System altered
SQL> select group#,status from v$log;
GROUP# STATUS
---------- ----------------
1 CURRENT
2 INACTIVE
3 ACTIVE
SQL> alter system switch logfile;
System altered
SQL> select group#,status from v$log;
GROUP# STATUS
---------- ----------------
1 ACTIVE
2 CURRENT
3 ACTIVE
法二：
理论：增量检查点没有全部写，所以checkpoint_change#没有马上更新；但完全检查点，因为全部写，checkpoint_change#会马上更新。
实验：
SQL> select checkpoint_change# from v$database;
CHECKPOINT_CHANGE#
------------------
1716093
SQL> alter system checkpoint;
System altered
SQL> select checkpoint_change# from v$database;
CHECKPOINT_CHANGE#
------------------
1716275
法三：
实验：
SQL> show parameter log_checkpoints_to_
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
log_checkpoints_to_alert boolean FALSE
SQL> alter system set log_checkpoints_to_alert=true;
System altered
SQL> alter system checkpoint;
System altered
手工触发一个完全检查点，告警日志记录如下：
Thu Jun 07 01:27:17 2012
Beginning global checkpoint up to RBA [0x2d.1e4.10], SCN: 1716634
Completed checkpoint up to RBA [0x2d.1e4.10], SCN: 1716634
接下来手工触发一个增量检查点：
SQL> alter system switch logfile;
System altered
告警日志如下：
Thu Jun 07 01:28:15 2012
Beginning log switch checkpoint up to RBA [0x2e.2.10], SCN: 1716660
Thread 1 advanced to log sequence 46
Current log# 3 seq# 46 mem# 0: D:\ORACLE\PRODUCT\10.2.0\ORADATA\ORCL\ONLINELOG\O1_MF_3_7TQZWZOY_.LOG
Current log# 3 seq# 46 mem# 1: D:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\ORCL\ONLINELOG\O1_MF_3_7TQZX11D_.LOG
从这两个告警日志中，我们可以看到，完全检查点会马上将RBA下移，而增量检查点就会悠着点了。