WWW2009 EPrints

Inverted Index Compression and Query Processing with Optimized Document Ordering

This item is a Paper in the Search track.

Presentation

[img]Microsoft PowerPoint (770Kb)

Published Version

[img]
Preview
PDF (1080Kb)

Abstract

Web search engines use highly optimized compression schemes to decrease inverted index size and improve query through- put, and many index compression techniques have been stud- ied in the literature. One approach taken by several recent studies [7, 23, 25, 6, 24] first performs a renumbering of the document IDs in the collection that groups similar documents together, and then applies standard compression techniques. It is known that this can significantly improve index com- pression compared to a random document ordering. We study index compression and query processing tech- niques for such reordered indexes. Previous work has focused on determining the best possible ordering of documents. In contrast, we assume that such an ordering is already given, and focus on how to optimize compression methods and query processing for this case. We perform an extensive study of compression techniques for document IDs and present new optimizations of existing techniques which can achieve signif- icant improvement in both compression and decompression performances. We also propose and evaluate techniques for compressing frequency values for this case. Finally, we study the effect of this approach on query processing performance. Our experiments show very significant improvements in in- dex size and query processing speed on the TREC GOV2 collection of 25.2 million web pages.

Fun web stuff for this record

RKBExplorer (from linked data workshop)
URI: http://eprints.rkbexplorer.com/id/www2009/eprints-41
Browse the data for this paper at RKBExplorer
REST Interface
http://www2009.eprints.org/cgi/rest/eprint/41/
ORE Resource Map
ORE was described in the Linked Data Workshop. View Resource Map
Export Record As...

Repository Staff Only: item control page | Correct metadata | Add files

About this site

This website has been set up for WWW2009 by Christopher Gutteridge of the University of Southampton, using our EPrints software.

Add your Slides, Posters, Supporting data, whatnots...

If you are presenting a paper or poster and have slides or supporting material you would like to have permentently made public at this website, please email cjg@ecs.soton.ac.uk - Include the file(s), a note to say if they are presentations, supporting material or whatnot, and the URL of the paper/poster from this site. eg. http://www2009.eprints.org/128/

Add workshops

It's impractical to add all the workshops at WWW2009 by hand, but if you can provide me with the metadata in a machine readable way, I'll have a go at importing it. If you are good at slinging XML, my ideal import format is visible at http://www2009.eprints.org/import_example.xml

Preservation

We (Southampton EPrints Project) intend to preserve the files and HTML pages of this site for many years, however we will turn it into flat files for long term preservation. This means that at some point in the months after the conference the search, metadata-export, JSON interface, OAI etc. will be disabled as we "fossilize" the site. Please plan accordingly. Feel free to ask nicely for us to keep the dynamic site online longer if there's a rally good (or cool) use for it...

Fun Stuff

OAI:
WWW2009 EPrints supports OAI 2.0 with a base URL of http://www2009.eprints.org/cgi/oai2
JSON
The JSON URL is http://www2009.eprints.org/cgi/json?callback=function&eprintid=number

To prevent google killing the server by hammering these tools, the /cgi/ URL's are denied to robots.txt - ask Chris if you want an exception made.

Feel free to contact me (Christopher Gutteridge) with any other queries or suggestions. ...Or if you do something cool with the data which we should link to!

Handy Tools

These are not directly related to the EPrints set up, but may be of use to delegates.

Social tool links
I've put links in the page header to the WWW2009 stuff on flickr, facebook and to a page which will let you watch the #www2009 tag on Twitter. Not really the right place, but not yet made it onto the main conference homepage. Send me any suggestions for new links.
SplashURL.net
When demoing live websites, use this tool to shorten the current URL and make it appaer real big, your audience can then easily type in the short URL and get to the same page as you. Available as a javascript bookmark