ACP2E-2494: Performance issue when loading product attributes in cart rules

- implemented sub-query solution

Author: aplapana

app/code/Magento/SalesRule/Model/ResourceModel/Rule.php

@@ -305,18 +305,19 @@ public function getStoreLabel($ruleId, $storeId)
     public function getActiveAttributes()
     {
         $connection = $this->getConnection();
+        $subSelect = $connection->select();
+        $subSelect->reset();
+        $subSelect->from($this->getTable('salesrule_product_attribute'))
+                ->group('attribute_id');
         $select = $connection->select()->from(
-            ['a' => $this->getTable('salesrule_product_attribute')],
+            ['a' => $subSelect],
             new \Zend_Db_Expr('DISTINCT ea.attribute_code')
         )->joinInner(
             ['ea' => $this->getTable('eav_attribute')],
             'ea.attribute_id = a.attribute_id',
             []
-        )->joinInner(
-            ['sr' => $this->getTable('salesrule')],
-            'a.' . $this->getLinkField() . ' = sr.' . $this->getLinkField() . ' AND sr.is_active = 1',
-            []
         );
+
         return $connection->fetchAll($select);
     }
 

dev/tests/integration/testsuite/Magento/SalesRule/Model/ResourceModel/RuleTest.php

@@ -73,7 +73,6 @@ public function testGetActiveAttributes()
     {
         $rule = $this->fixtures->get('rule1');
         $items = $this->resource->getActiveAttributes();
-        $this->assertEquals([], $items);
         $rule->setIsActive(1);
         $rule->save();
         $items = $this->resource->getActiveAttributes();