Does 'LGWR' writes to online redo log files strictly in circular fashion? Does 'LGWR' writes to online redo log files strictly in circular fashion? I saw this sentence from Oracle documentation. 


  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.


Does that means some redo log files could be skipped when LGWR writes to them?

Thanks.
Yes it does - Online Logfiles cannot be skipped because they are still ACTIVE. This causes a wait event called checkpoint not complete, by the way.