Restoring incremental backup of Postgres

Question

I have restored basic backup successfully of Postgres. However, after that I have tried to restore incremental backup of Postgres(it was a couple of write to test table), and it had a couple of WAL files and some WAL files with .backup at the end. I have tried to put them into my pg_wal archive directory, that I'm using in the following restore command at postgresql.conf:

wal_level = replica
max_connections = 100
archive_mode = on
archive_command = 'test ! -f /var/lib/postgresql/16/main/pg_wal/wal_archive/%f && cp %p /var/lib/postgresql/16/main/pg_wal/wal_archive/%f'
restore_command = 'cp /var/lib/postgresql/16/pg_wal/wal_archive/%f %p

After putting them into /var/lib/postgresql/16/pg_wal/wal_archive I have tried to restart a couple times postgresql, however my new added WAL files still was not applied. Worth to mention that it seems like restarts did not trigger recovery mode, as restore_command usually executed from that mode.

Any help or advices is greatly appreciated!

Answer 1

What you describe is not an incremental backup; what you are trying to do is called "point in time recovery", which you initiate by placing a recovery.signal in the Postgres data directory and restarting the server. There are more details to how that works, which you can find in the docs.

Until the incremental backup/restore functionality makes it to Postgres 17, the only other option is to use pgBackRest.

• Laurenz Albe: Incremental backup has already made it into v17.
• mustaccio: Yeah byt v17 hasn't made it to the release yet, has it?
• Laurenz Albe: Right. Perhaps I misunderstood; it sounded like you were saying that it isn't in v17 yet.