[Xsltforms-support] Performance Tips

[Gordon R. <gor...@co...>]

Hi

 

I was wondering if anyone has any tips for getting the best performance
out of my xsltforms implementation. I have an xform that runs reasonably
well on FF, Chrome and Safari, but which struggles on IE8. Whilst the
difference in timings can in some part be accredited to IE's poor
javascript engine I'm not satisfied that this is the whole reason.

 

The xform I've created has a single model and within that model there
are 99 bindings, it seems to be that there is a direct correlation
between the number of bindings and the performance of xsltforms. I want
all of my data to be constructed and submitted at one point in time, so
afaik that rules out splitting things into a separate model, although I
would be interested to know if I've missed a trick somewhere.

 

Profiling of xsltforms.js doesn't point to any single method taking a
long time to execute, rather it's the accumulation of the processing
that takes time. Some examples:

 

XFControl.prototype.valueChanged - each time a value is changed on the
form then the whole model is rebuilt. This means that in the case of my
xform there is a loop of 99 calls to XFBind.prototype.recalculate. For
any calculated bindings we then see a huge amount of calls around a
number of evaluate methods e.g. in my xform for 5 calculated bindings
there are 460 calls to LocationExpr.prototype.xPathStep. If I happen to
write some custom javascript to set a few values on my form then the
model is rebuilt each and every time. The method I use for setting a
value is $(selector).get(0).xfElement.valueChanged(value); perhaps there
is a more efficient way?

 

When I xf:insert on a repeat I see the model being rebuilt once, but the
recalculation happens twice (which obviously triggers a revalidation and
a refresh both times). Why go through the recalculation cycle more than
once? With a large model this has obvious impact.

 

Any tips from those using xsltforms in anger would be welcome.

 

Thanks,

Gordon

 

Gordon Rogers

Senior Developer

Corelogic Limited

www.corelogic.co.uk <http://www.corelogic.co.uk/> 

Tel:       0131 550 0447

Email     gor...@co...
<mailto:gor...@co...> 

 

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