Tuesday, November 08, 2011

Maxlogmembers in Oracle 9 and Oracle 10

In an earlier example, I looked at maxlogmembers. In Oracle 9, this limits the number of members allowed in any one redo log group:
 
SQL> select group#, members from v$log
  2  /
 
    GROUP#    MEMBERS
---------- ----------
         1          2
         2          2
         3          2
         4          2
 
SQL> select dimlm from x$kccdi
  2  /
 
     DIMLM
----------
         2
 
SQL> l
  1  alter database add logfile member
  2  '/disk3/test9/redo/log1c.rdo'
  3* to group 1
SQL> /
alter database add logfile member
*
ERROR at line 1:
ORA-00357: too many members specified for log file,
the maximum is 2
 
SQL>


In Oracle 10, the limit is still there but it is not applied:
 
SQL> select group#, members from v$log
  2  /
 
    GROUP#    MEMBERS
---------- ----------
         1          2
         2          2
         3          2
 
SQL> select dimlm from x$kccdi
  2  /
 
     DIMLM
----------
         3
 
SQL>
 
  1  alter database add logfile member
  2  'disk3/test10/redo/log1c.rdo'
  3* to group 1
SQL> /
 
Database altered.
 
SQL> alter database add logfile member
  2  'disk4/test10/redo/log1d.rdo'
  3  to group 1
  4  /
 
Database altered.
 
SQL> select group#, members from v$log
  2  /
 
    GROUP#    MEMBERS
---------- ----------
         1          4
         2          2
         3          2
 
SQL>
 
I believe that this change occurred in Oracle 10 Release 2 but I have not confirmed this.

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