Google uses the MySQL open source relational database internally for some applications that aren't search related. And its engineers are keen to improve the code by making their improvements publicly available.

"We think MySQL is a fantastic data storage solution, and as our projects push the requirements for the database in certain areas, we've made changes to enhance MySQL itself, mainly in the areas of high availability and manageability," said Google engineer Mark Callaghan in a blog post.

MySQL is the second most popular database behind Microsoft SQL Server, according to a winter 2006 report from Evans Data. Oracle comes in second if you combine its database offerings. The situation is similar among wireless developers, almost 30% of who use Microsoft SQL Server compared to the 20% who use MySQL.

Callaghan said that while Google would like to see its changes become part of an official MySQL release, he and others wanted the public to have access to the modified code.

The new features include support for "for semi-synchronous replication, mirroring the binlog from a master to a slave, quickly promoting a slave to a master during failover, and keeping InnoDB and replication state on a slave consistent during crash recovery."

There are also new manageability features such as "new SQL statements for monitoring resource usage by table and account."

The patch works with version 4 and Google expects version 5 support shortly.