ORA-00472: PMON Process Terminated with Error ORA-00472 is a critical Oracle database error that occurs when the PMON (Process Monitor) background process terminates abnormally. PMON is responsible for cleaning up failed user processes, releasing locks, rolling back uncommitted transactions, and freeing system resources — making it indispensable to Oracle's normal operation. When PMON goes down, the entire database instance typically crashes, requiring immediate attention. Top 3 Causes 1. Operating System Resource Exhaustion When the OS runs out of memory, file descriptors, or semaphores, PMON cannot allocate the resources it needs and terminates. Misconfigured kernel parameters are a very common root cause on Linux/Unix systems. -- Check current process and session usage vs.…