As one of the largest users of MySQL, Twitter uses the database software to store most of the data its 140 million users generate.

"Due to our scale, we push MySQL a lot further than most companies," wrote Twitter engineers Jeremy Cole and Davi Arnau, in a blog post

This code addresses a crucial issue for MySQL: the ability to scale to meet the demands of large data-processing-intensive systems, such as Twitter's. Much of the appeal behind NoSQL-styled databases, such as Cassandra, has come from how they bypass the limits that relational databases systems such as MySQL have had in scaling across multiple servers.

Among the changes is some code that would allow MySQL to run more effectively on large pooled-memory systems. Specifically, it allocates during startup all the memory needed for the core InnoDB database engine. It also ensures adequate performance even when available server memory is at a minimum.