CBO (10g): unable to estimate the good NL join cardinality

Question

Hi all,
In my 10.2.0.4 database, the CBO does not choose the good execution plan for the following query:
SELECT  A.CNACT, A.LCACT, I.CMECH, I.CAECH, I.CSOPT, T.COLAN, I.MTSNA
FROM TPOOIN_TT T, IAVOPE I, NATACF A
WHERE T.POTMP IN ('TABDJO_TT', 'TCLRJO_TT', 'TCORJO_TT','TDLVJO_TT', 'TEXEJO_TT', 'TOPEJO_TT')
AND INSTR(',' || T.LIMAR || ',', ',' || I.COMAR || ',', 1) != 0
AND T.COINT IN (I.COINC,I.COINF)
AND I.DATRA BETWEEN T.DATRA AND T.DAMAX
AND A.ID_CNACT = I.ID_CNACT;
The execution plan chosen by the CBO is the following:
SQL_ID  762utndb7xxsa, child number 0
SELECT     A.CNACT, A.LCACT, I.CMECH, I.CAECH, I.CSOPT, T.COLAN, I.MTSNA   FROM
TPOOIN_TT T, IAVOPE I, NATACF A  WHERE T.POTMP IN (:"SYS_B_00", :"SYS_B_01", :"SYS_B_02",               
    :"SYS_B_03", :"SYS_B_04", :"SYS_B_05")    AND INSTR(:"SYS_B_06" || T.LIMAR || :"SYS_B_07",
:"SYS_B_08" || I.COMAR || :"SYS_B_09", :"SYS_B_10") != :"SYS_B_11"    AND T.COINT IN (I.COINC,I.COINF)  
AND I.DATRA BETWEEN T.DATRA AND T.DAMAX    AND A.ID_CNACT = I.ID_CNACT
Plan hash value: 1994655966
| Id  | Operation                      | Name        | Starts | E-Rows | A-Rows |   A-Time   | Buffers | Reads  |
|   1 |  NESTED LOOPS                  |             |      1 |      1 |    100 |00:02:16.62 |      20M|    203K|
|   2 |   NESTED LOOPS                 |             |      1 |      1 |   6757K|00:02:35.45 |     585K|    203K|
|   3 |    TABLE ACCESS FULL           | NATACF      |      1 |   2919 |     61 |00:00:00.01 |       6 |      0 |
|   4 |    TABLE ACCESS BY INDEX ROWID | IAVOPE      |     61 |      1 |   6757K|00:02:35.47 |     585K|    203K|
|   5 |     BITMAP CONVERSION TO ROWIDS|             |     61 |        |   6757K|00:00:00.02 |     771 |    589 |
|*  6 |      BITMAP INDEX SINGLE VALUE | IAVOPE9_BMP |     61 |        |   1145 |00:00:01.92 |     771 |    589 |
|*  7 |   TABLE ACCESS FULL            | TPOOIN_TT   |   6757K|      1 |    100 |00:01:51.64 |      20M|      0 |
Predicate Information (identified by operation id):
   6 - access("A"."ID_CNACT"="I"."ID_CNACT")
   7 - filter((INTERNAL_FUNCTION("T"."POTMP") AND INSTR(:SYS_B_06||"T"."LIMAR"||:SYS_B_07,:SYS_B_08||"I".
              "COMAR"||:SYS_B_09,:SYS_B_10)<>:SYS_B_11 AND ("T"."COINT"="I"."COINC" OR "T"."COINT"="I"."COINF") AND
              "I"."DATRA">="T"."DATRA" AND "I"."DATRA"<="T"."DAMAX"))
Note
   - dynamic sampling used for this statement
if I use the hint ORDERED, the query runs instantly.
Apparently, the CBO is mistaken when it estimates the join cardinality for NATACF and IAVOPE tables.
Indeed, it estimates that the NESTED LOOP is going to return only a single row (column E-Rows) instead of 6757K rows (column A-Rows).
By looking at the 10053 trace file we can see that the CBO is unable to estimate the join cardinality:
Join order[4]:  NATACF[A]#1  IAVOPE#2 TPOOIN_TT[T]#0
Now joining: IAVOPE[I]#2
NL Join
Outer table: Card: 2919.00 Cost: 26.27 Resp: 26.27 Degree: 1 Bytes: 24
Inner table: IAVOPE Alias: I
Access Path: TableScan
NL Join: Cost: 793981231.57 Resp: 793981231.57 Degree: 1
Cost_io: 775301479.00 Cost_cpu: 553603549165062
Resp_io: 775301479.00 Resp_cpu: 553603549165062
****** trying bitmap/domain indexes ******
Access Path: index (AllEqJoinGuess)
Index: IAVOPE9_BMP
resc_io: 2.00 resc_cpu: 15293
ix_sel: 0.016667 ix_sel_with_filters: 0.016667
NL Join: Cost: 5865.78 Resp: 5865.78 Degree: 1
Cost_io: 5864.00 Cost_cpu: 52626084
Resp_io: 5864.00 Resp_cpu: 52626084
Access path: Bitmap index - accepted
Cost: 5892.05 Cost_io: 5890.00 Cost_cpu: 60612251 Sel: 0.0000e+00
Not believed to be index-only
****** finished trying bitmap/domain indexes ******
Best NL cost: 5892.05
resc: 5892.05 resc_io: 5890.00 resc_cpu: 60612251
resp: 5892.05 resp_io: 5890.00 resp_cpu: 60612251
Join Card: 0.00 = outer (2919.00) * inner (62632660.00) * sel (0.0000e+00)
Join Card - Rounded: 1 Computed: 0.00
The cardinality of the inner and the outer table are well estimated but the CBO is using ZERO as the selectivity.
Does someone know why the CBO is making this estimation?
Is it a bug ?
thanks for your help                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   

