Use principle of group # In v $ log,

Use principle of group # In v $ log,
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The CURRENT group # Is 4,5, 6SQL> select group #, status from v $ log; GROUP # STATUS ---------- -------------- 4 INACTIVE 5 CURRENT 6 INACTIVE and then execute the following statement: alter database add logfile ('/arch/redo/redo7.log') size 1024 M; alter database add logfile ('/arch/redo/redo8.log') size 1024 M; alter database add logfile ('/arch/redo/redo9.log') size 1024 M; alter database add logfile ('/arch/redo/redo10.log') size 1024 M; ALTER DATABAS E add logfile ('/arch/redo/redo11.log') size 1024 M; alter database add logfile ('/arch/redo/redo12.log') size 1024 M; then: SQL> select group #, status from v $ log; GROUP # STATUS ---------- ---------------- 1 UNUSED 2 UNUSED 3 UNUSED 4 INACTIVE 5 CURRENT 6 INACTIVE 7 UNUSED 8 UNUSED 9 UNUSEDredo group when added, the principle of group # is to select (reuse) the group # when it is free from 1. Note that group # Is a db-level ID, not an instance-level ID. This is different from the management of datafile: The datafile number is not reused.