Detailed notes on failure detection, leader election, and consistency models (e.g., CAP theorem). Transaction Processing: Focus on Write-Ahead Logs (WAL) and recovery mechanisms. For the most up-to-date, legal access to Alex Petrov's Database Internals , the book is available via O'Reilly Media Akshat-Jain/database-internals-notes - GitHub

If you prefer markdown-based notes that are easier to search and often more recently updated than static PDFs, these repositories are top-tier. Design and Implementation of DuckDB Internals (DiDi) : One of the most recent resources (updated April 2026

labeled content-update are a good starting point.

Clone the repo locally. Check the issues tab for discussions about recent papers (e.g., "How does Amazon Aurora differ from the book's chapter on replication?").