日志组状态：inactive/active/current

日志组状态：inactive/active/current

 

Active (Current) and Inactive Redo Log Files

Oracle Database uses only one redo log files at a time to store redo records written from the redo log buffer. The redo log file that LGWR is actively writing to is called the current redo log file.

 

Redo log files that are required for instance recovery are called active redo log files.

--这句话的意思应该是：在上一个checkpoint event 之后到instance crash之间并且没有写入数据文件的这些redolog，这些redolog是instance crash 需要的，其状态为 active

 

 

Redo log files that are no longer required for instance recovery are called inactive redo log files.

 

If you have enabled archiving (the database is in ARCHIVELOG mode), then the database cannot reuse or overwrite an active online log file until one of the archiver background processes (ARCn ) has archived its contents. If archiving is disabled (the database is in NOARCHIVELOG mode), then when the last redo log file is full, LGWR continues by overwriting the first available active file.