This post is a slightly expanded version of my earlier tweet. In software systems, "betting" is actually a common practice. One of the most common bets people place is retry. When the first attempt doesn't work, we can just "try it again". Retry is a bet – you are betting on…
In this post, we will show that a generic distributed critical section can't satisfy both safety and liveness properties with even a single faulty client process. System Model We assume a non-real-time system with no bound on process time or network delay. In the system, there exists a lock service…
This is a very practical paper. It focuses on practical matters such as admission control, non-uniform access patterns, metastability introduced by caches, etc. You won't find fancy distributed system algorithms in this paper. But it's an important paper which covers critical topics nonetheless. A system only delivers real value to…
This was one of my favorite posters at Meta (formerly known as Facebook)'s office. I don't have a picture of it on my phone, so I found one from the internet. I like to take ownership of problems that I run into, both at work, and in my personal…
For the entirety of this post, we assume a non-real-time system. First of all, why do we have TIMEOUT as a type of replies? What if we don't? This means, in some cases, either client or server (or both) can be "blocked" for an unbounded amount of time. With async…
This is a note on Louis Brandy and Nathan Bronson's talk at Systems @scale - https://www.facebook.com/atscaleevents/videos/5279535778820968/. Data generated from the customers are often schemaless (e.g. JSON), but fast SQL for analytical queries are desired out of this unstructured data. Having fast query performance…
This is a note on Databricks' SIGMOD '22 paper - Photon: A Fast Query Engine for Lakehouse Systems, which won the best industrial paper award. At a high level, the paper describes Photon, a vectorized query engine (written in C++) that adapts to the underlying unstructured data at run-time to…
You can leave comments on HN – https://news.ycombinator.com/item?id=31709501. In this post, I will talk about one way to figure out when to invalidate cache entries. I will use a specific setup as an example, which should still be general enough, and at the end of…