To dump the current latch status use:
ALTER SESSION SET EVENTS 'immediate trace name controlf level level';
Levels (circa Oracle 8.1.5) are:
| Level | Description |
| 1 | Generic file header |
| 2 | Level 1 + database information + checkpoint progress records |
| 3 | Level 2 + reuse record section |
| 10 | Same as level 3 |
In later versions, level 15 appears to generate additional trace
The following ORADEBUG command has the same effect:
ORADEBUG DUMP CONTROLF level