Different results for same query on different servers

Question

1. database being converted from 7.3.4 to 9.2
2. query is executed on both servers
3. different results!
The tables and data are the same, and indexes are setup on new server. EXPLAIN PLAN was run on both but with (predictably) widely different results.
I know, not much detail here, but has anyone ever ran into anything like this?
Thanks,
Pat

Answer 1

Folks,
Here is the relevant information for this problem. The attributes have been changed for confidentiality. If you need any other information let me know.
Thanks,
Pat
Query:
SELECT
one,two,three,four,a.five,six,seven,
a.eight,a.nine,
to_char(ten,'99999.99'),to_char(eleven,'99999.99'),
to_char(twelve,'99999.99'),to_char(thirteen,'99999.99'),
fourteen,fifteen,sixteen,seventeen,eighteen,
nineteen,twenty,twentyone
FROM
table1 a,
table2 b
WHERE
a.five = b.five
AND one = 'X'
AND six = ' '
AND three != 12345
AND three IN
(SELECT DISTINCT
three
FROM table3
WHERE
one = 'X'
AND twentytwo = 'XYZ'
AND twentythree != 0
AND twentyfour != 0
AND twentyfive = 'Y'
AND (a.five IN
(SELECT DISTINCT
five
FROM table1
WHERE
one = 'X'
AND three IN (12345)
Table1:
one          varchar2(1)     not null     PK
two          varchar2(20)     not null     PK
three          number(5)     not null     PK
four          number(2)     not null     PK
five          number(6)     not null     PK
six          varchar2(4)     not null     PK
seven          number(4)     not null
eight          varchar2(8)     not null
nine          date          not null
ten          number(7,2)
eleven     number(7,2)
twelve     number(7,2)
thirteen     number(7,2)
Table2:
five          number(6)     not null     PK
fourteen     varchar2(5)     not null
fifteen     varchar2(5)     not null
sixteen     varchar2(2)     not null
seventeen     varchar2(35)     not null
eighteen     varchar2(4)     not null
nineteen     varchar2(2)
twenty     varchar2(1)
twentyone     number(6)
Table3:
one          varchar2(1)     not null     PK
twentytwo     varchar2(12)     not null     PK
two          varchar2(20)     not null     PK
three          number(5)     not null     PK
four          number(2)     not null     PK
twentysix     number(2)     not null     PK
twentyfive     varchar2(1)     not null
nine          date          not null
twentythree     number(13,8)     not null
twentyfour     number(12,8)     not null
twentyseven     varchar2(1)     not null
eight          varchar2(8)     not null
Explain - Oracle9i (default, with CBO):
SELECT STATEMENT
RECURSIVE EXECUTION SYS_LE_3_0
RECURSIVE EXECUTION SYS_LE_3_1
TEMP TABLE TRANSFORMATION
HASH JOIN
HASH JOIN
HASH JOIN
TABLE ACCESS FULL SYS_TEMP_0FD9D6603_AB874A
TABLE ACCESS BY INDEX ROWID TABLE1
BITMAP CONVERSION TO ROWIDS
BITMAP AND
BITMAP MERGE
BITMAP KEY ITERATION
TABLE ACCESS FULL SYS_TEMP_0FD9D6603_AB874A
BITMAP CONVERSION FROM ROWIDS
INDEX RANGE SCAN TABLE1INDEX03
BITMAP MERGE
BITMAP KEY ITERATION
TABLE ACCESS FULL SYS_TEMP_0FD9D6602_AB874A
BITMAP CONVERSION FROM ROWIDS
INDEX RANGE SCAN TABLE1INDEX04
