Using replication to scale PostgreSQL

Replication can be used in many scaling scenarios. Its primary purpose of course is to create and maintain a backup database for the case of system failure. This is especially true for physical replication. However, replication can also be used to improve the performance of a solution based on PostgreSQL. Sometimes third-party tools can be used to implement complex scaling scenarios.

Scaling for heavy querying

Suppose there is a system that is supposed to handle a lot of read requests. For example, that could be an application that implements HTTP API endpoint supporting the auto-completion functionality on a web site. Each time a user enters a character in a web form, the system...