19117: fix performance leak in salesrule collection

Github Issue: #19117

Refactored sql query that created a huge temporary table for each request, when a greater amount of salesrules
and coupon codes exists in database. The sorting of this table took a lot of cpu time.
The statement now consists of two subselects that drill down the remaining lines as far as possible, so that
the remaining temporary table is minimal and easily sorted.

example:
for 2,000 salesrules and 3,000,000 coupon codes the original query took about 2.4 seconds (mbp, server, aws).
the optimized query takes about 5ms (about 100ms on aws).

Author: david-fuehr

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

@@ -107,12 +107,15 @@ protected function mapAssociatedEntities($entityType, $objectField)
 
         $associatedEntities = $this->getConnection()->fetchAll($select);
 
-        array_map(function ($associatedEntity) use ($entityInfo, $ruleIdField, $objectField) {
-            $item = $this->getItemByColumnValue($ruleIdField, $associatedEntity[$ruleIdField]);
-            $itemAssociatedValue = $item->getData($objectField) === null ? [] : $item->getData($objectField);
-            $itemAssociatedValue[] = $associatedEntity[$entityInfo['entity_id_field']];
-            $item->setData($objectField, $itemAssociatedValue);
-        }, $associatedEntities);
+        array_map(
+            function ($associatedEntity) use ($entityInfo, $ruleIdField, $objectField) {
+                $item = $this->getItemByColumnValue($ruleIdField, $associatedEntity[$ruleIdField]);
+                $itemAssociatedValue = $item->getData($objectField) === null ? [] : $item->getData($objectField);
+                $itemAssociatedValue[] = $associatedEntity[$entityInfo['entity_id_field']];
+                $item->setData($objectField, $itemAssociatedValue);
+            },
+            $associatedEntities
+        );
     }
 
     /**
@@ -144,6 +147,7 @@ protected function _afterLoad()
      * @use $this->addWebsiteGroupDateFilter()
      * @SuppressWarnings(PHPMD.UnusedFormalParameter)
      * @return $this
+     * @throws \Zend_Db_Select_Exception
      */
     public function setValidationFilter(
         $websiteId,
@@ -153,32 +157,21 @@ public function setValidationFilter(
         Address $address = null
     ) {
         if (!$this->getFlag('validation_filter')) {
-            /* We need to overwrite joinLeft if coupon is applied */
-            $this->getSelect()->reset();
-            parent::_initSelect();
 
-            $this->addWebsiteGroupDateFilter($websiteId, $customerGroupId, $now);
-            $select = $this->getSelect();
+            $this->prepareSelect($websiteId, $customerGroupId, $now);
 
-            $connection = $this->getConnection();
-            if (strlen($couponCode)) {
-                $noCouponWhereCondition = $connection->quoteInto(
-                    'main_table.coupon_type = ?',
-                    \Magento\SalesRule\Model\Rule::COUPON_TYPE_NO_COUPON
-                );
-                $relatedRulesIds = $this->getCouponRelatedRuleIds($couponCode);
-
-                $select->where(
-                    $noCouponWhereCondition . ' OR main_table.rule_id IN (?)',
-                    $relatedRulesIds,
-                    Select::TYPE_CONDITION
-                );
+            $noCouponRules = $this->getNoCouponCodeSelect();
+
+            if ($couponCode) {
+                $couponRules = $this->getCouponCodeSelect($couponCode);
+                $allAllowedRules = $this->getConnection()->select();
+                $allAllowedRules->union([$noCouponRules, $couponRules], \Zend_Db_Select::SQL_UNION_ALL);
+
+                $this->_select = $allAllowedRules;
             } else {
-                $this->addFieldToFilter(
-                    'main_table.coupon_type',
-                    \Magento\SalesRule\Model\Rule::COUPON_TYPE_NO_COUPON
-                );
+                $this->_select = $noCouponRules;
             }
+
             $this->setOrder('sort_order', self::SORT_ORDER_ASC);
             $this->setFlag('validation_filter', true);
         }
@@ -187,72 +180,96 @@ public function setValidationFilter(
     }
 
