A deep dive into Git internals: objects, blobs, trees, commits, the index, HEAD, branches, refs, packfiles, reflogs, and what really happens when you run git commit.
A single long-lived JWT can't be both secure and convenient. Splitting it into a short-lived access token and a rotating, revocable refresh token is what makes logout, role changes, and theft detection possible at all.
Without help, the database has no way to know where a row is without looking at all of them. An index is that help — a separate structure that tells the database where to look instead of scanning every row.
