PostgreSQL 11 Administration Cookbook

How it works…

The backup produced by the preceding procedure only allows you to restore to a single point in time. That point is the time of the pg_stop_backup() function.

A physical backup takes a copy of all files in the database (step 6—the base backup). That alone is not sufficient as a backup, and you need the other steps as well. A simple copy of the database produces a time-inconsistent copy of the database files. To make the backup time consistent, we need to add all of the changes that took place from the start to the end of the backup. That's why we have steps 5 and 7 to bracket our backup step.

In technical terms, steps 5 and 7 take advantage of the API that controls exclusive backups, meaning that there can only be one physical ...