Not sure where we got the idea that MVCC code is useless in master. Alexei,
I know that you used the MVCC partition counters implementation in order to fix tx & atomic caches protocol issues. The MVCC WAL backpointer mechanics can and should be used when we will move transaction records logging from COMMITTING stage to PREPARING stage. Current cache entry versioning mechanics can be used to allow faster reads inside transactions, direct offheap scans and many other optimizations. We should work on processes to prevent such merges in the future, but not waste time reverting something that can be used for profit.
