iterate-huge-magento2-result.php

<?php

use Magento\Framework\App\ResourceConnection;
use Magento\Framework\Model\ResourceModel\IteratorFactory;

class HugeTableIterator
{
    /** @var ResourceConnection */
    private $resourceConnection;
    
    /** @var IteratorFactory */
    private $iteratorFactory;

    public function __construct(ResourceConnection $resourceConnection, IteratorFactory $iteratorFactory)
    {
        $this->resourceConnection = $resourceConnection;
        $this->iteratorFactory = $iteratorFactory;
    }
    
    public function processResults(): void
    {
        $connection = $this->resourceConnection->getConnection();
        $iterator = $this->iteratorFactory->create();
        
        $query = $connection->select()->from('huge_table');

        $iterator->walk((string) $query, [function (array $result) {
            // do something with $result
        }], [], $connection);
    }
}