Thursday, September 18, 2014


I was reading through an old book recently and it said that you could not put a tablespace into hot backup mode if the database was in NOARCHIVELOG mode. This seemed reasonable to me but I wondered what might happen if you tried to do this so I ran the following SQL in an Oracle 11.2 database:  

SQL> l
  1* alter tablespace users begin backup
SQL> /
alter tablespace users begin backup
ERROR at line 1:
ORA-01123: cannot start online backup; media recovery
not enabled

If this happens to you, you have two choices:
  •  Don't do it again OR
  • Put the database into ARCHIVELOG mode first.
I hope to be doing some more serious posts about hot backup and recovery in the near future.

Thursday, September 11, 2014

How to See When Your Database Was Opened

This was tested on Oracle 11.2: 

SQL> l
  1* select startup_time from v$instance
SQL> /