It is unclear from this if the packfiles are actually stored only in the database, it sounds like he is saying they are stored in the file system (and accessed from there for git operations), but there is a copy in the DB too (updated after transactions have committed? Or in the commit but after the local file?). So it sounds like they are keeping repo metadata in tables to speed up queries, manage parallel access, etc. That is sensible, but quite different to keeping every code change as an SQL database entry.