ACPT-677: Catalog product grid improvement

Author: adifucan

app/code/Magento/Backend/etc/adminhtml/system.xml

@@ -480,6 +480,15 @@
                     <source_model>Magento\Config\Model\Config\Source\Yesno</source_model>
                 </field>
             </group>
+            <group id="grid" translate="label" type="text" sortOrder="45" showInDefault="1">
+                <label>Admin Grids</label>
+                <field id="show_approximate_total_number_of_products" translate="label comment"
+                       type="select" sortOrder="1" showInDefault="1" canRestore="1">
+                    <label>Show approximate total number of products</label>
+                    <source_model>Magento\Config\Model\Config\Source\Yesno</source_model>
+                    <comment>Show approximate total number of products in products grid header.</comment>
+                </field>
+            </group>
         </section>
         <section id="web" translate="label" type="text" sortOrder="20" showInDefault="1" showInWebsite="1" showInStore="1">
             <label>Web</label>

app/code/Magento/Backend/etc/config.xml

@@ -31,6 +31,11 @@
                 <max_height>1200</max_height>
             </upload_configuration>
         </system>
+        <admin>
+            <grid>
+                <show_approximate_total_number_of_products>1</show_approximate_total_number_of_products>
+            </grid>
+        </admin>
         <general>
             <validator_data>
                 <input_types>

app/code/Magento/Catalog/Ui/DataProvider/Product/ProductCollection.php

@@ -5,6 +5,8 @@
  */
 namespace Magento\Catalog\Ui\DataProvider\Product;
 
+use Magento\Framework\DB\Select;
+
 /**
  * Collection which is used for rendering product list in the backend.
  *
@@ -25,4 +27,56 @@ protected function _productLimitationJoinPrice()
         $this->_productLimitationFilters->setUsePriceIndex(false);
         return $this->_productLimitationPrice(true);
     }
+
+    /**
+     * @inheritdoc
+     */
+    public function getSize()
+    {
+        if ($this->_scopeConfig->getValue('admin/grid/show_approximate_total_number_of_products')) {
+            $sql = $this->getSelectCountSql();
+            return $this->analyzeCount($sql);
+        }
+
+        return parent::getSize();
+    }
+
+    /**
+     * Analyze amount of entities in DB.
+     *
+     * @param $sql
+     * @return int|mixed
+     * @throws \Zend_Db_Select_Exception
+     * @throws \Zend_Db_Statement_Exception
+     */
+    private function analyzeCount($sql)
+    {
+        $results = $this->getConnection()->query('EXPLAIN ' . $sql)->fetchAll();
+        $alias = $this->getMainTableAlias();
+
+        foreach ($results as $result) {
+            if ($result['table'] == $alias) {
+                return $result['rows'];
+            }
+        }
+
+        return 0;
+    }
+
+    /**
+     * Identify main table alias or its name if alias is not defined.
+     *
+     * @return string
+     * @throws \LogicException
+     * @throws \Zend_Db_Select_Exception
+     */
+    private function getMainTableAlias()
+    {
+        foreach ($this->getSelect()->getPart(Select::FROM) as $tableAlias => $tableMetadata) {
+            if ($tableMetadata['joinType'] == 'from') {
+                return $tableAlias;
+            }
+        }
+        throw new \LogicException("Main table cannot be identified.");
+    }
 }

app/code/Magento/Sales/etc/adminhtml/di.xml

@@ -52,4 +52,9 @@
     <type name="Magento\Framework\View\Element\UiComponent\DataProvider\SearchResult">
         <plugin name="orderGridCollectionFilterPlugin" type="Magento\Sales\Plugin\Model\ResourceModel\Order\OrderGridCollectionFilter"/>
     </type>
+    <type name="Magento\Sales\Block\Adminhtml\Order\Create\Search\Grid\DataProvider\ProductCollection">
+        <arguments>
+            <argument name="collectionFactory" xsi:type="object">\Magento\Catalog\Ui\DataProvider\Product\ProductCollectionFactory</argument>
+        </arguments>
+    </type>
 </config>