TABLE ACCESS FULL SYS_TEMP_0FD9D6602_AB874A
TABLE ACCESS FULL TABLE2
Query results - Oracle9i (with CBO):
X|A | 1| 0| 22| | 1|08-MAR-02|XYZ | | 24.00| | |ABCDE|FGHIJ|AB|ABCDEFG |ABC | | | |
X|B | 2| 1| 22| | 7|04-DEC-01|XYZ | | 3.25| 8.00| |ABCDE|FGHIJ|AB|ABCDEFG |ABC | | | |
X|C | 3| 1| 22| | 1|14-AUG-02|XYZ | | 10.35| | |ABCDE|FGHIJ|AB|ABCDEFG |ABC | | | |
X|D | 4| 1| 22| | 6|11-JUL-02|XYZ | | .00| 13.90| |ABCDE|FGHIJ|AB|ABCDEFG |ABC | | | |
X|E | 5| 5| 23| | 1|22-FEB-01|XYZ | | 211.80| | |ABCDE|EFGHI|AB|HIJKLMN |DEF | | | |
X|E | 5| 5| 23| | 1|22-FEB-01|XYZ | | 211.80| | |ABCDE|EFGHI|AB|HIJKLMN |DEF | | | |
X|E | 5| 5| 23| | 1|22-FEB-01|XYZ | | 211.80| | |ABCDE|EFGHI|AB|HIJKLMN |DEF | | | |
X|E | 5| 5| 23| | 1|22-FEB-01|XYZ | | 211.80| | |ABCDE|EFGHI|AB|HIJKLMN |DEF | | | |
X|E | 5| 5| 23| | 1|22-FEB-01|XYZ | | 211.80| | |ABCDE|EFGHI|AB|HIJKLMN |DEF | | | |
(approximately 4550 rows returned)
Explain - Oracle9i (ALTER SESSION SET OPTIMIZER_METHOD=RULE;):
SELECT STATEMENT
MERGE JOIN
SORT JOIN
NESTED LOOPS
NESTED LOOPS
VIEW VW_NSO_1
SORT UNIQUE
TABLE ACCESS BY INDEX ROWID TABLE3
INDEX RANGE SCAN TABLE3INDEXPK
TABLE ACCESS BY INDEX ROWID TABLE1
INDEX RANGE SCAN TABLE1INDEX03
TABLE ACCESS BY INDEX ROWID TABLE2
INDEX UNIQUE SCAN TABLE2INDEXPK
SORT JOIN
VIEW VW_NSO_2
SORT UNIQUE
TABLE ACCESS BY INDEX ROWID TABLE1
INDEX RANGE SCAN TABLE1INDEX03
Explain - Oracle 7.3.4:
SELECT STATEMENT
MERGE JOIN
SORT JOIN
NESTED LOOPS
NESTED LOOPS
VIEW
SORT UNIQUE
TABLE ACCESS BY ROWID TABLE3
INDEX RANGE SCAN TABLE3INDEX03
TABLE ACCESS BY ROWID TABLE1
INDEX RANGE SCAN TABLE1INDEX03
TABLE ACCESS BY ROWID TABLE2
INDEX UNIQUE SCAN TABLE2INDEXPK
SORT JOIN
VIEW
SORT UNIQUE
TABLE ACCESS BY ROWID TABLE1
INDEX RANGE SCAN TABLE1INDEX03
Query results - Oracle 7.3.4:
X|A | 1| 0| 22| | 1|08-MAR-02|XYZ | | 24.00| | |ABCDE|FGHIJ|AB|ABCDEFG |ABC | | | |
X|B | 2| 1| 22| | 7|04-DEC-01|XYZ | | 3.25| 8.00| |ABCDE|FGHIJ|AB|ABCDEFG |ABC | | | |
X|C | 3| 1| 22| | 1|14-AUG-02|XYZ | | 10.35| | |ABCDE|FGHIJ|AB|ABCDEFG |ABC | | | |
X|D | 4| 1| 22| | 6|11-JUL-02|XYZ | | .00| 13.90| |ABCDE|FGHIJ|AB|ABCDEFG |ABC | | | |
X|E | 5| 5| 23| | 1|22-FEB-01|XYZ | | 211.80| | |ABCDE|EFGHI|AB|HIJKLMN |DEF | | | |
(approximately 1150 rows returned)
Indexes (used):
TABLE1INDEX03     (three)
TABLE1INDEX04     (five)
TABLE2INDEXPK     (five)
TABLE3INDEXPK     (one,twentytwo,two,three,four,twentysix)
Discussion:
Notice the repeating result for X,E,5,5,23,.... in the Oracle9i retrieval using CBO.
The execution of this query returned approximately four times the number of rows as
Oracle 7.3.4 using RBO. This is a function of how many "fours" there are in table3
that have matching "threes and fours" in table1. If you put a DISTINCT clause at the
very front of the query (SELECT DISTINCT one,two,three ....) then the result is
accurate and the same as Oracle 7.3.4. In one execution of this query, 27,000 rows
are expected to be returned, but the server returned over 1 million rows!
When RBO was used on Oracle9i, the results were identical to the ones on Oracle 7.3.4.