[simonw]

Do you mean this one? https://github.com/mysql/mysql-proxy

It let you do all sorts of clever tricks with Lua scripting, though oddly enough it looks like the repo was archived back in 2024 (and the last commit to it was 11 years ago), and the linked docs on https://dev.mysql.com/doc/mysql-proxy/en/ are a 404 now.

[kgeist]

MySQL also has https://github.com/vitessio/vitess which is alive and well.