ORA-01251 on system tablespace

Question

hi folks,
(of course we didn't have any backup)
when we try to open our DB we get:
SVRMGR> alter database open;
alter database open
ORA-01122: database file 19 failed verification check
ORA-01110: data file 19: '/tecdata/oradata/INVSID/system08.dbf'
ORA-01251: Unknown File Header Version read for file number 19
SVRMGR>
We find some recovery solution but not in case of system tablespace datafile
we cannot drop the datafile 'couse we are not able to open the database.
there is any solution?
thanks everyone!

Answer 1

Hello,
in dba_temp_files, it shows MAXBYTES as 34359721984, so UNLIMITED apparently does mean 32GB??As Sybrand posted, it depends on your Block Size.
If you use Smallfile Tablespace (the default) then, each of its Datafile is limited to *4 MBlock* (so 4x1024x1024 blocks). So, for a Block Size of 8 Ko it gives (8x1024)x(4x1024x1024) Bytes = *32 GB*. But, you may have up to *1022* Datafiles for your Tablespace.
So, if you want your Tablespace to extend more than 32 GB you may add other datafiles, up to *1022*. So in fact the maximum size for your Tablespace can reach almost *32 TB* (for a block size of 8 Ko). Of course, in this case, you'll have so many datafiles that it won't be easy to manage them.
This is the reason why, starting with Oracle 10.1 you may create Bigfile Tablespace. They have just one datafile but, it can reach *4 GBlock*, so 32 TB for a Block Size of 8 Ko.
Before using Bigfile Tablespace, you should ensure that your OS can support such large file else, the capacity of the Tablespace could be really limited.
Hope this help.
Best regards,
Jean-Valentin