drop logfile group ORA-01624: log 1 needed for crash recovery of instance ORA-00312

Before drop we should make sure atleast 3 redo group are there and dropping group should be in INACTIVE state.

SQL> alter database drop logfile group 3;

alter database drop logfile group 3

*

ERROR at line 1:

ORA-01624: log 3 needed for crash recovery of instance scvdev (thread 1)

ORA-00312: online log 3 thread 1: '/oradata/scvdev/datafile/scvdev/redo03.log'

So to make ACTIVE to INACTIVE execute system level checkpoint.

SQL> ALTER SYSTEM CHECKPOINT GLOBAL;

System altered.

SQL> alter database drop logfile group 3;

Database altered.

SQL> alter database add logfile group 3 ('/redolog/scvdev/onlinelog1/redo03a.log','/redolog/scvdev/onlinelog2/redo03b.log') size 512m;

Database altered.

SQL> select * from v$log;

    GROUP#    THREAD#  SEQUENCE#      BYTES  BLOCKSIZE   MEMBERS ARC

---------- ---------- ---------- ---------- ---------- ---------- ---

STATUS FIRST_CHANGE# FIRST_TIM NEXT_CHANGE# NEXT_TIME     CON_ID

---------------- ------------- --------- ------------ --------- ----------

1     1       10  536870912   512 2 NO

INACTIVE 710676 13-AUG-19       710679 13-AUG-19  0

2     1       11  536870912   512 2 NO

CURRENT 710679 13-AUG-19   2.8147E+14 0

3     1       0  536870912   512 2 YES

UNUSED     0     0 0