Brief Introduction to Oracle Processes

Description of each process in Oracle

Important processes: SMON, PMON, DBWn, LGWR, CKPT, and ARCn

SMON: This process is used for data rediscovery. This process is mainly responsible for inspecting the system and cleaning the system,
PMON: Used to clear invalid connections, kill them, and create new necessary connections.

DBWn: Write the Data buffer cache in SGA to the dbf data file.
In these operations, execute:
The checkpoint is executed.
Dirty data reaches a certain level (to the data in SGA)
Reached a certain time (exceeds the time limit)
Tablespace offline, read_only, online, and other operations
The drop table operation will trigger

LGWR: used to write the redo log buffer in SGA to redo. log.
In these operations
Before Running DBWn
Execute the commit operation
When the log buffer is 1/3 full
When it exceeds 1 MB
Write Data every 3 seconds
 
CKPT: before writing data to data files, record the data in the control file.
Database recovery can be ensured. DBWn and LGWR both work during this operation,
Write data to data files and log files

ARCn: When archive log list (alter database archivelog/noarchivelog) is enabled.
The system writes the data in redo. log to the archive log. Used for rman data recovery