diff --git a/webapp/controller/ShopController.class.php b/webapp/controller/ShopController.class.php
index fdea0e17..6bb9778b 100644
--- a/webapp/controller/ShopController.class.php
+++ b/webapp/controller/ShopController.class.php
@@ -706,6 +706,8 @@ class ShopController extends BaseAuthedController
         $price = $this->normalizeWeb3Price($num);
         $item_id = V_ITEM_DIAMOND;
         $item_count = $num;
+        
+        error_log("buy diamond start " . $num);
 
         $response = services\BlockChainService::gameItemMallBuy(
             Transaction::BUY_GOODS_ACTION_TYPE,