}", item, item.getArticle().getCategory());
+                    map.get(k).putIfAbsent(item.getArticle().getCategory(), defaultValue);
+                    map.get(k).computeIfPresent(item.getArticle().getCategory(), (cat,left ) -> reduceFunction.apply(left, mappingFunction.apply(item)));
+                })
+            );
+            log.info("Month has {} cats", map.get(k).size());
+        });
+        return new MonthlyCatModel<>(map);
     }
 
     @Override
     public MonthlyCatModel<Integer> getSalesVolume() {
-        return getMonthCategoryMap(OrderItem::getAmount, Integer::sum);
+        return getMonthCategoryMap(OrderItem::getAmount, Integer::sum, 0);
     }
 
     @Override
     public MonthlyCatModel<Integer> getSalesRevenue() {
-        return getMonthCategoryMap(item -> item.getArticle().getPrice100(), Integer::sum);
+        return getMonthCategoryMap(item -> item.getArticle().getPrice100(), Integer::sum, 0);
     }
 }