The job of MMON( Manageability Monitor) background process is to perform tasks like taking AWR snapshots and automatic diagnostic analysis.

Sometime, MMON process crashes or get suspended .

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

Enabling and disabling will start the MMON process.

3. Revoke the restricted session:

4. Check MMON process;