Piwik only works on Mysql, where all the development and testing is done. Supporting multiple databases is a long term objective for Piwik, but not our current focus. This project will require a lot of testing, coding… and human talent. We call on the community to help us in bringing better technology support to Piwik!
Postgresql: There is a beta non official posgresql port built by a community member, more information about Postgresql Piwik on this ticket. We welcome constructive discussions and pull requests in this area. Please test the fork and report any feedback you have. We want ultimately to merge this fork back in Piwik core.
SQLite: similarly to Postgresql we would love to support SQLite, especially for low traffic websites. Piwik should ideally run anywhere, even on cheap and very small servers, Freedom boxes and USB sticks (in your pocket?). We would like to work with you to support SQLite if you can contribute in some way.
MariaDB: Piwik is already fully compatible with MariaDB and other Mysql compatible databases. Feel free to use them with Piwik!
TokuDB: You can use Piwik with TokuDB which may help if you manage a high traffic Piwik service. Learn more in the TokuDB FAQ
Nosql: Regarding using Piwik with Nosql databases, we are also considering and listening to user feedback. Our current understanding is that Nosql would have to be implemented in a hybrid way, where Nosql would be used for visitor logs and events, but not for websites, users, reports, and other features. Using Mongodb, Hadoop, this would not remove Mysql, but it would maybe allow to scale further.
Column storage databases: As well as Nosql, and possibly a better approach are the ‘Column storage databases’. This is a technology especially tailored to analytics workload. Some solutions are GPL such as Infinidb are partly compatible with Mysql queries. This could also offer a superb solution to scaling Piwik further.
Summary: Get in touch with the Piwik team if you are interested in working with us in this area. Piwik is an open platform, our long term vision is that Piwik will ultimately run anywhere, or when configured right, that it will handle billions of requests. Stay tuned, let’s hack it.