In a slightly different use case than what OP is describing, we keep track of createdAt and updatedAt in Rethink, order by those, and pick off from max(createdA

In a slightly different use case than what OP is describing, we keep track of createdAt and updatedAt in Rethink, order by those, and pick off from max(createdAt) in destination in order to fake restarting the feeds.