that’s a good news indeed. And yet another demonstration why it’s always a good idea to verify things against new releases.

Just for curiosity I tested in 11.1.0.6. In 11g it seems that we do not have to add the redundant expression into the order by clause. See below

SQL> create table requests ( subs_id number(10), insert_time date, processed number(3));

Table created.

SQL> create index fbi_requests_p
2 on requests
3 (case processed when 0 then mod(subs_id, 7) end);

Index created.

SQL> insert /*+ append */ into requests
2 select trunc(dbms_random.value(0, 10000)),
3 trunc(sysdate)+dbms_random.value(0, 1),
4 case when rownum commit;

Commit complete.

SQL> exec dbms_stats.gather_table_stats(user, ‘requests’, cascade => true);

PL/SQL procedure successfully completed.

SQL> select /*+ index(r fbi_requests_p) */ *
from requests r
where case processed when 0 then mod(subs_id, 7) end=:dequeue_process_number
order by insert_time
2 3 4 5
SQL> /

153 rows selected.

Execution Plan
———————————————————-
Plan hash value: 564389291

———————————————————————————————–
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
———————————————————————————————–
| 0 | SELECT STATEMENT | | 143 | 2145 | 6 (17)| 00:00:01 |
| 1 | SORT ORDER BY | | 143 | 2145 | 6 (17)| 00:00:01 |
| 2 | TABLE ACCESS BY INDEX ROWID| REQUESTS | 143 | 2145 | 5 (0)| 00:00:01 |
|* 3 | INDEX RANGE SCAN | FBI_REQUESTS_P | 143 | | 1 (0)| 00:00:01 |
———————————————————————————————–

Predicate Information (identified by operation id):
—————————————————

3 - access(CASE “PROCESSED” WHEN 0 THEN MOD(”SUBS_ID”,7) END
=TO_NUMBER(:DEQUEUE_PROCESS_NUMBER))

Statistics
———————————————————-
0 recursive calls
0 db block gets
5 consistent gets
0 physical reads
0 redo size
3278 bytes sent via SQL*Net to client
431 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
153 rows processed

SQL> drop index FBI_REQUESTS_P;

Index dropped.

SQL> create index fbi_requests_p
2 on requests
3 (case processed when 0 then mod(subs_id, 7) end,
4 case processed when 0 then insert_time end);

Index created.

SQL> exec dbms_stats.gather_table_stats(user, ‘requests’, cascade => true);

PL/SQL procedure successfully completed.

SQL> select /*+ index(r fbi_requests_p) */ *
2 from requests r
3 where case processed when 0 then mod(subs_id, 7) end=:dequeue_process_number
4 order by case processed when 0 then insert_time end;

153 rows selected.

Execution Plan
———————————————————-
Plan hash value: 1059845571

———————————————————————————————-
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
———————————————————————————————-
| 0 | SELECT STATEMENT | | 143 | 2431 | 95 (0)| 00:00:02 |
| 1 | TABLE ACCESS BY INDEX ROWID| REQUESTS | 143 | 2431 | 95 (0)| 00:00:02 |
|* 2 | INDEX RANGE SCAN | FBI_REQUESTS_P | 143 | | 2 (0)| 00:00:01 |
———————————————————————————————-

Predicate Information (identified by operation id):
—————————————————

2 - access(CASE “PROCESSED” WHEN 0 THEN MOD(”SUBS_ID”,7) END
=TO_NUMBER(:DEQUEUE_PROCESS_NUMBER))

Statistics
———————————————————-
171 recursive calls
0 db block gets
140 consistent gets
0 physical reads
0 redo size
3278 bytes sent via SQL*Net to client
431 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
4 sorts (memory)
0 sorts (disk)
153 rows processed