[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message]

Re: XML tools and big documents

• From: David Megginson <david@m...>
• To: <xml-dev@i...>
• Date: Thu, 3 Sep 1998 10:00:44 -0400

Don Park writes:

 > > As for the memory issue, I have thought about some sort of LZW
 > > compression of all of the text in a document tree.  This would
 > > save a lot of memory, but may slow down building the DOM tree a
 > > bit.  Any ideas on this?
 > 
 > 
 > Your performance will suffer and memory problem still remains.

Agreed.  The overhead comes from the node objects, not from the text.
The biggest hogs can be attributes, especially in the standard SGML
DTDs which often include dozens of defaulted attributes for each
document type.  If you can optimise those (allocating nodes only on
demand and then freeing them as soon as they're not needed), you're
half-way there.

The second biggest hogs are leaf elements which contain only text.  If
you can treat those as special cases and allocate only one object for
each one instead of three (element node, node list, text node), then
you're another quarter of the way there.

PIs , doctype declarations, notations, etc. are rare enough that you
don't gain much by optimising them.  Your mileage on comments, entity
references and CDATA sections may vary, but you're probably best
skipping them or replacing them with their contents when you build the
tree, unless your application has very specialised requirements.


All the best,


David

-- 
David Megginson                 david@m...
           http://www.megginson.com/

xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i...
Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/
To (un)subscribe, mailto:majordomo@i... the following message;
(un)subscribe xml-dev
To subscribe to the digests, mailto:majordomo@i... the following message;
subscribe xml-dev-digest
List coordinator, Henry Rzepa (mailto:rzepa@i...)

• Follow-Ups:
  • Re: XML tools and big documents
    • From: Tyler Baker <tyler@i...>

• References:
  • Re: XML tools and big documents
    • From: "Don Park" <donpark@q...>

• Prev by Date: Re: XML tools and big documents
• Next by Date: Re: XML tools and big documents
• Previous by thread: Re: XML tools and big documents
• Next by thread: Re: XML tools and big documents
• Index(es):
  • Date
  • Thread