Performance question on looping thrue blocks and items (forms 10.1.2.3)

Question

Hi all,
I'm back again in Forms forum : ) !!! and I'm working on a new and very interesting project
version used : Forms [32 bits] Version 10.1.2.3.0 (Production)
A little question for gurus :
On former projects I used to call loops on blocks and item like shown below to do various things such as displaying buttons or showing canvas or different VA depending on the user or scenarios .
PROCEDURE FRM_BLK_ITM_LOOP IS
v_curblk varchar2(90); -- bloc courant
v_curitm varchar2(90); -- item courant
BEGIN
  v_curblk := get_form_property(:SYSTEM.CURRENT_FORM,first_block); -- on récupère le 1er block de la form
  LOOP
  v_curitm := v_curblk||'.'||get_block_property(v_curblk,first_item); -- on récupère le 1er item du block
    WHILE v_curitm != v_curblk||'.'||get_block_property(v_curblk,last_item)
     LOOP -- tant que l'item n'est pas le dernier du block on loop
        v_curitm :=  v_curblk||'.'||get_item_property(v_curitm,nextitem); -- on récupère l item suivant
        if get_item_property(v_curitm,<some property>) = 'TRUE' then
          --- I can do something.... or adding more conditions if then etc...
        end if;
    END LOOP;
  EXIT WHEN v_curblk = get_form_property(:SYSTEM.CURRENT_FORM,last_block); -- on sort losrqu on arrive au dernier block
  v_curblk := get_block_property(v_curblk, nextblock); -- on passe au block suivant
  END LOOP;
END;In my current project we work on quite huge forms which can have a consequent number of blocks and items.
And we must be very careful regarding performance issues as these forms are accessed via LAN and WAN.
So my question :
This method seems to be quite efficient as it goes thrue blocks and items sequences as they are defined in the builder comparing to go_block -> go_item ->do_something which can easily turn into nightmare-programming.
But I don't really know about network roundtrips with this kind of method.
Is everything done in the app server and then fetched to the client?
What triggers block-level and item-level can be fired during the execution of the loop ? and so one...
Thanks in advance for your advices on this matter.
Jean-Yves

Answer 1

Hmmm, I have to say I never bothered if Forms is in Socket mode or not; I enabled the network statistics, counted the roundtrips and looked for ways to get them lower (my old friend wireshark did also a good job regarding this) ;). But regarding the note Forms 6i uses Socket Connections by default, this might apply to 10g too (or the enhancement request was approved, who knows).
Frankly I am not entirely sure what Socket Mode means; I guess it's the mode the forms applet talks to the forms runtime; wheter it's stateful (via Sockets) or stateless (via HTTP / HTTPS) but this is just a wild guess, and I can't find informations on it quickly. I also enabled networkStats on my Developer Suite only, so I cannot tell if you can enable them on a full-fledged Application Server.
Anyway; as said I just counted the roundtrips and looked where I can avoid them when I made our application ready for WAN.
Another useful tool was Shunra VE Desktop which I used to simulate low bandwith networks with high latencys; I installed it on a virtual XP, started the application and tested how the Application performs. If something looked odd, I looked behind the scenes, built a little testform basing on the code behind and tried out various things; very often you can take advantage of the event bundling forms seems to make when you use several set_xyz calls as Francois also noted; e.g.
set_custom_property('bean_item', 1, 'PROPERTY', prop);
set_custom_property('bean_item', 1, 'PROPERTY', prop);
set_custom_property('bean_item', 1, 'PROPERTY', prop);
set_custom_property('bean_item', 1, 'PROPERTY', prop);
set_custom_property('bean_item', 1, 'PROPERTY', prop);
vRet := get_custom_property('bean_item', 1, 'PROPERTY);most certainly will cause just 1 roundtrip; but if you use get_custom_property in the middle of the set_custom_property calls you will encounter 2 roundtrips as forms needs to synchronize (you get a value from the bean so the forms runtime needs a response) with the forms applet whereas set_custom_property is a one-way-street which can be fired off simultaneous. The same applies to fbean.invoke and fbean.invoke_bool, fbean.invoke_char and the like. Of course if you are using more then one get_custom_property in this case the roundtrips will increase accordingly.
If you want to make use of event bundling make sure you fire off as much set_xyz as you can before forcing forms to synchronize (e.g. with get_xyz, or synchronize, create_timer,...)
cheers