The recent history of changes in WiredTiger is represented by WT_UPDATE structures in the WiredTiger cache. As long as all updates after the stable timestamp are reachable, we could rollback to the stable timestamp by finding all of them and setting their txnid = WT_TXN_ABORTED. That makes those changes invisible to readers – i.e., it is equivalent to if the original transactions had rolled back instead of committing.
and WT_PAGE_DELETED and the lookaside table. We have
WT-3382 to address the former, and we should be able to read every page that is either in cache or needs a lookaside restore as part of the rollback operation.