One of the core product features of bitly has always been metrics. Unlike tools like google analytics, bitly metrics have always been a way to gather website metrics when you don’t control the website. Want metrics for a book you wrote on Amazon? Use a bitly link. Want metrics for a blog post? You can use a bitly link for that, too. As bitly usage has grown, one of the systems that has evolved several times along the way is our metrics platform. Originally implemented as log files with a hierarchical timestamp key, later metrics data was loaded into a flat mysql table. A subsequent revision moved that data into a cluster of tokyocabinet servers. That was eventually supplemented with some additional metrics datasets in mongodb. By early 2011 we were using 3 different metrics systems, and had outgrown 3 others. We started with a set of goals to build a scalable time series database application, which we now call Clickatron.