In scenarios where it is required to achieve better performance, it is quite common to set up more servers that would handle additional load and copy the same data to them from a master server. In scenarios where high availability is required, this is also a typical solution to continuously copy the data to a standby server so that it could take over in case the master server crashes.
Data replication in PostgreSQL
Transaction log
Before explaining how to set up data replication, let's quickly look at how PostgreSQL handles changes in data at the lower level.
When PostgreSQL processes a command that changes the data in the database, it writes the new data on disk to make it persistent. There are two locations on disk...
