The mysqli, PDO_MySQL and mysql PHP extensions are lightweight wrappers on top of a C client library. The extensions can either use the mysqlnd library or the libmysqlclient library. Choosing a library is a compile time decision.
The mysqlnd library is part of the PHP distribution since 5.3.0. It offers features like lazy connections and query caching, features that are not available with libmysqlclient, so using the built-in mysqlnd library is highly recommended. See the mysqlnd documentation for additional details, and a listing of features and functionality that it offers.
Example #1 Configure commands for using mysqlnd or libmysqlclient
// Recommended, compiles with mysqlnd $ ./configure --with-mysqli=mysqlnd --with-pdo-mysql=mysqlnd --with-mysql=mysqlnd // Alternatively recommended, compiles with mysqlnd as of PHP 5.4 $ ./configure --with-mysqli --with-pdo-mysql --with-mysql // Not recommended, compiles with libmysqlclient $ ./configure --with-mysqli=/path/to/mysql_config --with-pdo-mysql=/path/to/mysql_config --with-mysql=/path/to/mysql_config
Library feature comparison
It is recommended to use the mysqlnd library instead of the MySQL Client Server library (libmysqlclient). Both libraries are supported and constantly being improved.
| MySQL native driver (mysqlnd) | MySQL client server library (libmysqlclient) | |
|---|---|---|
| Part of the PHP distribution | Yes | No |
| PHP version introduced | 5.3.0 | N/A |
| License | PHP License 3.01 | Dual-License |
| Development status | Active | Active |
| Lifecycle | No end announced | No end announced |
| PHP 5.4 and above; compile default (for all MySQL extensions) | Yes | No |
| PHP 5.3; compile default (for all MySQL extensions) | No | Yes |
| Compression protocol support | Yes (5.3.1+) | Yes |
| SSL support | Yes (5.3.3+) | Yes |
| Named pipe support | Yes (5.3.4+) | Yes |
| Non-blocking, asynchronous queries | Yes | No |
| Performance statistics | Yes | No |
| LOAD LOCAL INFILE respects the open_basedir directive | Yes | No |
| Uses PHP's native memory management system (e.g., follows PHP memory limits) | Yes | No |
| Return numeric column as double (COM_QUERY) | Yes | No |
| Return numeric column as string (COM_QUERY) | Yes | Yes |
| Plugin API | Yes | Limited |
| Read/Write splitting for MySQL Replication | Yes, with plugin | No |
| Load Balancing | Yes, with plugin | No |
| Fail over | Yes, with plugin | No |
| Lazy connections | Yes, with plugin | No |
| Query caching | Yes, with plugin | No |
| Transparent query manipulations (E.g., auto-EXPLAIN or monitoring) | Yes, with plugin | No |
| Automatic reconnect | No | Optional |