Performance problem on function-based index

Question

Hi guys,
I am having performance problems with the addition of new function-based indexes.
alter session set nls_comp='ANSI';
alter session set nls_sort='BINARY_CI';
* have to run this because the of case-insensitivity requirements
I have a view. for ex:
create or replace view view1
as
select * from emp1,user
where emp1.empno=user.empno
union
select * from emp2,user
where emp2.empno=user.empno
union
select * from emp3,user
where emp3.empno=user.empno and so on
When I run this it works with a full table scan. Then when i created a function-based index:
create index user_ix on
user(nlssort(empno,'NLS_SORT=BINARY_CI'));
analyze index user_ix compute statistics;
analyze table user compute statistics;
the view hangs. but when i run the individual select statements it works.
Do you guys have any idea on what's going on? Any advise is greatly appreciated.
Thanks.

Answer 1

LC is absolutely right. Brain cramp on my part.
On the other hand, I can't seem to coerce Oracle to apply a to_binary_double conversion as part of an implicit conversion.
var bin_dbl binary_double;
select to_binary_double(14) into :bin_dbl from dual;
SCOTT @ nx102 JCAVE9420> select * from emp where empno = :bin_dbl;
no rows selected
Elapsed: 00:00:00.14
Execution Plan
Plan hash value: 2949544139
| Id  | Operation                   | Name   | Rows  | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT            |        |     1 |    39 |     1   (0)| 00:00:01 |
|   1 |  TABLE ACCESS BY INDEX ROWID| EMP    |     1 |    39 |     1   (0)| 00:00:01 |
|*  2 |   INDEX UNIQUE SCAN         | PK_EMP |     1 |       |     0   (0)| 00:00:01 |
Predicate Information (identified by operation id):
   2 - access("EMPNO"=TO_NUMBER(:BIN_DBL))I'd expect that Oracle would try to convert the binary double to a number, not the other way around.
Justin