Re: Performance problems

Victor Engmark wrote:
> Victor Engmark wrote:
>
> > Hello,
> >
> > Are there any planned speed increases for Chiba? I changed today from 
> > a ~12kb test file 
> > <http://isscvs.cern.ch/cgi-bin/viewcvs-all.cgi/moi/XForms/Chiba/Installation%20package/MTF/input.xml?rev=1.2&cvsroot=moi&content-type=text/vnd.viewcvs-markup> 
> > to the 327kb production file 
> > <http://isscvs.cern.ch/cgi-bin/viewcvs-all.cgi/moi/XForms/Chiba/Installation%20package/MTF/input.xml?rev=1.3&cvsroot=moi&content-type=text/vnd.viewcvs-markup>. 
> > This slowed down Chiba to a pulp. Page loading times of up to 10 
> > seconds on a dual Pentium 4 1.4GHz...
> Scratch that; with the new instance file 
> <http://isscvs.cern.ch/cgi-bin/viewcvs-all.cgi/moi/XForms/Chiba/Installation%20package/MTF/input.xml?only_with_tag=HEAD&cvsroot=moi> 
> (455kb) loading times are upwards of 30 seconds! Any performance tips 
> would be greatly appreciated, as the system is to be presented today...
Victor,

couldn't find the associated form but maybe some general things.

you might help the processor by setting data you never intend to change 
or modify to readonly to avoid validations. if you additionally can move 
out parts of instance data into new instances and put these into their 
own models you can effectively cancel revalidation on the model, which 
is one expensive thing for larger instances.
same is true for the pure size of your forms and how much of your data 
you're displaying and using at a given time. if you show all your data 
in all levels of detail this will produce much larger output and makes 
updating  more expensive. by breaking your editing tasks on a pool of 
instance-data down and use maybe several different forms, the situation 
can be relaxed significantly. by loading instance data with submission 
replace="instance" and by using the ref attribute you can partial data 
from your actual much bigger instance file. sure, this solution requires 
much more planning and won't help you quickly for now.
please also make sure, that you've set stylesheet compilation in config. 
you'll find a switch there.
we're aware of the bad scalability and sure there are improvements 
planned. there's already a suggestion of how to do it - see 
http://sourceforge.net/tracker/index.php?func=detail&aid=1087194&group_id=20274&atid=320274
cause this is rather a patch of the core than a clean solution we still 
need some time to integrate this without challenging conformance and 
Chiba's usability for e.g. the client-side.
we're currently thinking and working on further improvements but as our 
resources are limited it may take some time. think we'll see some 
significant improvements in this area in 1.1
furthermore there are plans to allow javabeans als instance-data instead 
of DOM. this surely would be very convenient for large data-collections 
(such as i18n lists). but this change must be thoroughly planned and 
tested and also requires some refactorings of the instance class.
the mentioned patch shows that big performance gains can be made (think 
it was in the dimension of 700%) and further are possible but these 
changes are heart surgery and are not done in a day. on our optimistic 
days we still hope there once will be donations that allow us to push 
things forward more quickly.
i sorry, if you're having inconvienences through the current state but 
XForms is a demanding technology and the is known to be memory-hungry.
nevertheless good luck.


best,

Joern







> --
> Victor Engmark

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