LargeQueryTest.php

<?php

namespace Drupal\KernelTests\Core\Database;

use Drupal\Component\Utility\Environment;
use Drupal\Core\Database\Database;
use Drupal\Core\Database\DatabaseException;

/**
 * Tests handling of large queries.
 *
 * @group Database
 */
class LargeQueryTest extends DatabaseTestBase {
    
    /**
     * Tests truncation of messages when max_allowed_packet exception occurs.
     */
    public function testMaxAllowedPacketQueryTruncating() {
        // Only run this test for the 'mysql' driver.
        $driver = $this->connection
            ->driver();
        if ($driver !== 'mysql') {
            $this->markTestSkipped("MySql tests can not run for driver '{$driver}'.");
        }
        // The max_allowed_packet value is configured per database instance.
        // Retrieve the max_allowed_packet value from the current instance and
        // check if PHP is configured with sufficient allowed memory to be able
        // to generate a query larger than max_allowed_packet.
        $max_allowed_packet = $this->connection
            ->query('SELECT @@global.max_allowed_packet')
            ->fetchField();
        if (!Environment::checkMemoryLimit($max_allowed_packet + 16 * 1024 * 1024)) {
            $this->markTestSkipped('The configured max_allowed_packet exceeds the php memory limit. Therefore the test is skipped.');
        }
        $long_name = str_repeat('a', $max_allowed_packet + 1);
        try {
            $this->connection
                ->query('SELECT name FROM {test} WHERE name = :name', [
                ':name' => $long_name,
            ]);
            $this->fail("An exception should be thrown for queries larger than 'max_allowed_packet'");
        } catch (DatabaseException $e) {
            // Close and re-open the connection. Otherwise we will run into error
            // 2006 "MySQL server had gone away" afterwards.
            Database::closeConnection();
            Database::getConnection();
            // Got a packet bigger than 'max_allowed_packet' bytes exception thrown.
            $this->assertEquals(1153, $e->getPrevious()->errorInfo[1]);
            // 'max_allowed_packet' exception message truncated.
            // Use strlen() to count the bytes exactly, not the unicode chars.
            $this->assertLessThanOrEqual($max_allowed_packet, strlen($e->getMessage()));
        }
    }

}