PostgreSQL 10 High Performance - Third Edition

Terminology

There are several terms that you need to know in order to follow any discussion of warm or Hot Standby setups:

• Write-ahead log (WAL): PostgreSQL writes information to a series of WAL files, in segments of 16 MB in size, before making corresponding changes to the database itself. If you start with an identical pair of databases, and apply the same WAL files to them, the resulting pair will also be identical since the WAL contains all changed data.
• Basebackup: A backup made of the database in a way that includes everything needed for the copy to go through crash recovery and be intact, even if files were changed during the time the backup was being made. This requires using the pg_start_backup and pg_stop_backup commands, as well ...