ORA-01624错误的处理-alter system checkpoint

SQL> alter database drop logfile group 2;

alter database drop logfile group 2

*

ERROR at line 1:

ORA-01624: log 2 needed for crash recovery of instance dbstat (thread 1)

ORA-00312: online log 2 thread 1: '/data1/dbstat/redo2.log'

SQL> alter system switch logfile;

System altered.

SQL> select * from v$Log;

GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIME

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

1 1 12 2147483648 1 NO ACTIVE 203704 2009-09-17 19:04:23

2 1 11 52428800 1 NO ACTIVE 203206 2009-09-17 18:56:08

3 1 13 2147483648 1 NO CURRENT 203710 2009-09-17 19:04:38

SQL> alter system checkpoint;



System altered.

SQL> select * from v$Log;

GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIME

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

1 1 12 2147483648 1 NO INACTIVE 203704 2009-09-17 19:04:23

2 1 11 52428800 1 NO INACTIVE 203206 2009-09-17 18:56:08

3 1 13 2147483648 1 NO CURRENT 203710 2009-09-17 19:04:38

SQL> alter database drop logfile group 2;

Database altered.

checkpoint由ckpt进程触发oracle进行checkpoint动作,将data buffer中的脏块(已经写在redo里记录但是没有写到datafile里的)的内容写入到data file里并释放站用的空间,由dbw后台进程完成,并修改controlfile和datafile的scn.

一般手工执行是由于要删除某个日志但是该日志里还有没有同步到data file里的内容,就需要手工check point来同步数据,然后就可以drop logfile group n.