I've been using a combination of MySQL and Cassandra for about a year now on a project that now serves about 20k users. We use Cassandra for storing large entities and MySQL to store meta data that allows us to do better ad hoc querying. It's worked quite well for us. During this time we have also been able to migrate some of our tables in MySQL to Cassandra if MySQL performance / capacity became a problem. This may seem obvious but if you're planning on creating a data model that spans multiple databases make sure you encapsulate the logic to read/write/delete information in a good data model library and only use that library to access your data. This is good practice anyway but when you add the extra complication of multiple databases that may reference one another it's an absolute must.

On Sun, Feb 26, 2012 at 8:06 AM, R. Verlangen <robin@us2.nl> wrote:
Hi there,

I'm currently busy with the technical design of a new project. Of course it will depend on your needs, but is it weird to combine Cassandra with a SQL language like MySQL?

In my usecase it would be nice because we have some tables/CF's with lots and lots of data that does not really have to be consistent 100%, but also have some data that should be always consistent.

What do you think of this?

With kind regards,
Robin Verlangen