LGWR is background database process which is responsible for redo log buffer cache to redo log file.
There are five critical situations when LGWR writes to log file:
- LGWR writes redo or changed information from redo log buffer cache to redo log files in the database.
- It is responsible for moving redo buffer information to online redo log files when you commit, and a log switch also occurs.
- LGWR writes to redo files when the redo log buffer is 1/3 rd full.
- It also writes for every 3 seconds.
- Before DBWR writes modified blocks to the datafiles, LGWR writes to the log file