If you have performance problems with a backup of a large PostgreSQL database, then you may consider incremental or differential backups.
An incremental backup is a backup of all files that have changed since the last full backup.
In order to perform a restore, you must restore the full backup and then each set of incremental changes.
A differential backup is a backup of all individual changes since the last full backup. Again, restore requires you to restore the full backup and then apply any changes since then.