From Oracle FAQ
Jump to: navigation, search

PMON (Process MONitor) is an Oracle background process created when you start a database instance. The PMON process will free up resources if a user process fails (eg. release database locks).

PMON normally wakes up every 3 seconds to perform its housekeeping activities. PMON must always be running for an instance. If not, the instance will terminate.

To speed-up housekeeping, one may also wake-up PMON (process 2 below) manually:

SQL> oradebug setmypid
SQL> oradebug wakeup 2

In Oracle releases prior to Oracle 12c, PMON also registered database serviced with the listener. This is now handled by the new LREG progress.

Check process[edit]

The following Unix/Linux command is used to check if the PMON process is running:

$ ps -ef | grep pmon
oracle   31144     1  0 11:10 ?        00:00:00 ora_pmon_orcl
Glossary of Terms
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z #