Restore datafile problem (RMAN)

Question

I delete the datafile branch.
Than restore it form the yesterdays backup
RMAN>restore tablespace branch.
successfully restored branch.dbf.
RMAN> recover tablespace branch;
archive log thread 1 sequence 12 is already on disk as file C:\ESAS\ORACLE\APP\O
RACLE\FLASH_RECOVERY_AREA\XE\ARCHIVELOG\2008_01_21\O1_MF_1_12_3S8KWFJM_.ARC
archive log thread 1 sequence 13 is already on disk as file C:\ESAS\ORACLE\APP\O
RACLE\FLASH_RECOVERY_AREA\XE\ARCHIVELOG\2008_01_21\O1_MF_1_13_3S8KWZM1_.ARC
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of recover command at 01/21/2008 10:20:57
RMAN-06053: unable to perform media recovery because of missing log
RMAN-06025: no backup of log thread 1 seq 5 lowscn 28752248 found to restore
RMAN-06025: no backup of log thread 1 seq 4 lowscn 28749190 found to restore
RMAN-06025: no backup of log thread 1 seq 3 lowscn 28735538 found to restore
RMAN-06025: no backup of log thread 1 seq 2 lowscn 28732630 found to restore
RMAN-06025: no backup of log thread 1 seq 1 lowscn 28704663 found to restore
RMAN-06025: no backup of log thread 1 seq 4 lowscn 28704627 found to restore
RMAN-06025: no backup of log thread 1 seq 3 lowscn 28684595 found to restore
RMAN-06025: no backup of log thread 1 seq 2 lowscn 28664563 found to restore
RMAN-06025: no backup of log thread 1 seq 1 lowscn 28642042 found to restore
RMAN-06025: no backup of log thread 1 seq 2225 lowscn 28640983 found to restore
RMAN-06025: no backup of log thread 1 seq 2224 lowscn 28640978 found to restore
RMAN-06025: no backup of log thread 1 seq 2223 lowscn 28633884 found to restore
SQL> alter tablespace branch online;
alter tablespace branch online
ERROR at line 1:
ORA-01190: control file or data file 4 is from before the last RESETLOGS
ORA-01110: data file 4: 'C:\ESAS\ORACLE\ORADATA\XE\BRANCH.DBF'
Also the size of the branch.dbf is 2,800GB normally, but when I restore it from the backupset it is nearly 500MB.

Answer 1

If you did a RESETLOGS 3 days ago, that would have been between
the SCNs 26840983 and 28642042 ! based on these lines :
RMAN-06025: no backup of log thread 1 seq 1 lowscn 28642042 found to restore
RMAN-06025: no backup of log thread 1 seq 2225 lowscn 28640983 found to restore
However you do not expect to see a 500MB file. So I wonder if Oracle found
no backup of the datafile from recent days but found the most recent backup to be of so long ago (3+ days) that the datafile then was only 500MB.
That would mean that your recent daily backups have been failing or silently erroring out.
If RMAN cannot find a most recent (eg yesterday's) backup of a datafile, it will go back in time till it can find the "lastest" backup -- so the "lastest" backup of that datafile was a 500MB image many days ago ?
Check your backup destination directory -- your FlashbackRecoveryArea to see if backups are really going there. Check your backup logs.