PDO::ATTR_EMULATE_PREPARES in MySQL: To Emulate or Not to Emulate?

PDO MySQL: The Quandary of PDO::ATTR_EMULATE_PREPARES

PDO::ATTR_EMULATE_PREPARES is a critical MySQL attribute that affects both performance and security. Understanding its nuances is crucial for informed decision-making.

Performance and Query Cache

It was once believed that enabling emulation boosted performance due to MySQL's native prepared statement bypassing the query cache. However, MySQL 5.1.17 (and later versions) allows prepared statements to leverage the query cache, effectively eliminating this performance disparity.

Security

Native prepares provide no additional security benefits compared to emulation. Both methods effectively escape query parameters, ensuring protection against SQL injection vulnerabilities.

Error Reporting

Disabling emulation may trigger syntax errors at prepare time, while emulation alerts users during execution. This distinction can impact error handling and debugging processes.

Additional Considerations

There is a slight performance overhead associated with native prepares due to their fixed preparation cost. If prepared statement objects are not reused, emulation may prove more efficient.

Recommendation

Based on the latest MySQL and PHP versions you cited, it is advisable to disable PDO::ATTR_EMULATE_PREPARES. This will ensure optimal error reporting and leverage query cache benefits when possible.

To streamline your setup, consider using a connection function like the one provided below, which sets the recommended attributes:

function connect_PDO($settings) {
  $dbh = new PDO($dsn, $settings['user'], $settings['pass'], $options);
  $serverversion = $dbh->getAttribute(PDO::ATTR_SERVER_VERSION);
  $emulate_prepares = (version_compare($serverversion, '5.1.17', '<'));
  $dbh->setAttribute(PDO::ATTR_EMULATE_PREPARES, $emulate_prepares);
  return $dbh;
}

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