I think this is a very good lecture to study Oracle DB from an engineer's perspective. It was easy to understand because it explained the structure of the instance and the part where the wait event occurs in a systematic and sequential manner. It took a long time, but it was tough. However, there was a warning sound every now and then, haha. It was inevitable, so I'll pass...ㅋ Since you can take the lecture unlimitedly, I think I'll keep looking for it and watching it again. Thank you!!! :)