MAGETWO-95294: Mysql search slow on the catalog page

- changes after CR

Author: vgoncharenko

app/code/Magento/CatalogSearch/Model/ResourceModel/Advanced/Collection.php

@@ -266,7 +266,10 @@ public function setOrder($attribute, $dir = Select::SQL_DESC)
      */
     public function addCategoryFilter(\Magento\Catalog\Model\Category $category)
     {
-        /** This changes need in BIC reasons for support dynamic improved algorithm for price aggregation process. */
+        /**
+         * This changes need in backward compatible reasons for support dynamic improved algorithm
+         * for price aggregation process.
+         */
         if ($this->isCurrentEngineMysql()) {
             parent::addCategoryFilter($category);
         } else {
@@ -282,7 +285,10 @@ public function addCategoryFilter(\Magento\Catalog\Model\Category $category)
      */
     public function setVisibility($visibility)
     {
-        /** This changes need in BIC reasons for support dynamic improved algorithm for price aggregation process. */
+        /**
+         * This changes need in backward compatible reasons for support dynamic improved algorithm
+         * for price aggregation process.
+         */
         if ($this->isCurrentEngineMysql()) {
             parent::setVisibility($visibility);
         } else {
@@ -391,6 +397,7 @@ private function getSearchResultApplier(SearchResultInterface $searchResult): Se
         return $this->searchResultApplierFactory->create([
             'collection' => $this,
             'searchResult' => $searchResult,
+            /** This variable sets by serOrder method, but doesn't have a getter method. */
             'orders' => $this->_orders
         ]);
     }

app/code/Magento/CatalogSearch/Model/ResourceModel/Fulltext/Collection.php

@@ -509,6 +509,7 @@ private function getSearchResultApplier(SearchResultInterface $searchResult): Se
         return $this->searchResultApplierFactory->create([
             'collection' => $this,
             'searchResult' => $searchResult,
+            /** This variable sets by serOrder method, but doesn't have a getter method. */
             'orders' => $this->_orders,
         ]);
     }
@@ -584,7 +585,10 @@ public function getFacetedData($field)
     public function addCategoryFilter(\Magento\Catalog\Model\Category $category)
     {
         $this->addFieldToFilter('category_ids', $category->getId());
-        /** This changes need in BIC reasons for support dynamic improved algorithm for price aggregation process. */
+        /**
+         * This changes need in backward compatible reasons for support dynamic improved algorithm
+         * for price aggregation process.
+         */
         if ($this->isCurrentEngineMysql()) {
             parent::addCategoryFilter($category);
         } else {
@@ -603,7 +607,10 @@ public function addCategoryFilter(\Magento\Catalog\Model\Category $category)
     public function setVisibility($visibility)
     {
         $this->addFieldToFilter('visibility', $visibility);
-        /** This changes need in BIC reasons for support dynamic improved algorithm for price aggregation process. */
+        /**
+         * This changes need in backward compatible reasons for support dynamic improved algorithm
+         * for price aggregation process.
+         */
         if ($this->isCurrentEngineMysql()) {
             parent::setVisibility($visibility);
         }