After a rescan prevent checkpoints from a previous epoch
Fix race condition which happens on rescan: rescan
function resets all checkpoints for replicator databases.
However before new change feeds start processing all
documents from sequence 0, a checkpoint could
happen from an existing change feed, which would
effectively result in a range of documents being
skipped over.
Add an `epoch` ref to State. On rescan update
the epoch. Thread epoch through the change feed process
and callbacks, then only allow checkpoints from current
epoch.
JIRA: COUCHDB-2965
1 file changed
