I used to work at Google long ago in the platforms division, in fact I worked on the BigTable cache (among other things, mostly related to performance). It would be very sad indeed if today's SRE book dismisses caching as a vital and standard optimization strategy and instead plays all kinds of gotchas with potential candidates as I believe you're doing.

With that said, you article you linked does not in any way support your claim about caching, on the contrary it hardly discusses caching at all. It's as if you just wanted to dump a document you thought I wouldn't read as a way to be dismissive.

And yeah this is exactly my point. If you present a "standard and common" solution that isn't applicable to the question I actually asked, and if you blindly apply solutions without thinking about what problem is actually being solved, then that's bad in an interview.

Average latency is usually not the thing you want to reduce because it's not representative of what any actual user is experiencing.

With that said, to the best of my knowledge it is the same as my HackerNews handle, so you are welcome to find whatever info you'd like on that, but please understand your request is very creepy and akward.

In fact, one of the key projects that is being worked on is to improve caching to reduce latency both at median and at tail.