The future direction of the development of the PHP PDO, and PDO-MySQLND extensions is gaining momentum as a flurry of activity from developers, most significantly from the SUN/MySQL development camp.
From its first inception, the PDO driver was deemed a addition to the PHP toolkit by providing a standard interface to databases, but little development on PDO has occurred since that time. A new new push to further the development has seen SUN/MySQL lead the way in developing the missing test suite for the PDO driver. Since the purchase of MySQL, SUN has been an eager player in the development of PDO-MySQL and has now moved into the development of mysqlnd.
The push from SUN/MySQL to further PDO development is a sign of the larger number of developers within the PHP community who are currently seeking to further all RDBMS extensions. The challenge comes from the attempt to further unify the drivers as each PDO extension behaves a little differently.
Suggestions that the development direction should adopt a more JDBC type approach, where the driver plus core approach would be abandoned, and thus provide greater flexibility in the development.
The superior memory management of the mysqlnd driver has long been known and is approximately forty percent faster as it omits a copy of data to memory. However, this has not successfully been ported to PDO and has not been adopted by other database drivers.
The test suite from SUN/MySQL is available now and shows the future direction from the SUN/MySQL camp.
Meanwhile, in the PDO 1 camp, an rfc has been released seeking further direction of the current PDO driver.