High Performance Git

Git looks like a version-control tool. It is also a content-addressed database, a filesystem cache, a graph walker, and a transfer protocol.This book is about those layers and the performance costs of each one. It starts with objects, refs, the index, and history traversal, then moves outward into packfiles, maintenance, sparse working trees, partial clone, transport, repository scale, diagnosis, configuration, and recovery.It is written for engineers who need Git to stay fast as repositories, histories, and teams get larger: build and CI engineers, monorepo owners, developer-experience teams, and the people who wind up debugging strange Git behavior when the easy explanations stop working. Section 0 · Introduction Introduction Section I · Foundations Why Git gets slow, what Git stores, and how refs and the index steer through it. Why Git Performance Matters Git's Core Data Model Refs, HEAD, Reflogs, Index Section II · History and Rewrite How Git walks history and how rewrite commands reshape it without mutating commits. Revisions and History Traversal Merge, Rebase, Cherry-Pick, Rewrite Section III · Storage and Local Scale Object storage, index cost, maintenance, and the techniques that shrink local state. Loose Objects, Packfiles, Delta Compression The Index as a Performance Structure Commit-Graph, Bloom Filters, MIDX, Bitmaps Git GC and Maintenance Sparse-Checkout and Sparse-Index Section IV · Large-Repo Operations, Transport, and Scale Clone shape, transfer policy, parallel work with worktrees, repository size, and ref scale.