Ivan Shcheklein pisze: > Hi Antoni, > > > As far as I understand you use Sedna to transform document from one > representaion into another (XSLT like transformation). It's not the best > task for XQuery, and unfortunately for Sedna also. It needs a lot of > space to construct thousands of nodes. However, I should note that it > works far from optimal in this and anyway we should work to decrease > temporary memory consuming in such cases.
Indeed, it is an XSLT-like transformation, from XML to RDF, similar in spirit to the WEESA framework [1], though without the limitation that all XML data must be in memory. That's why I wanted to use XQuery, to move all the memory-intensive processing to the database and get a stream of SAX events that would allow me to produce RDF triples without any buffering. Now it seems that I simply moved the problem from RAM to disk, which renders the "novelty" of my approach somewhat dubious :|. I posted the original query in the mail that started this thread. Do you think it would be more efficient to drop the one great query for $x at $pos in /dblp/* and instead have a loop and post many smaller queries for $x at $pos in /dblp/*[fn:position() >= offset && fn:position() < offset + limit] or for $x at $pos in /dblp/*[fn:position = (offset to (limit+offset))] until some query returns an empty sequence? Will it be more efficient? Can sedna deal with the fn:position() functions effectively, or will it internally iterate over all results and return only the matching ones. Antoni Mylka [email protected] [1] http://www.ifi.uzh.ch/pax/uploads/pdf/publication/7/reif-www05.pdf ------------------------------------------------------------------------------ This SF.Net email is sponsored by the Verizon Developer Community Take advantage of Verizon's best-in-class app development support A streamlined, 14 day to market process makes app distribution fast and easy Join now and get one step closer to millions of Verizon customers http://p.sf.net/sfu/verizon-dev2dev _______________________________________________ Sedna-discussion mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/sedna-discussion
