Oracle Manageability Monitor Lite Process (MMNL)

The Manageability Monitor Light process collects statistics about active sessions and stores them in the Active Session History (ASH) buffer.

These statistics include values such as

• user id,
• state,
• machine,
• SQL text

Some data is also collected from v$session and v$session_wait views.

The ASH is a rolling buffer in memory: new data overwrites old data when the buffer is full. However, before the old data is overwritten, Oracle Manageability Monitor Process (MMON) takes a snapshot and MMNL flushes (every 10th record of) the ASH buffer into the dba_hist_active_sess_history view in the AWR.

MMNL is a background process.