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Re: Does SAX make sense?

• To: xml-dev@l...
• Subject: Re: Does SAX make sense?
• From: Miles Sabin <miles@m...>
• Date: Sat, 19 Apr 2003 13:35:09 +0100
• In-reply-to: <16033.14774.204829.217147@m...>
• References: <E196lKL-0001Uj-00@b...> <200304191239.01827.miles@m...> <16033.14774.204829.217147@m...>
• Sender: Miles Sabin <miles@m...>
• User-agent: KMail/1.5.1

David Megginson wrote,
> Miles Sabin writes:
> > For a one-shot application (ie. startup; process one document
> > instance; terminate) the classloading overhead for the DOM API can
> > be quite significant even with the most recent VMs. In some work
> > I've done lately I've seen DOM classloading account for as much as
> > 10% of wall clock time with the Sun 1.4.1_02 VM on Linux, Solaris
> > and the other one. SAX, being a much smaller API, is at an
> > advantage here.
>
> That's scary.  I meant just the time for object allocation when
> loading the XML document (a DOM tree contains a *lot* of objects).  I
> had not considered class loading overhead.

Well, I guess I should emphasize that the case I was talking about there 
was fairly esoteric.

In general, tho', it's not so much scary as inevitable. Consider a 
trivial document <foo>wibble</foo>. Now consider how many additional 
non-core classes and interfaces have to be dragged off disk, verified 
and initialized before you can do anything interesting with it via the 
DOM API. If the application itself is trivial, it shouldn't be all that 
surprising that DOM classloading has a measurable impact.

On the bright side, it's quite possible that one aspect of this,

  http://www.jcp.org/en/jsr/detail?id=202

(see esp. section 2.5) will improve things significantly.

Cheers,


Miles

• References:
  • Re: ANN: White Paper - "Using OWL to Avoid Syntactic Rigor Mortis"
    • From: Uche Ogbuji <uche.ogbuji@f...>
  • Re: Does SAX make sense?
    • From: Miles Sabin <miles@m...>
  • Re: Does SAX make sense?
    • From: David Megginson <david@m...>

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