Forms Performance

 Here is a problem which is happening in forms 10.1.2.0.2

I have a block based on a from-clause query. I am constructing the 

where clause on the fly. 

 

if I do a search :

 

select *

from uw_clients

where lpad(pacmis_case_number,9,'0')='000642192';      -- function based index on table

 

performs great.

 

select *

from uw_clients

where erep_case_number='642192';                            -- regular index on table

 

performs great

 

 

then I do :

select *

from uw_clients

where lpad(pacmis_case_number,9,'0')='000642192'

or  erep_case_number='642192';

 

performance sucks.

 

It is only slow in forms, not in SQL/PLUS