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Here’s a quick tip on how to resolve the error: ORA-01623: log 12 is current log for instance UNNAMED_INSTANCE_2 (thread 2) – cannot drop
One of the databases I manage needed to be migrated to a VM, and moved from an Oracle RAC to a Single Instance.
When I went to remove one of the redo log groups, I came across this error.
The solution was quite simple, I just had to disable thread 2 of the database.
See the commands below:
SQL> ALTER DATABASE DROP LOGFILE GROUP 12;
ALTER DATABASE DROP LOGFILE GROUP 12
*
ERROR at line 1:
ORA-01623: log 12 is current log for instance UNNAMED_INSTANCE_2 (thread 2) - cannot drop
ORA-00312: online log 12 thread 2: '/u02/app/oracle/oradata/flashdata/RTDSBR01/onlinelog/group_12.31001.987676637'
ORA-00312: online log 12 thread 2: '+DATA/RTDSBR01/ONLINELOG/group_12.595.1080201495'SQL> alter database disable thread 2;
Database altered.SQL> ALTER DATABASE DROP LOGFILE GROUP 12;
Database altered.
