System Monitor Process (SMON) : Oracle Background Process.
The System Monitor (SMON) process is one of the essential background processes in an Oracle database. It plays a crucial role in ensuring the database operates smoothly by handling a variety of tasks related to system maintenance and recovery. Below is an overview of the SMON process and its key functions:
Key Functions of the System Monitor Process (SMON)
The System Monitor (SMON) process is one of the essential background processes in an Oracle database. It plays a crucial role in ensuring the database operates smoothly by handling a variety of tasks related to system maintenance and recovery. Below is an overview of the SMON process and its key functions:
- Instance Recovery
- Cleaning Temporary Segments
- Coalescing Free Space
- Database Recovery Tasks
- Dictionary Management
- Offlining Unused Temporary Segments
- Rolling Back Dead Transactions
The system monitor process (SMON) performs many database maintenance tasks, including the following:
- Creates and manages the temporary tablespace metadata and reclaims space from orphaned temporary segments.
- Maintains the undo tablespace by onlining, offlining, and shrinking the undo segments based on undo space usage Statistics.
- Cleans up the data dictionary when it is in a transient and inconsistent state.
- Maintains the system change number (SCN) to time mapping table that is used to support Oracle Flashback features.