How do I throttle my site's API users?

Question

The legitimate users of my site occasionally hammer the server with API requests that cause undesirable results. I want to institute a limit of no more than say one API call

Answer 1

I don't know if this thread is still alive or not but I would suggest to keep these statistics in memory cache like memcached. This will reduce the overhead of logging the request to the DB but still serve the purpose.