Oracle-background process

Oracle-background process
LGWR: writes log entries in log_buffer from log_buffer to log files. After writing, log_buffer space is released. The server process writes SQL commands of every user to log buffer, log entries are not simple SQL statements, but oracle translates some of its user's SQL statements or commands into log entries. When a checkpoint www.2cto.com occurs, DBWR is written, as a result, LGWR writes www.2cto.com SMON: instance recovery: Abnormal instance interruption, host power failure, shutdown abort media recovery: disk damage, track damage, array damage, accidental deletion of data files PMON: CKPT: checkpoint, oracle uses it to locate where to start recovery, and restore the instance from where the last checkpoint occurred. SCN and checkpoint number: SCN: system change number are used to identify the transaction sequence. in oracle, General numbers are from SCN numbers, and check point numbers are also from SCN numbers, when a checkpoint occurs, the checkpoint number is equal to the SCN number of that point. select dbms_flashback.get_system_change_number () from dual; select current_scn from v $ database; select name, checkpoint_change # from v $ datafile; Archiver (ARCn): archiving process