NamePros: Obscure Nginx FastCGI bug uncovered in the aftermath of Duck.com move

Duck.com domain name transfer hammered NamePros servers so hard that it singlehandedly uncovered a fairly obscure bug in Nginx's FastCGI caching. It's gone unnoticed for years, including during rigorous load testing.

Preliminary evidence suggests that fastcgi_cache_key doesn't handle $cookie_* variables correctly. If the cookie doesn't exist, it seems to result in a unique key every time. (The workaround was to assign the $cookie_* variable to another variable and then use that in fastcgi_cache_key.)

If anyone is curious what sort of increase in traffic you should expect from a link to your site appearing on HN, NamePros is getting about 230 additional backend requests per second--that doesn't include anything cached by Cloudflare.

Live Monitor: https://www.nameprosstatus.com

source: https://news.ycombinator.com/item?id=18665292

I appreciate the interest, but this is definitely premature. I still haven't been able to reproduce it in controlled tests. As I said in the thread to which you linked, I'll follow up once I've fully investigated.