[jdom-interest] Maximizing Effeciency of XPATH calls
paul at activemath.org
Fri Sep 9 12:54:26 PDT 2005
I'd be interested to know how much performance one can expect of such
engines... we keep processing XML but end-up storing and retrieving
with Lucene which has real good performances (like 1500 queries/second
with about 7000 items overall of 50Mb on a single PC, they are about 20
XML-databases that I try were way slower (by a factor of 10 or 100) but
I never went till a real index.
What does such a commercial produce as Mark Logic achieve ?
Le 9 sept. 05, à 19:08, Jason Hunter a écrit :
> I don't know how much data you have, but if it's a lot you can use an
> indexed XQuery engine to do the evaluation (one that indexes what it
> sees during load time and optimizes XPath queries). MarkLogic's
> engine is free up to 50 Megs (see http://xqzone.marklogic.com for a
> download and
> http://xqzone.marklogic.com/howto/tutorials/technical-overview.xqy for
> a quick intro). I'm presently working for Mark Logic on a project for
> a customer with terabytes of XML.
> Kevin L. Cobb wrote:
>> I've recently been tinkering with the effeciency of a process I have
>> to take an XML document and apply a lot of XPATH expressions to the
>> Here is what I've done to maximize the effeciency of this process.
>> Hoping others will have other handy tricks up their sleeves or point
>> out any
>> glaring deficiency.
>> The basic algorithm of the process is this:
>> 1. Build a Map of the XPATH's to apply to the XML. The xpath
>> expression is cached as org.jdom.xpath.XPath objects
>> 2. For each XML document to apply the Map of xpath expressions to
>> 3. Build the Document object from the XML string 4.
>> Loop through the Map of XPath objects and apply each to the
>> 5 Next XML document
>> The things I've done to increase performance are:
>> 1. Cached the xpath expressions as org.jdom.xpath.XPath objects
>> 2. Ensure the use of the SAXParser,
>> 3. Make each xpath expression as effecient as possible. For
>> use /*/*/MyElement instead of //MyElement.
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