MinervaDB
How to use PgBouncer for implementing connection pooling in PostgreSQL?
PostgreSQL Internals – Hacking PostgreSQL Parser
PostgreSQL Freelists: Internals and Implementation
PostgreSQL CPU Cache Buffers Chains Latch: How to Monitor It
InnoDB MVCC: How It Is Implemented
MySQL 8 Biased Joins: How They Influence Query Performance
MySQL Histograms: What They Are and How They Are Used
MySQL Redo Log File Size: Tuning for Performance