Reverting 36155

Author: engcom-Charlie

app/code/Magento/Eav/Model/Mview/ChangeLogBatchWalker.php

@@ -0,0 +1,120 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+namespace Magento\Eav\Model\Mview;
+
+use Magento\Framework\App\ResourceConnection;
+use Magento\Framework\DB\Sql\Expression;
+use Magento\Framework\Mview\View\ChangeLogBatchWalkerInterface;
+use Magento\Framework\Mview\View\ChangelogInterface;
+
+/**
+ * Class BatchIterator
+ */
+class ChangeLogBatchWalker implements ChangeLogBatchWalkerInterface
+{
+    private const GROUP_CONCAT_MAX_VARIABLE = 'group_concat_max_len';
+    /** ID is defined as small int. Default size of it is 5 */
+    private const DEFAULT_ID_SIZE = 5;
+
+    /**
+     * @var ResourceConnection
+     */
+    private $resourceConnection;
+
+    /**
+     * @var array
+     */
+    private $entityTypeCodes;
+
+    /**
+     * @param ResourceConnection $resourceConnection
+     * @param array $entityTypeCodes
+     */
+    public function __construct(
+        ResourceConnection $resourceConnection,
+        array $entityTypeCodes = []
+    ) {
+        $this->resourceConnection = $resourceConnection;
+        $this->entityTypeCodes = $entityTypeCodes;
+    }
+
+    /**
+     * Calculate EAV attributes size
+     *
+     * @param ChangelogInterface $changelog
+     * @return int
+     * @throws \Exception
+     */
+    private function calculateEavAttributeSize(ChangelogInterface $changelog): int
+    {
+        $connection = $this->resourceConnection->getConnection();
+
+        if (!isset($this->entityTypeCodes[$changelog->getViewId()])) {
+            throw new \Exception('Entity type for view was not defined');
+        }
+
+        $select = $connection->select();
+        $select->from(
+            $this->resourceConnection->getTableName('eav_attribute'),
+            new Expression('COUNT(*)')
+        )
+            ->joinInner(
+                ['type' => $connection->getTableName('eav_entity_type')],
+                'type.entity_type_id=eav_attribute.entity_type_id'
+            )
+            ->where('type.entity_type_code = ?', $this->entityTypeCodes[$changelog->getViewId()]);
+
+        return (int) $connection->fetchOne($select);
+    }
+
+    /**
+     * Prepare group max concat
+     *
+     * @param int $numberOfAttributes
+     * @return void
+     * @throws \Exception
+     */
+    private function setGroupConcatMax(int $numberOfAttributes): void
+    {
+        $connection = $this->resourceConnection->getConnection();
+        $connection->query(sprintf(
+            'SET SESSION %s=%s',
+            self::GROUP_CONCAT_MAX_VARIABLE,
+            $numberOfAttributes * (self::DEFAULT_ID_SIZE + 1)
+        ));
+    }
+
+    /**
+     * @inheritdoc
+     * @throws \Exception
+     */
+    public function walk(ChangelogInterface $changelog, int $fromVersionId, int $toVersion, int $batchSize)
+    {
+        $connection = $this->resourceConnection->getConnection();
+        $numberOfAttributes = $this->calculateEavAttributeSize($changelog);
+        $this->setGroupConcatMax($numberOfAttributes);
+        $select = $connection->select()->distinct(true)
+            ->where(
+                'version_id > ?',
+                (int) $fromVersionId
+            )
+            ->where(
+                'version_id <= ?',
+                $toVersion
+            )
+            ->group([$changelog->getColumnName(), 'store_id'])
+            ->limit($batchSize);
+
+        $columns = [
+            $changelog->getColumnName(),
+            'attribute_ids' => new Expression('GROUP_CONCAT(attribute_id)'),
+            'store_id'
+        ];
+        $select->from($changelog->getName(), $columns);
+        return $connection->fetchAll($select);
+    }
+}