The recent proliferation of multiple ‘Source Available’ and ‘open source-compatible’ licenses for previously open source databases has led to some hefty problems. If you don’t spend time researching and understanding the fine print of these licenses, then you can end up with all the features of a project that you want, along with a new one: lock-in.
One of the strengths of open source is the relatively small number of licences. GPL, BSD, MIT and Apache are well understood and account for over 90 per cent of released software.
At Percona, we’ve been discussing how ‘Not Open Source, Source Available’ licensing could be more widely understood. One example is the Polyform project. This is a group of licensing lawyers and technologists that have developed a set of standardised licenses for making source code available in different, easyto-understand ways, much like Creative Commons. Some may feel this legitimises those licenses to the detriment of open source. However, as long as we are clear on what open source is – and equally, when things are not open – this approach should help, not hinder.