I was thinking about logic of RMAN when doing incremental backups and not quite sure if I understand it right.
1) When doing "backup incremental level 0 database plus archivelog delete all input", I understand that RMAN takes Level 0 backup of the database + all archive logs that were generated during the backup + all archive logs that were generated before backup.
2) If I do then "backup incremental level 1 database plus archivelog delete all input" after level 0 was done, RMAN will take all changes to data files since L0 + all archive logs that were generated during the backup + all archive logs that were generated before backup but after L0.
The question here is about efficiency of these two approaches, do RMAN really need to take and keep "all archive logs that were generated before backup" in 1) case and "all archive logs that were generated before backup but after last L0" in 2) case? In my understanding this changes were already be presented as part of data files backup.
Could someone shed a light on this please.
Thanks