I also enjoyed the lecture on MySQL query tuning method that you recommended, and I found the lecture very informative. I will leave a few notes because I think it would be good for those who are interested in the lecture. 1. It contains the parts necessary for actual service operation. - This lecture really considers the initial model, from controlling external access to how to configure security. 2. The actual data provided is more helpful than expected. - It provides data that is very easy to test the concepts and methods provided by MySQL, and I think it is the best lecture for practicing development. I enjoyed the lecture. Thank you.