In the master-follower scenario, we can say that reads from the master provide immediate consistency. Immediate consistency is simply a guarantee that as soon as a piece of data is written successfully, it will be available to clients who are reading that data. There is no delay between writing data and being able to read it.
On the other hand, reads from the followers provide eventual consistency. Eventual consistency means that once the data is successfully written, it will, at some point in the future, become available for reads. There is no guarantee of how soon it will become available; the only guarantee is that the time will eventually come. Of course, in a healthy production deployment, the delay ...
