Will mysql Insert slow page down if its used on every request? PHP

Will mysql Insert slow page down if its used on every request? PHP

I have a MVC framework that has a Request class which handles all
requests. I log each request that comes in the database and the columns
for the request log table is as follows:
ID (auto-increment)
Controller
Action
Params (GET, POST, PUT, DELETE)
Params (MVC params delimited by slash "/")
Request Method (GET, POST, PUT, DELETE)
Request Type (HTML, JSON, XML)
Is Request Ajax (true/false)
Referer URL
Request URI
Browser (User Agent Browser)
Browser Version
IP
Platform
Request Time (datetime)
Now that I think about it, if I have 100+ users online, each one making
around 500+ requests a day I get 100*500 = 50,000 rows per day and per
year it comes out around 18 Million.
Now after 1-2 years if I dont clear the log, will it be slower for users
to insert their request into the table?
Is it bad idea to log every request?
Reason: the reason i want to log every request is to detect kind of DDOS
attack so that if there are more than 10 requests per 30 seconds lock
account for 20 minutes.