service could direct all writes to the single primary node, but distribute reads to one or more read replicas, as we see in Figure 11-6. The replication from the primary database to the replicas happens at some point after the write. This means that with this technique reads may sometimes see stale data until the replication has completed. Eventually the reads will see the consistent data. Such a setup is called eventually consistent, and if you can handle the temporary inconsistency it is a fairly easy and common way to help scale
