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<?php
/**
* Matomo - free/libre analytics platform
*
* @link https://matomo.org
* @license https://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
*/
namespace Piwik\Db;
use Piwik\Db;
use Piwik\Option;
class TransactionLevel
{
public const TEST_OPTION_NAME = 'TransactionLevel.testOption';
private $statusBackup;
/**
* @var TransactionalDatabaseInterface $transactionalDatabase
*/
private $transactionalDatabase;
public function __construct(TransactionalDatabaseInterface $transactionalDatabase)
{
$this->transactionalDatabase = $transactionalDatabase;
}
public function canLikelySetTransactionLevel()
{
$dbSettings = new Db\Settings();
return strtolower($dbSettings->getEngine()) === 'innodb';
}
/**
* @deprecated Use `setTransactionLevelForNonLockingReads`
*/
public function setUncommitted()
{
return $this->setTransactionLevelForNonLockingReads();
}
public function setTransactionLevelForNonLockingReads(): bool
{
if ($this->transactionalDatabase->getSupportsTransactionLevelForNonLockingReads() === false) {
// we know "Uncommitted" transaction level is not supported, we don't need to do anything as it won't work to set the status
return false;
}
try {
$backup = $this->transactionalDatabase->getCurrentTransactionIsolationLevelForSession();
} catch (\Exception $e) {
$this->transactionalDatabase->setSupportsTransactionLevelForNonLockingReads(false);
return false;
}
try {
$this->transactionalDatabase->setTransactionIsolationLevel(Schema::getInstance()->getSupportedReadIsolationTransactionLevel());
$this->statusBackup = $backup;
if ($this->transactionalDatabase->getSupportsTransactionLevelForNonLockingReads() === null) {
// the first time we need to check if the transaction level actually works by
// trying to set something w/ the new transaction isolation level
Option::set(self::TEST_OPTION_NAME, '1');
}
$this->transactionalDatabase->setSupportsTransactionLevelForNonLockingReads(true);
} catch (\Exception $e) {
// setting the transaction level status did not work
// catch eg 1665 Cannot execute statement: impossible to write to binary log since BINLOG_FORMAT = STATEMENT and at least one table uses a storage engine limited to row-based logging. InnoDB is limited to row-logging when transaction isolation level is READ COMMITTED or READ UNCOMMITTED
$this->transactionalDatabase->setSupportsTransactionLevelForNonLockingReads(false);
$this->restorePreviousStatus();
return false;
}
return true;
}
public function restorePreviousStatus()
{
if ($this->statusBackup) {
$value = strtoupper($this->statusBackup);
$this->statusBackup = null;
$value = str_replace('-', ' ', $value);
if (in_array($value, array('REPEATABLE READ', 'READ COMMITTED', 'SERIALIZABLE'))) {
$this->transactionalDatabase->setTransactionIsolationLevel($value);
} elseif ($value !== 'READ UNCOMMITTED') {
$this->transactionalDatabase->setTransactionIsolationLevel('REPEATABLE READ');
}
}
}
}
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