Git's database internals III: file history queries

Exploring Git's internals with a focus on its function as a distributed database, the text delves into the intricacies of file history commands as queries to understand code evolution beyond basic commit messages. It discusses the optimization of these queries through various modes like simplified history, full history, and full history with simplified merges, each offering different levels of detail and performance trade-offs. The text highlights the importance of understanding the treesame concept, especially in the context of merge commits, and how these modes are applied to identify which changes are meaningful. It also explains the role of specialized data structures such as Bloom filters stored in the commit-graph file, which enhance the speed and efficiency of these queries by minimizing tree parsing. The document emphasizes the practical implications of these optimizations, particularly for large repositories and Git hosting services like GitHub, and previews future discussions on Git's role as a distributed database, specifically focusing on synchronization operations like git fetch and git push.