These Stratified B-trees are basically multi-versioned variations of Fractal Trees (aka Cache-oblivious streaming B-trees). This paper even references the tokutek teams paper - http://www.cs.sunysb.edu/~bender/newpub/BenderFaFi07.pdf.
I wouldn't be surprised if the Tokutek guys implemented something very similar to this Stratified B-tree to implement MVCC.
I wouldn't be surprised if the Tokutek guys implemented something very similar to this Stratified B-tree to implement MVCC.