Need to Programmatically Set IRR Filter on Date Field Due to APEX 4.1 Bug

Question

There may be another work around but, here is the problem that we are encountering...
We have a huge table that is partitioned on a DATE field and an IRR that reports on this table. By default, we want to show the most recent 3 days of data. There is a built-in filter for "is in the last 3 Days." Sounds Great! Unfortunately APEX generates the code using TIMESTAMP rather than DATE functions. As a result of this, the query does not perform partition pruning and, as a consequence, it is doing a full table scan which takes forever. Note the use of the "LOCALTIMESTAMP" function in the query that is generated by APEX for this filter:
SELECT   "BUSINESS_DATE",
         COUNT ( * ) OVER () AS apxws_row_cnt
  FROM   (SELECT   *
            FROM   (SELECT   *
                      FROM   position_delta_his p) r
           WHERE   ("BUSINESS_DATE" BETWEEN *LOCALTIMESTAMP*
                                            - NUMTOYMINTERVAL (:APXWS_EXPR_1,
                                                               'year')
                                        AND  *LOCALTIMESTAMP*)) r
WHERE   ROWNUM <= TO_NUMBER (:APXWS_MAX_ROW_CNT)If, instead, APEX used the SYSDATE function, as the underlying column is a DATE, this returns instantly, after partition pruning.
SELECT   "BUSINESS_DATE",
         COUNT ( * ) OVER () AS apxws_row_cnt
  FROM   (SELECT   *
            FROM   (SELECT   *
                      FROM   position_delta_his p) r
           WHERE   ("BUSINESS_DATE" BETWEEN *SYSDATE*
                                            - NUMTOYMINTERVAL (:APXWS_EXPR_1,
                                                               'year')
                                        AND  *SYSDATE*)) r
WHERE   ROWNUM <= TO_NUMBER (:APXWS_MAX_ROW_CNT)
The bug is that APEX should base the underlying function on the data type of the filtered column.
As a work around, if we create a filter where BUSINESS_DATE >= '4/13/2012' (three business days ago), again, this returns instantaneously. The issue is that we can only set this filter by using the APEX GUI. We need to be able to:
1. Determine the date for 3 business days ago
2. Set this as the default filter.
I tried creating a BEFORE HEADER PL/SQL page process but, it does not appear to be having any effect. Here is that code:
DECLARE
    ldt_Filter DATE;
    CURSOR lcsr_GetMaxBusinessDate IS
        SELECT Max(BUSINESS_DATE)
        FROM POSITION_DELTA_HIS;
    DAYS_AGO CONSTANT NUMBER := 3;       
BEGIN
    APEX_UTIL.IR_CLEAR( :APP_PAGE_ID );
    OPEN lcsr_GetMaxBusinessDate;
    FETCH lcsr_GetMaxBusinessDate INTO ldt_Filter;
    CLOSE lcsr_GetMaxBusinessDate;
    ldt_Filter := ( Trunc( ldt_Filter ) - 3 );
    APEX_UTIL.IR_FILTER( p_page_id       => :APP_PAGE_ID,
                         p_report_column => 'BUSINESS_DATE',
                         p_operator_abbr =>'GTE',
                         p_filter_value  => TO_CHAR( ldt_Filter, 'YYYYMMDDHH24MISS' ) );
END;Can anyone tell me:
1. How to set this filter programmatically (also needs to be displayed on the page so the user can see the current filter...as if it were created via the GUI) ***OR***
2. Some other work around for this issue..
Thanks,
-Joe

Answer 1

Actually, now that I look further, I don't think it is going to work to simply set the filter programmatically. The end user can still click the column heading where they are only given the choice of the LOCALTIMESTAMP based filters. If they pick one, the page is going to be out to lunch for them.
We really need some other fix. We really need a way to actually address the underlying issue.
-Joe