oracle11g
观察数据库scn:
SQL> select dbms_flashback.get_system_change_number from dual;
GET_SYSTEM_CHANGE_NUMBER------------------------ 1025713SQL> select checkpoint_change# from v$database;CHECKPOINT_CHANGE#------------------ 1022214SQL>********************************
强制执行checkpoint:
SQL> alter system checkpoint;
System altered.SQL> select checkpoint_change# from v$database;CHECKPOINT_CHANGE#------------------ 1025732可以看到，此时 checkpoint_change# 比刚才的数据库scn 要大一些。这是因为数据库scn 随着时间的增长而增长。
SQL> select dbms_flashback.get_system_change_number from dual;
GET_SYSTEM_CHANGE_NUMBER------------------------ 1025755SQL> alter system checkpoint;System altered.SQL>
SQL> select checkpoint_change# from v$database;
CHECKPOINT_CHANGE#------------------ 1025765SQL> select name, checkpoint_change# from v$datafile; NAME--------------------------------------------------------------------------------CHECKPOINT_CHANGE#------------------/u01/app/oracle/oradata/orcl/system01.dbf 1025765/u01/app/oracle/oradata/orcl/sysaux01.dbf 1025765/u01/app/oracle/oradata/orcl/undotbs01.dbf 1025765NAME--------------------------------------------------------------------------------CHECKPOINT_CHANGE#------------------/u01/app/oracle/oradata/orcl/users01.dbf 1025765/u01/app/oracle/oradata/orcl/example01.dbf 1025765SQL> select name, checkpoint_change# from v$datafile_header;NAME--------------------------------------------------------------------------------CHECKPOINT_CHANGE#------------------/u01/app/oracle/oradata/orcl/system01.dbf 1025765/u01/app/oracle/oradata/orcl/sysaux01.dbf 1025765/u01/app/oracle/oradata/orcl/undotbs01.dbf 1025765NAME--------------------------------------------------------------------------------CHECKPOINT_CHANGE#------------------/u01/app/oracle/oradata/orcl/users01.dbf 1025765/u01/app/oracle/oradata/orcl/example01.dbf 1025765SQL>