Forms 9i/ DB 10g - Form Hangs when function is called

Question

Using 9i Web Forms on 10g Database Linux O/S
I have the following function call in a form within a loop:
:nbt02_lentrn.nbt_txn_descr := fn_get_trans_descr(ls_app_area_code,ls_txn_type);
The function being called contains this code:
FUNCTION fn_get_trans_descr(ps_app_area_code IN VARCHAR2,
ps_txn_code IN VARCHAR2) RETURN VARCHAR2 IS
CURSOR cur_txn_descr IS
SELECT descr
FROM financial_trans_types
WHERE code = ps_txn_code
AND aparea_code = ps_app_area_code;
ls_txn_descr financial_trans_types.descr%TYPE;
BEGIN
OPEN cur_txn_descr;
FETCH cur_txn_descr INTO ls_txn_descr;
CLOSE cur_txn_descr;
Return(ls_txn_descr);
END;
When the call is executed, the form hangs after the OPEN command. I have checked the parameters for their values and successfully executed the cursor in SQL.
When I hardcode the function parameter values, the code executes successfully. Also, and perhaps most unusually, if I do either of the following before the function call, the code runs successfully:
ls_txn_type     :=     ls_txn_type;
:nbt02_lentrn.nbt_txn_descr := fn_get_trans_descr(ls_app_area_code,ls_txn_type);
     ls_txn_type     :=     NVL(ls_txn_type,NULL);
:nbt02_lentrn.nbt_txn_descr := fn_get_trans_descr(ls_app_area_code,ls_txn_type);
I have also extracted the call and placed it into a different form where it works fine!
The variable ln_txn_type is populated via another call within the same loop. It's value alternates between null and a value for the record set.
The same code works fine Client/Server and although I have a solution, I'm not sure what the problem is! Does anyone have any clues?

Answer 1

Hello - your problem actually looks similar in symptoms to one I hit just a couple of days ago (see my post 'Forms hangs when using result of an OUT parameter to do an Insert ' on July 19th.)
The problem I was having was if I had a variable which already had a value, then passed into an IN OUT parameter of a db stored proc, the proc set the value to null, and then I tried to use the variable in a table insert. The form would just hang completely. Like you, one workaround for the problem was to have a line like:
my_var := NVL(my_var,NULL);
to somehow 'fix' the variable before trying to use it further. Even though the variable seems null, and returns true for IF ... IS NULL, something had gone wrong with it that rendered it toxic to my form. This workaround should have no net effect, but it does somehow solve the problem. Like your problem, mine doesn't occur on client server, only on the newer version.
I hit this problem using Forms 10g904, against a 9i database. Having talked it over with Oracle support, I've tried doing the same thing using 10g Release 2, and the problem disappears, so Oracle have obviously fixed it somewhere between the two releases - I'm currently investigating intermediate Patch Sets.
Don't know if this is helpful, but all I can suggest is that you ensure you've applied the latest patchsets to your Forms (you can try it on the Builder first before patching your apps server installation.) If that doesn't do it, I'm guessing it's a case of use the workarounds, or go up to a higher version altogether of Forms.
Sorry not to have any more optimistic advice!
James