MC-31089: [Escalation] [SAQ] - Customer migration is too slow

Author: dhorytskyi

app/code/Magento/CustomerImportExport/Model/Import/Address.php

@@ -475,7 +475,7 @@ public function prepareCustomerData($rows): void
 
         $ids = [];
         foreach ($customersPresent as $customerData) {
-            $id = $this->getCustomerStorage()->getCustomerId(
+            $id = $this->getCustomerStorage()->getLoadedCustomerId(
                 $customerData['email'],
                 $customerData['website_id']
             );

app/code/Magento/CustomerImportExport/Model/ResourceModel/Import/Customer/Storage.php

@@ -9,8 +9,6 @@
 use Magento\Customer\Model\ResourceModel\Customer\CollectionFactory as CustomerCollectionFactory;
 use Magento\Framework\DataObject;
 use Magento\Framework\DB\Select;
-use Magento\ImportExport\Model\ResourceModel\CollectionByPagesIterator;
-use Magento\ImportExport\Model\ResourceModel\CollectionByPagesIteratorFactory;
 
 /**
  * Storage to check existing customers.
@@ -38,13 +36,6 @@ class Storage
      */
     protected $_pageSize;
 
-    /**
-     * Collection by pages iterator.
-     *
-     * @var CollectionByPagesIterator
-     */
-    protected $_byPagesIterator;
-
     /**
      * @var CustomerCollectionFactory
      */
@@ -71,21 +62,16 @@ class Storage
 
     /**
      * @param CustomerCollectionFactory $collectionFactory
-     * @param CollectionByPagesIteratorFactory $colIteratorFactory
      * @param array $data
      */
     public function __construct(
         CustomerCollectionFactory $collectionFactory,
-        CollectionByPagesIteratorFactory $colIteratorFactory,
         array $data = []
     ) {
         $this->_customerCollection = isset(
             $data['customer_collection']
         ) ? $data['customer_collection'] : $collectionFactory->create();
-        $this->_pageSize = isset($data['page_size']) ? $data['page_size'] : 0;
-        $this->_byPagesIterator = isset(
-            $data['collection_by_pages_iterator']
-        ) ? $data['collection_by_pages_iterator'] : $colIteratorFactory->create();
+        $this->_pageSize = isset($data['page_size']) ? (int) $data['page_size'] : 0;
         $this->customerCollectionFactory = $collectionFactory;
     }
 
@@ -95,21 +81,20 @@ public function __construct(
      * @param array $customerIdentifiers With keys "email" and "website_id".
      * @return void
      */
-    private function loadCustomersData(array $customerIdentifiers)
+    private function loadCustomersData(array $customerIdentifiers): void
     {
-        $this->_pageSize;
-
         /** @var CustomerCollection $collection */
         $collection = $this->customerCollectionFactory->create();
         $collection->removeAttributeToSelect();
         $select = $collection->getSelect();
         $customerTableId = array_keys($select->getPart(Select::FROM))[0];
 
-        $getChuck = function (int $offset) use ($customerIdentifiers) {
-            return array_slice($customerIdentifiers, $offset, $this->_pageSize);
+        $pageSize = $this->_pageSize ?: count($customerIdentifiers);
+        $getChuck = function (int $offset) use ($customerIdentifiers, $pageSize) {
+            return array_slice($customerIdentifiers, $offset, $pageSize);
         };
         $offset = 0;
-        for ($chunk = $getChuck($offset); !empty($chunk); $offset += $this->_pageSize, $chunk = $getChuck($offset)) {
+        for ($chunk = $getChuck($offset); !empty($chunk); $offset += $pageSize, $chunk = $getChuck($offset)) {
             $emails = array_column($chunk, 'email');
             $chunkSelect = clone $select;
             $chunkSelect->where($customerTableId . '.email IN (?)', $emails);