RisingLight is an educational database system built in Rust. Recently, we have rewritten its query engine and SQL optimizer using egg. We have implemented classic database optimization techniques, including both rule-based and cost-based optimization. Thanks to the flexibility and expressive power of egg, our new optimizer, developed with just over a thousand lines of code, can effectively optimize real-world TPC-H queries within tens of milliseconds. In this talk, we will share our experiences from a user’s perspective on how we utilized egg to construct the database optimizer, our approaches to solving practical problems, and areas where egg could be further improved.