Question: If I am using Zend\_Db classes to abstract my queries from the backend database, does it make a difference which mysql driver I use, pdo\_mysql vs. mysqli? My understanding of pdo\_mysql is it is also to provide abstraction, so I'm assuming that if I am using Zend\_Db, then I would not be taking advantage of the extra features as part of mysqli anyway. However, is one faster than the other from a performance perspective?

Answer: 
`Zend_Db`, generally speaking, is based on PDO and its various adapters, like `pdo_mysql`.

The mysqli adapter has been developped only for those who are using servers / hosts that doesn't come with PDO.

I don't think there is much of a difference between pdo\_mysql and mysqli, speaking of performance ; never heard of any -- so even if there is one, it shouldn't be that big.

The question I'd ask is : which adapters **can** you use in your application ?

Considering both `pdo_mysql` and `mysqli` allow to connect to a MySQL database, changing from one to the other should be quite easy : one line to change in your application's config.ini file ; and everything should keep working...

Personnaly, I'd probably go with the PDO adapter -- and switch to mysqli only if necessary, depending on the availability of PDO on my server.

But that's more because I generally use PDO than for any other "good" reason ^^
I've not used the Zend\_DB classes, but in my own (very non-rigourous) tests I've found PDO to be substantially faster than MySQLi.

<http://www.robpoyntz.com/blog/?p=260>