Re:We don’t use a staging environment
by alasdair_ on Sunday April 03, 2022 @08:48PM
(#30902313)
I worked on ad systems at Facebook, and yes it's (approximately) true for those as well.
The thing to realize that "in production" almost never means "rolled out to 100% of users from 0%". Instead you'd do very slow rollouts to, say, 1% of people in Hungary (or whatever) and use a ton of automatic measurements over time as well as lots and lots of tests to validate that things were working as expected before rolling out a little more, then a little more after that. By the time the code is actually being hit by the majority of users, it's often been run billions of times already.
The thing to realize that "in production" almost never means "rolled out to 100% of users from 0%". Instead you'd do very slow rollouts to, say, 1% of people in Hungary (or whatever) and use a ton of automatic measurements over time as well as lots and lots of tests to validate that things were working as expected before rolling out a little more, then a little more after that. By the time the code is actually being hit by the majority of users, it's often been run billions of times already.