I understand that Cloud SQL ( Postgres) on-demand backup is incremental. when you restore an instance using this backup, the existing data is wiped off before the instance is restored with all new data. in other words, the "backup" process is incremental but there is no way to restore only a specific incremental backup into an instance
Please, can you confirm if the aforementioned understanding is right?
Indeed, Cloud SQL backups are incremental. Taken from the Documentation:
Backups for Second Generation instances are incremental; they contain only data that has changed since the previous backup was taken. This means that your oldest backup is a similar size to your database, but the sizes of subsequent backups depend on the rate of change of your data. When the oldest backup is deleted, the size of the next oldest backup increases so that a full backup still exists.
Yet, Cloud SQL stores up to seven automated backups for each instance. This in fact allows you to restore to any specific backup, but of course, you will be delete all the data on the instance in order to restore the one in the backup.
If you are asking if it will be possible to restore only the incremental differences of an specific backup, then no, it is not possible. And it is also meant that way by the concept of Incremental Backups. You see, by definition, the incremental backup must have all the backups before. So, by restoring an "specific incremental backup into an instance" you are restoring the fullback + all the incremental backups up to the incremental backup you are requesting.
