Increse of redo log size

Question

Hi,
Please help me to increase the redo log size.
As i am in DB - oracle 10G and OS - Suse linux 10SP2
SQL> SELECT * FROM v$log;
    GROUP#    THREAD#  SEQUENCE#      BYTES    MEMBERS ARC STATUS
FIRST_CHANGE# FIRST_TIME
         1          1        358  157286400          2 YES INACTIVE
   2972903289 28-NOV-11
         2          1        359  157286400          2 YES INACTIVE
   2972957401 28-NOV-11
         3          1        357  157286400          2 YES INACTIVE
   2972839164 27-NOV-11
    GROUP#    THREAD#  SEQUENCE#      BYTES    MEMBERS ARC STATUS
FIRST_CHANGE# FIRST_TIME
         4          1        360  157286400          2 NO  CURRENT
   2973005629 29-NOV-11
SQL> SELECT * FROM v$logfile;
    GROUP# STATUS  TYPE
MEMBER
IS_
         4         ONLINE
/oracle/JID/origlogB/log_g14m1.dbf
NO
         4         ONLINE
/oracle/JID/mirrlogB/log_g14m2.dbf
NO
    GROUP# STATUS  TYPE
MEMBER
IS_
         3         ONLINE
/oracle/JID/origlogA/log_g13m1.dbf
NO
         3         ONLINE
/oracle/JID/mirrlogA/log_g13m2.dbf
    GROUP# STATUS  TYPE
MEMBER
IS_
NO
         2         ONLINE
/oracle/JID/origlogB/log_g12m1.dbf
NO
         2         ONLINE
    GROUP# STATUS  TYPE
MEMBER
IS_
/oracle/JID/mirrlogB/log_g12m2.dbf
NO
         1         ONLINE
/oracle/JID/origlogA/log_g11m1.dbf
NO
    GROUP# STATUS  TYPE
MEMBER
IS_
         1         ONLINE
/oracle/JID/mirrlogA/log_g11m2.dbf
NO
8 rows selected.
Please help me how to execute for the above query.
Thanks,
Hariharan

Answer 1

Hello
Complete step:
Step 1 SQL> select a.group#, a.member, b.bytes/1024/1024 mb from v$logfile a, v$log b where a.group# = b.group#;
This query will show current group with redo log members and their size.
Step 2 Make the last redo log CURRENT one
To find which group is current at this moment use following query
SQL> select group#, status from v$log;
GROUP#         STATUS
1                    CURRENT
2                    INACTIVE
3                    INACTIVE
4                    INACTIVE
Now as you can see that the first group is marked as current but we need to make group 4 as current. So force group 4 to become current one by switching log file. To switch log file use following query.
SQL> alter system switch logfile;
GROUP#         STATUS
1                     INACTIVE
2                    CURRENT
3                    INACTIVE
4                  INACTIVE
SQL> alter system switch logfile;
GROUP#        STATUS
1                     INACTIVE
2                     INACTIVE
3                     INACTIVE
4                    CURRENT
Step 3 Drop the first online redo log
After making the last online redo log file the CURRENT one, drop the first online redo log:
SQL> alter database drop logfile group 1;
Database altered.
Note:
Be aware that if you are going to drop a logfile group, it cannot be the current logfile group. However, where attempting to drop the logfile group resulted in the following error as a result of the logfile group having an active status:
SQL> ALTER DATABASE DROP LOGFILE GROUP 1;
ALTER DATABASE DROP LOGFILE GROUP 1
ERROR at line 1:
ORA-01624: log 1 needed for crash recovery of instance ORA920 (thread 1)
ORA-00312: online log 1 thread 1: ''
Easy problem to resolve. Simply perform a checkpoint on the database:
SQL> ALTER SYSTEM CHECKPOINT GLOBAL;
System altered.
SQL> ALTER DATABASE DROP LOGFILE GROUP 1;
Database altered.
Step 4 You need to re-create dropped online redo log group with different size. Use the following query to achieve this.
SQL> alter database add logfile group 1 ('<path>/origlogA/log_g11m1.dbf','<path>/mirrlogA/log_g11m2.dbf') size 200M reuse;
Database altered.
Step 5 Force another log switch
After re-creating the online redo log group, force a log switch. The online redo log group just created should become the "CURRENT" group:
SQL> select group#, status from v$log;
GROUP#         STATUS
1                     UNUSED
2                     INACTIVE
3                     INACTIVE
4                    CURRENT
SQL> alter system switch logfile;
SQL> select group#, status from v$log;
GROUP#         STATUS
1                      CURRENT
2                      INACTIVE
3                      ACTIVE
Step 6 # Loop back to Step 3 until all logs are rebuilt
After re-creating an online redo log group, continue to re-create (or resize) all online redo log groups until all of them are rebuilt.
Regards,
Rajan