Merge pull request #430 from magento-performance/MAGETWO-54645

Fixed issue:
 - MAGETWO-54645: Smarter Cache Invalidation on Qty Change

Author: Oleksii Korshenko

app/code/Magento/CatalogInventory/Block/Stockqty/AbstractStockqty.php

@@ -15,6 +15,8 @@ abstract class AbstractStockqty extends \Magento\Framework\View\Element\Template
 {
     /**
      * Threshold qty config path
+     * @deprecated
+     * @see \Magento\CatalogInventory\Model\Configuration::XML_PATH_STOCK_THRESHOLD_QTY
      */
     const XML_PATH_STOCK_THRESHOLD_QTY = 'cataloginventory/options/stock_threshold_qty';
 

app/code/Magento/CatalogInventory/Model/Configuration.php

@@ -96,6 +96,11 @@ class Configuration implements StockConfigurationInterface
      */
     const XML_PATH_DISPLAY_PRODUCT_STOCK_STATUS = 'cataloginventory/options/display_product_stock_status';
 
+    /**
+     * Threshold qty config path
+     */
+    const XML_PATH_STOCK_THRESHOLD_QTY = 'cataloginventory/options/stock_threshold_qty';
+
     /**
      * @var ConfigInterface
      */
@@ -385,6 +390,19 @@ public function getDefaultConfigValue($field, $store = null)
         );
     }
 
+    /**
+     * @param null|string|bool|int|\Magento\Store\Model\Store $store
+     * @return string|null
+     */
+    public function getStockThresholdQty($store = null)
+    {
+        return $this->scopeConfig->getValue(
+            self::XML_PATH_STOCK_THRESHOLD_QTY,
+            \Magento\Store\Model\ScopeInterface::SCOPE_STORE,
+            $store
+        );
+    }
+
     /**
      * Retrieve inventory item options (used in config)
      *

app/code/Magento/CatalogInventory/Model/Indexer/Stock/AbstractAction.php

@@ -8,8 +8,7 @@
 
 namespace Magento\CatalogInventory\Model\Indexer\Stock;
 
-use Magento\Catalog\Model\Category;
-use Magento\Catalog\Model\Product;
+use Magento\Framework\App\ObjectManager;
 use Magento\Framework\App\ResourceConnection;
 
 /**
@@ -66,6 +65,11 @@ abstract class AbstractAction
      */
     private $eventManager;
 
+    /**
+     * @var CacheCleaner
+     */
+    private $cacheCleaner;
+
     /**
      * @param ResourceConnection $resource
      * @param \Magento\CatalogInventory\Model\ResourceModel\Indexer\StockFactory $indexerFactory
@@ -219,14 +223,31 @@ protected function _deleteOldRelations($tableName)
      * Refresh entities index
      *
      * @param array $productIds
-     * @return array Affected ids
+     * @return $this
      */
     protected function _reindexRows($productIds = [])
     {
-        $connection = $this->_getConnection();
         if (!is_array($productIds)) {
             $productIds = [$productIds];
         }
+
+        $this->getCacheCleaner()->clean($productIds, function () use ($productIds) {
+            $this->doReindex($productIds);
+        });
+
+        return $this;
+    }
+
+    /**
+     * Refresh entities index
+     *
+     * @param array $productIds
+     * @return void
+     */
+    private function doReindex($productIds = [])
+    {
+        $connection = $this->_getConnection();
+
         $parentIds = $this->getRelationsByChild($productIds);
         $processIds = $parentIds ? array_merge($parentIds, $productIds) : $productIds;
 
@@ -247,11 +268,17 @@ protected function _reindexRows($productIds = [])
                 $indexer->reindexEntity($byType[$indexer->getTypeId()]);
             }
         }
-        
-        $this->cacheContext->registerEntities(Product::CACHE_TAG, $productIds);
-        $this->eventManager->dispatch('clean_cache_by_tags', ['object' => $this->cacheContext]);
-        
-        return $this;
+    }
+
+    /**
+     * @return CacheCleaner
+     */
+    private function getCacheCleaner()
+    {
+        if (null === $this->cacheCleaner) {
+            $this->cacheCleaner = ObjectManager::getInstance()->get(CacheCleaner::class);
+        }
+        return $this->cacheCleaner;
     }
 
