PDO MySQL Emulation of Prepared Statements: Enable or Disable?

PDO MySQL: Emulation of Prepared Statements: To Enable or Disable

Concerns have been raised regarding the use of PDO::ATTR_EMULATE_PREPARES. Let's delve into the topic and weigh the advantages and disadvantages to determine whether to enable or disable emulation.

Claims and Concerns

Statements have been made about PDO's prepared statement emulation:

• Performance improvement with emulation due to MySQL's native prepare bypassing the query cache.
• Enhanced security with native prepare for preventing SQL injection.
• Better error reporting with native prepare.

Clarifying the Facts

• Security: Emulation has no impact on security. Escaping of parameters occurs regardless, whether in PDO or on the MySQL server.
• Performance: Prepared statements can use the query cache in MySQL versions 5.1.17 and later.
• Error Reporting: Syntax errors may be detected at prepare time with native prepares, while emulation defers syntax checking to execution time.

Additional Considerations

• Native prepared statements incur a higher preparation cost, potentially slowing down execution for single-use statements.
• Native prepares may offer query plan caching optimizations, but this is not confirmed in MySQL.
• Emulation allows the separation of syntax and execution concerns.

Recommendation

Based on these considerations, for MySQL 5.1.17 and below, it is advisable to emulate prepared statements. For newer versions of MySQL, it is recommended to disable emulation for optimal performance and error reporting.

Sample PDO Connection Function

To simplify the configuration of PDO settings, consider using a connection function like the one below:

function connect_PDO($settings) {
    $dbh = new PDO(...);
    $dbh->setAttribute(PDO::ATTR_EMULATE_PREPARES, version_compare($dbh->getAttribute(PDO::ATTR_SERVER_VERSION), '5.1.17', '<'));
    return $dbh;
}

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