alter system checkpoint;
alter system archive log all;
alter system archive log current
alter system switch logfile;
这几个命令,在备份和恢复中起到什么作用啊??
alter system archive log all;
alter system archive log current
alter system switch logfile;
这几个命令,在备份和恢复中起到什么作用啊??
强迫oracle进行以次检查点,确保所有提交的事务的改变都被写到磁盘数据文件上。
alter system archive log all;手工归档所有的日志文件组
alter system archive log current
手工归档活动的日志文件组。alter system switch logfile;
The SWITCH LOGFILE clause lets you explicitly force Oracle to begin writing to a new redo log file group, regardless of whether the files in the current redo log file group are full. When you force a log switch, Oracle begins to perform a checkpoint but returns control to you immediately rather than when the checkpoint is complete. To use this clause, your instance must have the database open. 开始写新的日志文件组。不管当前日志文件组是否满了。
是不是只会切换日志组,会不会立刻归档切换前的那个日志组呢???
这个命令具体启动什么作用,有什么好处呢