MySQL

MySQL is a database server that embodies an ingenious software architecture that maximizes speed and customizability. MySQL is unmatched in speed, compactness, stability and ease of deployment. The unique separation of the core server from the table handler makes it possible to run MySQL under strict transaction control or with ultrafast transactionless disk access, whichever is most appropriate for the situation.

Today MySQL is the most popular open source database server in the world with more than 2 million installations powering websites, data warehouses, business applications, logging systems and more. Customers such as Yahoo! Finance, MP3.com, Motorola, NASA, Silicon Graphics, and Texas Instruments use the MySQL server in mission-critical applications.

We have been working on MySQL and optimized operations for blazing fast performance. We have handled millions of records resulting in GBs of data size on MySQL along with PHP.

Checkout http://www.mysql.com for more information.