通过动态性能视图v$backup_set_details或v$backup_piece都可以查询RMAN每天的备份大小信息：
查询v$backup_set_details
select
to_char(start_time,'yyyy-mm-dd') start_time,
to_char(start_time,'day') day,
round(sum(OUTPUT_BYTES)/1024/1024/1024,2) SIZE_GB
from v$backup_set_details
group by to_char(start_time,'yyyy-mm-dd'),to_char(start_time,'day')
order by start_time desc;
查询v$backup_piece
select
to_char(start_time,'yyyy-mm-dd') start_time,
to_char(start_time,'day') day,
round(sum(BYTES)/1024/1024/1024,2) SIZE_GB
from v$backup_piece where handle is not null
group by to_char(start_time,'yyyy-mm-dd'),to_char(start_time,'day')
order by start_time asc;
