Performance Tuning :: Why There Is No Row Resource Operation Information In Tkprof Output

why there is no "Row Source Operation" information when I trace a long and complicated SQL query (It takes at least 25 minutes ro run)?

However, I can get the "Row Source Operation" information for a simple SQL Query.

Here are the tkprof output for a simple query and complicated query:

tkprof Output for a simple query
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 13 0.00 0.00 0 16 0 173
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 15 0.00 0.00 0 16 0 173

Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 3139

Rows Row Source Operation
------- ---------------------------------------------------
173 TABLE ACCESS FULL MY_TABLE (cr=16 pr=0 pw=0 time=0 us)

Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 13 0.00 0.00
SQL*Net more data to client 24 0.00 0.00
SQL*Net message from client 13 5.33 5.47

Tkprof output for a complex query
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.38 0.40 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 0 0.00 0.00 0 0 0 0
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 2 0.38 0.40 0 0 0 0

Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 3139

No Row Source Operation information here Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 1 0.00 0.00
db file sequential read 73062 0.25 692.23
db file scattered read 16099 0.18 76.65
latch: shared pool 4 0.02 0.03
latch: cache buffers chains 3 0.04 0.04
latch free 16 0.00 0.00