无论我们是用dbca建库，还是手工建。在完成了建库的任务后，有三个参数在以后的生产运用中非常重要，通常，我们是需要将其打开的。
  第一个是log_checkpoints_to_alert。
  SQL> show parameter checkpoint

  NAME                                 TYPE        VALUE
  ------------------------------------ ----------- ------------------------------
  log_checkpoint_interval              integer     0
  log_checkpoint_timeout               integer     1800
  log_checkpoints_to_alert             boolean     FALSE
  SQL> alter system set log_checkpoints_to_alert=true;

  System altered.
 
  第二个是archivelog mode
  SQL> shutdown immediate
  Database closed.
  Database dismounted.
  ORACLE instance shut down.
  SQL> startup mount
  ORACLE instance started.

  Total System Global Area  243269632 bytes
  Fixed Size                  1218748 bytes
  Variable Size              79693636 bytes
  Database Buffers          159383552 bytes
  Redo Buffers                2973696 bytes
  Database mounted.
  SQL> alter database noarchivelog;

  Database altered.

  SQL> alter database open;

  Database altered.

  SQL> archive log list      
  Database log mode              No Archive Mode
  Automatic archival             Disabled
  Archive destination            USE_DB_RECOVERY_FILE_DEST
  Oldest online log sequence     16
  Current log sequence           19
  SQL> shutdown immediate
  Database closed.
  Database dismounted.
  ORACLE instance shut down.
  SQL> shutdown mount
  SP2-0717: illegal SHUTDOWN option
  SQL> startup mount
  ORACLE instance started.

  Total System Global Area  243269632 bytes
  Fixed Size                  1218748 bytes
  Variable Size              79693636 bytes
  Database Buffers          159383552 bytes
  Redo Buffers                2973696 bytes
  Database mounted.
  SQL> alter database archivelog;

  Database altered.

  SQL> alter database open;

  Database altered.

  SQL> archive log list;
  Database log mode              Archive Mode
  Automatic archival             Enabled
  Archive destination     &nb