Pair it with this video to learn how fast we can read a file? are we limited by disk or cpu?

Fraud detection in transaction data is mostly SQL. Not machine learning, not graph databases, not whatever Gartner is hyping this year. SQL, run against the right tables, with the right joins, looking for the right shapes.

Shopify needs no introduction of their scale. They have an oversell protection to track inventory buld on Redis, using DECR and INCR. But data now is lived on 2 system, and this cannot be done in an atomic manner because state is persisted outside of MySQL. Operating and scaling Redis in region awareness also not easy. So they moved this to MySQL with SKIP LOCKED.

The American Express core payments ecosystem is a global platform relied on by Card Members and partners around the world. Every day, it processes live payment transactions that require high availability, low latency, and predictable performance. To achieve this, the platform is built around a cell-based architecture that isolates failures, maintains low-latency processing, and scales capacity without expanding the failure domain

DataDog regularly run a variety of gamedays to intentionally stress our platforms and learn how our systems and teams respond under real-world conditions. During that they discover when network latency increase, replica lag, primary failed and failover is no longer safe.

On Xmas 2024, Aura Frames API had problems under peak load, being unavailable for three hours. They implement multiple strategy to help improve Postgres performance significantly. We will learn all of that here: high cpu during vacum, increase latency, lag replica, index bloat due to high write. One of interested thing is they split heavy write tables to its own dedicated db, we cannot always do this, but if we can it reduce and isolated high load to that db only.

I’ve been using Git for so long and I just realized you can ignore files at three different levels and not just with .gitignore. The three files you can use to ignore files are: .gitignore, .git/info/exclude, ~/.config/git/ignore

How hard it’s to build a home made CPU? hard if you had to do the hardware component yourself. But assume if you can get the part. TD4 is a little 4bit CPU: 2 registers, 16 bytes ROM.Quite limited but still very cool and teaches a lot of principles of computer architecture.