Answer 1

I think there is a bug with DBMS_XPLAN beacause there are 2919 rows in NATACF table. This tabe is static.
My post concerns the fact that the CBO estimates 0 rows as the result of the join between IAVOPE and NATACF.
That's what I want to understand.
Join Card:  0.00 = outer (2919.00) * inner (62632660.00) * sel (0.0000e+00)The issue is not located on the temporary table since when I run a query with only NATACF and IAVOPE and I get the wrong estimation
select  A.CNACT, A.LCACT, I.CMECH, I.CAECH, I.CSOPT, I.MTSNA from IAVOPE I, NATACF A where
I.DATRA = to_date(:"SYS_B_0",:"SYS_B_1") AND A.ID_CNACT = I.ID_CNACT
Plan hash value: 2748866919
| Id  | Operation                     | Name        | Starts | E-Rows | A-Rows |   A-Time   | Buffers | Reads  |
|*  1 |  TABLE ACCESS BY INDEX ROWID  | IAVOPE      |      1 |      1 |    100 |00:00:00.24 |    9506 |      7 |
|   2 |   NESTED LOOPS                |             |      1 |      1 |  43580 |00:00:00.08 |      14 |      0 |
|   3 |    TABLE ACCESS FULL          | NATACF      |      1 |   2919 |      1 |00:00:00.01 |       4 |      0 |
|   4 |    BITMAP CONVERSION TO ROWIDS|             |      1 |        |  43579 |00:00:00.02 |      10 |      0 |
|*  5 |     BITMAP INDEX SINGLE VALUE | IAVOPE9_BMP |      1 |        |     15 |00:00:00.01 |      10 |      0 |
Predicate Information (identified by operation id):
   1 - filter("I"."DATRA"=TO_DATE(:SYS_B_0,:SYS_B_1))
   5 - access("A"."ID_CNACT"="I"."ID_CNACT")
Join order[1]:  NATACF[A]#0  IAVOPE#1
Now joining: IAVOPE[I]#1
NL Join
Outer table: Card: 2919.00 Cost: 26.27 Resp: 26.27 Degree: 1 Bytes: 24
Inner table: IAVOPE Alias: I
Access Path: TableScan
NL Join: Cost: 900314800.50 Resp: 900314800.50 Degree: 1
Cost_io: 875835670.00 Cost_cpu: 725477142751961
Resp_io: 875835670.00 Resp_cpu: 725477142751961
****** trying bitmap/domain indexes ******
Access Path: index (AllEqJoin)
Index: IAVOPE7_BMP
resc_io: 39.00 resc_cpu: 293786
ix_sel: 0.021477 ix_sel_with_filters: 0.021477
NL Join: Cost: 113896.21 Resp: 113896.21 Degree: 1
Cost_io: 113867.00 Cost_cpu: 865547968
Resp_io: 113867.00 Resp_cpu: 865547968
Access Path: index (AllEqJoinGuess)
Index: IAVOPE9_BMP
resc_io: 2.00 resc_cpu: 15293
ix_sel: 0.016129 ix_sel_with_filters: 0.016129
NL Join: Cost: 5865.78 Resp: 5865.78 Degree: 1
Cost_io: 5864.00 Cost_cpu: 52626084
Resp_io: 5864.00 Resp_cpu: 52626084
Access path: Bitmap index - accepted
Cost: 5892.05 Cost_io: 5890.00 Cost_cpu: 60612251 Sel: 0.0000e+00
Not believed to be index-only
****** finished trying bitmap/domain indexes ******
Best NL cost: 5892.05
resc: 5892.05 resc_io: 5890.00 resc_cpu: 60612251
resp: 5892.05 resp_io: 5890.00 resp_cpu: 60612251
Join Card: 0.00 = outer (2919.00) * inner (1408783.43) * sel (0.0000e+00)
Join Card - Rounded: 1 Computed: 0.00