[pmahoney]

Many years ago (2011 or so?), I worked on a Rails app that used JRuby. The driving force was a small part of the app needing a Java library. I think we did see some performance benefit, or at least benefit from using multi-threaded web servers instead of process-per-request servers (like Unicorn).

However, we also ran into many problems that felt like we were the first to encounter them (few or no similar reports on project bug lists or StackOverflow etc.) which is never fun if you're under any kind of pressure to deliver.

In hindsight, if I had something small and reasonably isolated (a microservice?), it could make sense to use JRuby or Truffle (if you need some JVM lib; if it's purely for performance reasons I'd just grab a different language for that microservice). But for a larger app that pays the bills, I'd stick with the well-trod path (at the time that was MRI, Unicorn, single-threaded).

[headius]

Glad to hear you got some benefit from JRuby! A lot has changed since 2011, including much better compatibility and many little performance improvements. I'm not sure we were even on the current JRuby runtime (register-based IR + JVM JIT) at that time, which has improved perf and compat tremendously.

If you ever have any issues with JRuby again, please let us know. We spend most of our time supporting users and want them to have a good experience.