A common requirement in realtime apps is to insert business logic into a message processing pipeline. Rather than offering our own functions, Ably supports these use-cases by providing a reliable gateway to invoke cloud functions or further process messages via the best available cloud services.

This is a journey of obscure settings, red herrings, and poll vs. epoll. A story of how I had spent a couple days performance profiling and optimizing some Elixir code, only to discover

Apache Cassandra is trusted to scale at internet level and designed to scale without limits. But a series of incidents in 2020 disrupted our Cassandra instllation. A cautionary tale of using Counters at scale in production, and how we restored our trust in Cassandra.

Diff algorithms are the basis of many everyday developer tools such as Git. But there's limited knowledge on the subject. Here we collate our research to provide systematic knowledge on deltas and diffs.