Re: [xml-dev] [Summary] Eager and Just-in-Time loading of XML Schema doc

[Mukul Gandhi <gandhi.mukul@gmail.com>]

On Sat, Aug 7, 2010 at 9:44 PM, Michael Glavassevich
<mrglavas@ca.ibm.com> wrote:
> It can reduce memory usage.

I would now agree to this :)

I'm not sure if Xerces-J does any kind of "just in time" loading of
schema documents. Or does it has any? I think you wrote in an earlier
thread, that Xerces-J loads the whole of hierarchy of schema documents
eagerly. I have not heard of any user comments, if eager loading of
schemas have had any performance or memory problems to them (perhaps
user's don't notice this, due to generally better hardware we have
these days).

I'm a little skeptical of incurring significant (looks like to me)
design changes to schema validator design to accommodate "just in
time" loading, to satisfy a tiny fraction of the use-cases.

> In a long running application the (time) cost of schema loading can be made
> insignificant if the API (e.g. JAXP 1.3 Validation [1] or Xerces' grammar
> pools [2]) you're using caches the schema it loaded in memory and allows you
> to reuse that "compiled" result for validation. But if you're loading the
> same schema over and over again on each validation episode it can be very
> expensive and have seen many scenarios (particularly industry standards)
> where the set of schema documents are several orders of magnitude larger
> than the typical instance documents being validated.

I agree and thanks :)



-- 
Regards,
Mukul Gandhi