As we know, Dynamo uses vector clocks to remove conflicts while serving read requests. Now, if a replica falls significantly behind others, it might take a very long time to resolve conflicts using just vector clocks. It would be nice to be able to automatically resolve some conflicts in the background. To do this, we need to quickly compare two copies of a range of data residing on different replicas and figure out exactly which parts are different.

What are Merkle trees?

A replica can contain a lot of data