What is database replication?
Database replication is like having a backup generator in your home. The equipment that will ensure you continue getting your electricity supply even when the whole country is in blackout. In the world of databases, we always want to ensure that our databases run 24/7 without any issues or without downtime. To achieve this, some people ensure they come up with a backup plan. A replica of the main database is created and this replica stores up to date data of the original database. This replica is mostly hosted in a separate environment from the primary database so that in case the primary database goes down, the replica database takes over. Whenever the primary database and replica or secondary database are up to date with each other, we say these two are synchronized. Replication is achieved when these two are synchronized.
What is a replication issue?
Replication issue occurs when both the primary and secondary database fall out of sync. In this case the secondary database falls behind, and it no longer has the up to date data that is the same as the primary database. A real world example of this is the different time zones between continents or countries. We can say Chicago, USA and Nairobi, Kenya are out of sync with each other since these two are not in the same time zone.
