What is Pmon process?

What is Pmon process?

Process Monitor Process (PMON) The process monitor (PMON) performs process recovery when a user process fails. PMON is responsible for cleaning up the database buffer cache and freeing resources that the user process was using.

What is Oracle background process?

The background processes consolidate functions that would otherwise be handled by multiple Oracle Database programs running for each user process. They monitor other Oracle Database processes to provide increased parallelism for better performance and reliability.

What is MMON process in Oracle?

MMON (Manageability Monitor) is a background process that gathers memory statistics (snapshots) and stores this information in the AWR (automatic workload repository). MMON is also responsible for issuing alerts for metrics that exceed their thresholds. This process was introduced in Oracle 10g.

What is Oracle checkpoint process?

Answer: The checkpoint process is responsible for updating file headers in the database datafiles. A checkpoint occurs when Oracle moves new or updated blocks (called dirty blocks) from the RAM buffer cache to the database datafiles.

What is the difference between Smon and Pmon processes?

PMON is the Process Monitor which is responsible for recovering processes when the user process fails. PMON does the process cleanup. SMON is the System Monitor which is responsible for recovering the system after a failure.

What are the 5 mandatory background processes in Oracle?

This section describes the following mandatory background processes:

• Process Monitor Process (PMON)
• System Monitor Process (SMON)
• Database Writer Process (DBWn)
• Log Writer Process (LGWR)
• Checkpoint Process (CKPT)
• Manageability Monitor Processes (MMON and MMNL)
• Recoverer Process (RECO)

Should I end background processes?

While stopping a process using the Task Manager will most likely stabilize your computer, ending a process can completely close an application or crash your computer, and you could lose any unsaved data. It’s always recommended to save your data before killing a process, if possible.

What is Smon process in Oracle?

SMON (System MONitor) is an Oracle background process created when you start a database instance. The SMON process performs instance recovery, cleans up after dirty shutdowns and coalesces adjacent free extents into larger free extents. SMON wakes up every 5 minutes to perform housekeeping activities.

How do I start MMON?

Follow below steps to restart the MMON process:

1. Grant restricted session to public: This grant is required to avoid any impact on the sessions connecting to database.
2. Enable and disable restricted sessions.
3. Revoke the restricted session: revoke restricted session from public;
4. Check MMON process; ps -ef | grep mmon.

What is SQL checkpoint?

A checkpoint creates a known good point from which the SQL Server Database Engine can start applying changes contained in the log during recovery after an unexpected shutdown or crash.

Why is checkpoint used?

What is a Checkpoint? The checkpoint is used to declare a point before which the DBMS was in the consistent state, and all transactions were committed. During transaction execution, such checkpoints are traced. After execution, transaction log files will be created.