In subversion writes replaced a node, then replaces the parent node all the way up to the root. So anyone doing a read in the middle of a merge only sees the ol

In subversion writes replaced a node, then replaces the parent node all the way up to the root. So anyone doing a read in the middle of a merge only sees the old data because it saw the old root node. I assume MVCC systems do something similar, but for others I would think a lock per node allows for a lot less contention. And your project then relies very much on good indexes to avoid reading rows and thus parent nodes you don’t need.