ORA-01861 occurs when NO_INDEX hint removed

Question

Hi all,
We've got a view that is very slow and we'd noticed it had several /* NO_INDEX (+index_name+) */ hints. Thinking this was an odd approach and may be causing the performance hit, I tested the query without the hints and, as expected, performance was vastly improved.
However, the application that uses the view queries via a DATE column on the view. When a date is specified in a query against the view, the version with the hints removed now comes up with ORA-01861. The same query against the view with the hints intact works fine (albeit very slowly).
The view references views/tables that are accessed across a database link. The source of the DATE field is originally a VARCHAR2 field that is converted to a date using TO_DATE on one of the views in the main view's FROM clause (to the DD/MM/YYYY HH24:MI:SS format).
I've tried all manner of TO_CHAR, TO_DATE (with and without TRUNC) to get the query to work without success. There is something very odd going on here.
The database is 9i.
Please help!

Answer 1

Many thanks for the swift responses.
The main query (I've posted the version with the hint so you can see that) is:
CREATE OR REPLACE FORCE VIEW people.xxmod_int_fp_shift_payment_v (psp_cust_id,
psp_person_id,
psp_term_date,
psp_pp_date,
psp_amt,
psp_ind,
psp_percent,
psp_hrs,
psp_pen_amt
AS
SELECT /*+ NO_INDEX(xienav.peev pay_element_entry_values_f_n50) */
xipciv.customer_id, papf.employee_number, papf.effective_end_date,
xienav.week_ending_date, NULL, NULL, NULL, NULL, NULL
FROM per_all_people_f papf,
per_all_assignments_f paaf,
pay_element_entries_f peef,
xxmod_int_ee_night_allow_v xienav,
xxmod_int_per_cust_id_v xipciv
WHERE paaf.person_id = papf.person_id
AND peef.assignment_id = paaf.assignment_id
AND xienav.element_entry_id = peef.element_entry_id
AND paaf.payroll_id = xipciv.payroll_id
AND peef.effective_start_date BETWEEN papf.effective_start_date
AND papf.effective_end_date
AND peef.effective_start_date BETWEEN paaf.effective_start_date
AND paaf.effective_end_date
UNION ALL
SELECT /*+ NO_INDEX(xienamv.peev pay_element_entry_values_f_n50) */
xipciv.customer_id, papf.employee_number, papf.effective_end_date,
xienamv.date_worked, NULL, NULL, NULL, NULL, NULL
FROM per_all_people_f papf,
per_all_assignments_f paaf,
pay_element_entries_f peef,
xxmod_int_ee_night_allow_mod_v xienamv,
xxmod_int_per_cust_id_v xipciv
WHERE paaf.person_id = papf.person_id
AND peef.assignment_id = paaf.assignment_id
AND xienamv.element_entry_id = peef.element_entry_id
AND paaf.payroll_id = xipciv.payroll_id
AND peef.effective_start_date BETWEEN papf.effective_start_date
AND papf.effective_end_date
AND peef.effective_start_date BETWEEN paaf.effective_start_date
AND paaf.effective_end_date
UNION ALL
SELECT /*+ NO_INDEX(xiesov.peev pay_element_entry_values_f_n50) */
xipciv.customer_id, papf.employee_number, papf.effective_end_date,
xiesov.date_worked, NULL, NULL, NULL, NULL, NULL
FROM per_all_people_f papf,
per_all_assignments_f paaf,
pay_element_entries_f peef,
xxmod_int_ee_shift_overtime_v xiesov,
xxmod_int_per_cust_id_v xipciv
WHERE paaf.person_id = papf.person_id
AND peef.assignment_id = paaf.assignment_id
AND xiesov.element_entry_id = peef.element_entry_id
AND paaf.payroll_id = xipciv.payroll_id
AND peef.effective_start_date BETWEEN papf.effective_start_date
AND papf.effective_end_date
AND peef.effective_start_date BETWEEN paaf.effective_start_date
AND paaf.effective_end_date;
One of the sub-view queries (they all do a similar thing) converting the data in question is:
CREATE OR REPLACE FORCE VIEW people.xxmod_int_ee_night_allow_v (element_entry_id,
early_hrs_to_2300,
late_hrs_from_2300,
pay_value,
week_ending_date
AS
SELECT /*+ NO_INDEX(peev pay_element_entry_values_f_n50) */
peev.element_entry_id, NULL, NULL, NULL,
TO_DATE (peev.screen_entry_value, 'YYYY/MM/DD HH24:MI:SS')
FROM pay_element_entry_values_f peev,
pay_input_values_f piv,
pay_element_types_f pet
WHERE piv.input_value_id = peev.input_value_id
AND piv.element_type_id = pet.element_type_id
AND pet.element_name = 'Night Allowance Non MOD'
AND piv.NAME = 'Claim Date'
AND peev.effective_start_date BETWEEN piv.effective_start_date
AND piv.effective_end_date
AND peev.effective_start_date BETWEEN pet.effective_start_date
AND pet.effective_end_date;
I've looked for erroneous data that may be contributing towards this error but I have yet to find any.