     /**
-     * Get rules ids related to coupon code
+     * Recreate the default select object for specific needs of salesrule evaluation with coupon codes.
      *
-     * @param string $couponCode
-     * @return array
+     * @param $websiteId
+     * @param $customerGroupId
+     * @param $now
      */
-    private function getCouponRelatedRuleIds(string $couponCode): array
+    private function prepareSelect($websiteId, $customerGroupId, $now)
     {
-        $connection = $this->getConnection();
-        $select = $connection->select()->from(
-            ['main_table' => $this->getTable('salesrule')],
-            'rule_id'
+        $this->getSelect()->reset();
+        parent::_initSelect();
+
+        $this->addWebsiteGroupDateFilter($websiteId, $customerGroupId, $now);
+    }
+
+    /**
+     * Return select object to determine all active rules not needing a coupon code.
+     *
+     * @return Select
+     */
+    private function getNoCouponCodeSelect()
+    {
+        $noCouponSelect = clone $this->getSelect();
+
+        $noCouponSelect->where(
+            'main_table.coupon_type = ?',
+            Rule::COUPON_TYPE_NO_COUPON
         );
-        $select->joinLeft(
-            ['rule_coupons' => $this->getTable('salesrule_coupon')],
-            $connection->quoteInto(
-                'main_table.rule_id = rule_coupons.rule_id AND main_table.coupon_type != ?',
-                \Magento\SalesRule\Model\Rule::COUPON_TYPE_NO_COUPON,
-                null
-            )
+
+        $noCouponSelect->columns([Coupon::KEY_CODE => new \Zend_Db_Expr('NULL')]);
+
+        return $noCouponSelect;
+    }
+
+    /**
+     * Determine all active rules that are valid for the given coupon code.
+     *
+     * @param $couponCode
+     * @return Select
+     */
+    private function getCouponCodeSelect($couponCode)
+    {
+        $couponSelect = clone $this->getSelect();
+
+        $this->joinCouponTable($couponCode, $couponSelect);
+
+        $notExpired = $this->getConnection()->quoteInto(
+            '(rule_coupons.expiration_date IS NULL OR rule_coupons.expiration_date >= ?)',
+            $this->_date->date()->format('Y-m-d')
         );
 
-        $autoGeneratedCouponCondition = [
-            $connection->quoteInto(
-                "main_table.coupon_type = ?",
-                \Magento\SalesRule\Model\Rule::COUPON_TYPE_AUTO
-            ),
-            $connection->quoteInto(
-                "rule_coupons.type = ?",
-                \Magento\SalesRule\Api\Data\CouponInterface::TYPE_GENERATED
-            ),
-        ];
-
-        $orWhereConditions = [
-            "(" . implode($autoGeneratedCouponCondition, " AND ") . ")",
-            $connection->quoteInto(
-                '(main_table.coupon_type = ? AND main_table.use_auto_generation = 1 AND rule_coupons.type = 1)',
-                \Magento\SalesRule\Model\Rule::COUPON_TYPE_SPECIFIC
-            ),
-            $connection->quoteInto(
-                '(main_table.coupon_type = ? AND main_table.use_auto_generation = 0 AND rule_coupons.type = 0)',
-                \Magento\SalesRule\Model\Rule::COUPON_TYPE_SPECIFIC
-            ),
-        ];
-
-        $andWhereConditions = [
-            $connection->quoteInto(
-                'rule_coupons.code = ?',
-                $couponCode
-            ),
-            $connection->quoteInto(
-                '(rule_coupons.expiration_date IS NULL OR rule_coupons.expiration_date >= ?)',
-                $this->_date->date()->format('Y-m-d')
-            ),
-        ];
-
-        $orWhereCondition = implode(' OR ', $orWhereConditions);
-        $andWhereCondition = implode(' AND ', $andWhereConditions);
-
-        $select->where(
-            '(' . $orWhereCondition . ') AND ' . $andWhereCondition,
+        $isAutogeneratedCoupon =
+            $this->getConnection()->quoteInto('main_table.coupon_type = ?', Rule::COUPON_TYPE_AUTO)
+            . ' AND ' .
+            $this->getConnection()->quoteInto('rule_coupons.type = ?', CouponInterface::TYPE_GENERATED);
+
+        $isValidSpecificCoupon =
+            $this->getConnection()->quoteInto('(main_table.coupon_type = ?)', Rule::COUPON_TYPE_SPECIFIC)
+            . ' AND (' .
+            '(main_table.use_auto_generation = 1 AND rule_coupons.type = 1)'
+            . ' OR ' .
+            '(main_table.use_auto_generation = 0 AND rule_coupons.type = 0)'
+            . ')';
+
+        $couponSelect->where(
+            "$notExpired AND ($isAutogeneratedCoupon OR $isValidSpecificCoupon)",
             null,
             Select::TYPE_CONDITION
         );
-        $select->group('main_table.rule_id');
 
-        return $connection->fetchCol($select);
+        return $couponSelect;
+    }
+
+    /**
+     * @param $couponCode
+     * @param Select $couponSelect
+     */
+    private function joinCouponTable($couponCode, Select $couponSelect)
+    {
+        $couponJoinCondition =
+            'main_table.rule_id = rule_coupons.rule_id'
+            . ' AND ' .
+            $this->getConnection()->quoteInto('main_table.coupon_type <> ?', Rule::COUPON_TYPE_NO_COUPON)
+            . ' AND ' .
+            $this->getConnection()->quoteInto('rule_coupons.code = ?', $couponCode);
+
+        $couponSelect->joinInner(
+            ['rule_coupons' => $this->getTable('salesrule_coupon')],
+            $couponJoinCondition,
+            [Coupon::KEY_CODE]
+        );
     }
 
     /**