Search notes:

Oracle: redo log file

A redo log file might either be

Oracle (that is: LGWR) writes to one redo log file at a time. This specific log file is called the current log file.

Identification of log files

Each redo log file is assigned a sequence number in every log switch.

Thus, each online and archived log file is uniquely identified by the sequence number.

The history of log files is found in v$log_history.

select
   value
from
   v$sysstat
where
   name = 'redo wastage';