     /**

app/code/Magento/CatalogInventory/Model/Indexer/Stock/CacheCleaner.php

@@ -0,0 +1,136 @@
+<?php
+/**
+ * @category    Magento
+ * @package     Magento_CatalogInventory
+ * Copyright © 2016 Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+namespace Magento\CatalogInventory\Model\Indexer\Stock;
+
+use Magento\CatalogInventory\Api\StockConfigurationInterface;
+use Magento\Framework\App\ResourceConnection;
+use Magento\Framework\DB\Adapter\AdapterInterface;
+use Magento\Framework\Event\ManagerInterface;
+use Magento\Framework\Indexer\CacheContext;
+use Magento\CatalogInventory\Model\Stock;
+use Magento\Catalog\Model\Product;
+
+/**
+ * Clean product cache only when stock status was updated
+ */
+class CacheCleaner
+{
+    /**
+     * @var ResourceConnection
+     */
+    private $resource;
+
+    /**
+     * @var StockConfigurationInterface
+     */
+    private $stockConfiguration;
+
+    /**
+     * @var CacheContext
+     */
+    private $cacheContext;
+
+    /**
+     * @var ManagerInterface
+     */
+    private $eventManager;
+
+    /**
+     * @var AdapterInterface
+     */
+    private $connection;
+
+    /**
+     * @param ResourceConnection $resource
+     * @param StockConfigurationInterface $stockConfiguration
+     * @param CacheContext $cacheContext
+     * @param ManagerInterface $eventManager
+     */
+    public function __construct(
+        ResourceConnection $resource,
+        StockConfigurationInterface $stockConfiguration,
+        CacheContext $cacheContext,
+        ManagerInterface $eventManager
+    ) {
+        $this->resource = $resource;
+        $this->stockConfiguration = $stockConfiguration;
+        $this->cacheContext = $cacheContext;
+        $this->eventManager = $eventManager;
+    }
+
+    /**
+     * @param array $productIds
+     * @param callable $reindex
+     * @return void
+     */
+    public function clean(array $productIds, callable $reindex)
+    {
+        $productStatusesBefore = $this->getProductStockStatuses($productIds);
+        $reindex();
+        $productStatusesAfter = $this->getProductStockStatuses($productIds);
+        $productIds = $this->getProductIds($productStatusesBefore, $productStatusesAfter);
+        if ($productIds) {
+            $this->cacheContext->registerEntities(Product::CACHE_TAG, $productIds);
+            $this->eventManager->dispatch('clean_cache_by_tags', ['object' => $this->cacheContext]);
+        }
+    }
+
+    /**
+     * @param array $productIds
+     * @return array
+     */
+    private function getProductStockStatuses(array $productIds)
+    {
+        $select = $this->getConnection()->select()
+            ->from(
+                $this->resource->getTableName('cataloginventory_stock_status'),
+                ['product_id', 'stock_status', 'qty']
+            )->where('product_id IN (?)', $productIds)
+            ->where('stock_id = ?', Stock::DEFAULT_STOCK_ID)
+            ->where('website_id = ?', $this->stockConfiguration->getDefaultScopeId());
+
+        $statuses = [];
+        foreach ($this->getConnection()->fetchAll($select) as $item) {
+            $statuses[$item['product_id']] = $item;
+        }
+        return $statuses;
+    }
+
+    /**
+     * @param array $productStatusesBefore
+     * @param array $productStatusesAfter
+     * @return array
+     */
+    private function getProductIds(array $productStatusesBefore, array $productStatusesAfter)
+    {
+        $productIds = [];
+        $stockThresholdQty = $this->stockConfiguration->getStockThresholdQty();
+        foreach ($productStatusesBefore as $productId => $statusBefore) {
+            $statusAfter = $productStatusesAfter[$productId];
+            if ($statusBefore['stock_status'] !== $statusAfter['stock_status']
+                || ($stockThresholdQty && $statusAfter['qty'] <= $stockThresholdQty)) {
+                $productIds[] = $productId;
+            }
+        }
+
+        return $productIds;
+    }
+
+    /**
+     * @return AdapterInterface
+     */
+    private function getConnection()
+    {
+        if (null === $this->connection) {
+            $this->connection = $this->resource->getConnection();
+        }
+
+        return $this->connection;
+    }
+}