Why there is no much change in the incremental backup size of level 0 and level 1 I'm implementing incremental backup in my database. As per my knowledge after level 0 backup, level 1 backup will take only the backups of changes that are done. But in my db after level 0 full backup, level 1 backup is also taking the almost same backup size of level 0. 

On Friday, level 0 backup. Backup Size: 49.8 GB

BACKUP INCREMENTAL LEVEL 0 DATABASE PLUS ARCHIVELOG;

On Saturday, level 1 backup. Backup Size: 45.2 GB

BACKUP INCREMENTAL LEVEL 1 DATABASE PLUS ARCHIVELOG;

Is there any mistake which I have done here in the RMAN command. Please help.....
But in my db after level 0 full backup, level 1 backup is also taking
  the almost same backup size of level 0.


Verify if the backup generated in level 0 exists there in the location, while level 1 backup occurs.

The level 0 backup might have got deleted or removed from the location. This might be the reason for this issue.