I've quit the company now, but... When I actually ran the first-come-first-served 100 coupon event, the DB died... Whenever someone tried to issue a coupon and order, it took 5 seconds to load the page... I remember the chaos.. In the end, I had to deal with it by increasing the temporary ec2 instance and the db server, but if I had seen this lecture before, I would have suggested it and reflected it myself.. I could have had a good experience.. Now that I'm trying to test it myself.. The server cost is not cheap, and I'm very sorry.. I hope this lecture spreads widely so that people like me won't have regrets... I listened to the lecture well. Thanks to you, I became interested in Redis and Kafka, and I want to study more. Thank you.