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Does LGWR waits for the DBWR to update the changes to the datafiles before overwriting redo group?

edited Jul 14, 2025 2:28PM in Database Backup and Recovery (MOSC) 7 commentsAnswered

My database is in NOARCHIVELOG mode. And currently there are two duplexed redo log groups.

SQL> select * from v$log;

GROUP#    THREAD#  SEQUENCE#      BYTES  BLOCKSIZE    MEMBERS ARC STATUS           FIRST_CHANGE# FIRST_TIM NEXT_CHANGE# NEXT_TIME     CON_ID
     1          1        266  209715200        512          2 YES ACTIVE                18355544 26-JUN-25     18359516 26-JUN-25          0
2 1 267 209715200 512 2 NO CURRENT 18359516 26-JUN-25 9.2954E+18 0

SQL>

Now since the database is in noarchivelog mode so this is going to overwrite the GROUP 1 once the GROUP 2 is completely filled. Here I have a doubt - would LGWR wait for the DBWR process to write all the update to the datafile before overwriting the GROUP 1 redo log files?

Please help me out to resolve the doubt…

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