An index tree can be dumped using
ALTER SESSION SET EVENTS 'immediate trace name treedump level object_id';
where object_id is the object number of the index (in DBA_OBJECTS)
The tree dump includes
The following ORADEBUG command has the same effect
ORADEBUG DUMP TREEDUMP object_id
In Oracle 9.2 a treedump may crash if the index has been created by a primary / unique constraint e.g.
CREATE TABLE t1 (c1 NUMBER PRIMARY KEY);
or
CREATE TABLE t1 (c1 NUMBER); ALTER TABLE t1 ADD CONSTRAINT t1pk PRIMARY KEY (c1);
The treedump crashes when ind$.property > 256
This problem can be prevented by creating the index before creating the constraint