This paper is from a conference a few months ago (SOSP), it's possible you read a pre-print (or maybe the CacheLib paper [1]).
Facebook publishes lots of systems research! FWIW I also write a fair bit about the other systems research from Microsoft Research, etc - what you are seeing in my posting history is me sharing my writing a few times (as permitted by HN rules)
[1] https://www.usenix.org/conference/osdi20/presentation/berg