PostgreSQL 12 High Availability Cookbook - Third Edition

How it works...

We actually recommend applying the first rule to all clusters, as suggested in the Introducing indirection recipe. It's especially important here as the focus is specifically centered on maximizing availability.

Unlike a standard PostgreSQL node, a cluster containing multiple primary nodes does not require the promotion of alternate systems to writable status. This means we can switch to them in a nearly instantaneous manner. A properly configured proxy layer means this is possible without directly alerting the application layer. Such a cluster could resemble this diagram:

Given this configuration, it's possible to switch from ...