alter system switch logfile
和alter system archive log current的区别
alter system switch logfile 是强制日志切换，不一定就归档当前的重做日志文件（若自动归档打开，就归档前的重做日志，若自动归档没有打开，就不归档当前重做日志。）
晨字取名的寓意
alter system archive log current 是归档当前的重做日志文件，不管自动归档有没有打都归档。
这条命令导致Oracle切换到一个新的日志文件，当前联机重做日志文件归档， 并且为什么没有北瓜Oracle归档所有未被归档的重做日志文件。
主要的区别在于:孕妇能吃芒果么
ALTER SYSTEM SWITCH LOGFILE对单实例数据库或RAC中的当前实例执行日志切换;
而ALTER SYSTEM ARCHIVE LOG CURRENT会对数据库中的所有实例执行日志切换。started怎么读
为什么执行热备后要执行alter system archive log current 这个语句，看到很多脚本都是这样写的。是不是必须的？
一般的RMAN脚本都是这样写的，因为RMAN是可以备份归档日志的。
曼陀罗花花语alter system archive log current 这样后就可以将所有的归档都备份出来了。这样做是为了保证数据的完整和一致。
趵突泉作文ALTER SYSTEM SWITCH LOGFILE ;
SWITCH LOGFILE Clau
TheSWITCHLOGFILEclau 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 u this clau, your instance must have the databa open.
ALTER SYSTEM ARCHIVE LOG CURRENT ;
CURRENT Clau
Specify CURRENT to manually archive the current redo log file group of the specified thread, forcing a log switch. If you omit the THREAD parameter, then Oracle archives all redo log file groups from all enabled threads, including logs previous to current logs. You can specifyCURRENTonly when the databa is open.
ALTER SYSTEM ARCHIVE LOG CURRENT NOSWITCH;
NOSWITCH
SpecifyNOSWITCHif you want to manually archive the current redo log file group without forcing a log switch. This tting is ud primarily with standby databas to prevent data divergence when the primary databa shuts down. Divergence implies the possibility of data loss in ca of primary databa failure.万变不离其宗
情景剧表演
You can u theNOSWITCHclau only when your instance has the databa mounted but not open. If the databa is open, then this operation clos the databa automatically. You must then manually shut down the databa before you can reopen it
