A brief history of backup label

For a long time, I remained ignorant about transaction logging mechanisms and PITR in PostgreSQL, although they were crucial in data durability. A better understanding of these concepts would have helped me in a previous life, to be more confident during a backup configuration and, well, during after-crash intervention!

By reading this post, I will come back to an amusing file that used to be a topic of discussion over the past decade: the backup label file. What is it and what is it used for? How has it be enhanced from its origin with PostgreSQL 8.0 and what could be expected from him over the next years?