What is Schema Tracking? # In a distributed relational database system, like Vitess, a central component is responsible for serving queries across multiple shards. For Vitess, it is VTGate. One of the challenges this component faces is being aware of the underlying SQL schema being used. This awareness facilitates query planning. Table schemas are stored in MySQL’s information_schema, meaning that they are located in a VTTablet’s MySQL instance and not in VTGate.

Background # A critical vulnerability CVE-2021-44228 in the Apache Log4j logging library was disclosed on Dec 9. The project provided release 2.15.0 with a patch that mitigates the impact of this CVE. It was quickly found that the initial patch was insufficient, and an additional CVE CVE-2021-45046 followed. This has been fixed in release 2.16.0. Who is affected? # The bulk of vitess code is in golang, and is unaffected by these vulnerabilities.

Past - Frameworks without scale # Over the past couple of decades, there has been a steady rise in the complexity of the development stacks that the developers across the globe have been using. The web has advanced from being just HTML files, to also include CSS and JavaScript with their own multitudes of frameworks like Redwood, Next.js, and Angular, among many others. The number of library dependencies that each project has has also shot up, leading to package managers like npm gaining popularity.