N.B. This page and the functionality described within is only applicable and relevant to Nutch 1.X.
Below is an example of running the new scoring and indexing systems from start to finish. This was done with a sample of 1000 urls and I ran two different fetch cycles. The first being 1000 urls and the second being the top 2000 urls. The loops job is optional but included for completeness. In production we have actually removed that job. This was done with a clean pull from Nutch trunk as of 2009-03-06 (right before 1.0 is set to be released). If anybody has any problems running these commands or has questions send me an email or send one to the nutch users or dev list and I will reply. Please send it to kubes at the apache address dot org.
bin/nutch inject crawl/crawldb crawl/urls/ bin/nutch generate crawl/crawldb/ crawl/segments bin/nutch fetch crawl/segments/20090306093949/ bin/nutch updatedb crawl/crawldb/ crawl/segments/20090306093949/ bin/nutch org.apache.nutch.scoring.webgraph.WebGraph -segment crawl/segments/20090306093949/ -webgraphdb crawl/webgraphdb |
One thing to point out here is that WebGraph is meant to be used on larger web crawls to create web graphs. By default it ignores outlinks to pages in the same domain, including subdomains, and pages with the same hostname. It also limits to one outlink per page to links in the same page or the same domain. All of these options are changeable through the following configuration options:
<!-- linkrank scoring properties --> <property> <name>link.ignore.internal.host</name> <value>true</value> <description>Ignore outlinks to the same hostname.</description> </property> <property> <name>link.ignore.internal.domain</name> <value>true</value> <description>Ignore outlinks to the same domain.</description> </property> <property> <name>link.ignore.limit.page</name> <value>true</value> <description>Limit to only a single outlink to the same page.</description> </property> <property> <name>link.ignore.limit.domain</name> <value>true</value> <description>Limit to only a single outlink to the same domain.</description> </property> |
But by default if you are only crawling pages within a domain or within a set of subdomains, all outlinks will be ignored and you will come up with an empty webgraph. This in turn will throw an error while processing through the LinkRank job. The flip side is by NOT ignoring links to the same domain/host and by not limiting those links, the webgraph becomes much, much more dense and hence there is a lot more links to process which probably won't affect relevancy as much.
bin/nutch org.apache.nutch.scoring.webgraph.Loops -webgraphdb crawl/webgraphdb/ bin/nutch org.apache.nutch.scoring.webgraph.LinkRank -webgraphdb crawl/webgraphdb/ bin/nutch org.apache.nutch.scoring.webgraph.ScoreUpdater -crawldb crawl/crawldb -webgraphdb crawl/webgraphdb/ bin/nutch org.apache.nutch.scoring.webgraph.NodeDumper -scores -topn 1000 -webgraphdb crawl/webgraphdb/ -output crawl/webgraphdb/dump/scores more crawl/webgraphdb/dump/scores/part-00000 -------------------------------------------------------------------------------- http://validator.w3.org/check?uri=referer 0.4955311 http://www.adobe.com/go/getflashplayer 0.4060498 http://www.statcounter.com/ 0.4060498 http://www.liveinternet.ru/click 0.33680826 http://www.adobe.com/products/acrobat/readstep2.html 0.31656843 http://www.adobe.com/go/getflashplayer/ 0.30378538 http://www.bloomingbows.com/2003/scripts/sitemap.asp 0.27821928 http://www.misterping.com/ 0.27821928 ... -------------------------------------------------------------------------------- bin/nutch readdb crawl/crawldb/ -stats -------------------------------------------------------------------------------- CrawlDb statistics start: crawl/crawldb/ Use GenericOptionsParser for parsing the arguments. Applications should implement Tool for the same. Statistics for CrawlDb: crawl/crawldb/ TOTAL urls: 16711 retry 0: 16686 retry 1: 25 min score: 0.0 avg score: 0.022716654 max score: 0.495 status 1 (db_unfetched): 15739 status 2 (db_fetched): 677 status 3 (db_gone): 75 status 4 (db_redir_temp): 143 status 5 (db_redir_perm): 77 CrawlDb statistics: done -------------------------------------------------------------------------------- bin/nutch generate crawl/crawldb/ crawl/segments/ -topN 2000 bin/nutch fetch crawl/segments/20090306100055/ bin/nutch updatedb crawl/crawldb/ crawl/segments/20090306100055/ rm -fr crawl/webgraphdb/ bin/nutch org.apache.nutch.scoring.webgraph.WebGraph -segment crawl/segments/20090306093949/ -segment crawl/segments/20090306100055/ -webgraphdb crawl/webgraphdb |
One thing that has been brought up is the -segment flag on webgraph. If you have more than one segment then you would use the -segmentDir flag available on the command line interface.
bin/nutch org.apache.nutch.scoring.webgraph.Loops -webgraphdb crawl/webgraphdb/ bin/nutch org.apache.nutch.scoring.webgraph.LinkRank -webgraphdb crawl/webgraphdb/ bin/nutch org.apache.nutch.scoring.webgraph.ScoreUpdater -crawldb crawl/crawldb -webgraphdb crawl/webgraphdb/ more crawl/webgraphdb/dump/scores/part-00000 -------------------------------------------------------------------------------- http://www.statcounter.com/ 1.7133079 http://www.morristownwebdesign.com/ 1.0093393 http://www.jdoqocy.com/click-3331968-10419685 0.87828785 http://www.anrdoezrs.net/click-3331968-10384568 0.87828785 http://www.sedo.com/main.php3?language=e 0.6565905 http://wetter.spiegel.de/spiegel/html/frankreich0.html 0.641775 http://www.kenwood.com/ 0.6084726 http://validator.w3.org/check?uri=referer 0.5605916 http://wetter.spiegel.de/spiegel/html/Italien0.html 0.5164927 http://www.youtube.com/?hl=en&tab=w1 0.50952965 http://www.addthis.com/bookmark.php 0.5013165 http://www.ptguide.com/ 0.49564213 http://www.adobe.com/go/getflashplayer 0.47368217 http://de.weather.yahoo.com/ITXX/ITXX0073/index_c.html 0.4657473 http://www.adobe.com/shockwave/download/download.cgi?P1_Prod_Version=ShockwaveFlash&promoid=BIOW 0.44376293 http://www.google.com/ 0.42282072 http://www.zajezdy.cz/ 0.41620353 http://www.intermarche.com/ 0.41489196 http://www.shipskill.com/7/ 0.4147887 http://www.statcounter.com/free_hit_counter.html 0.40928197 http://www.skandinavien-fans.de/frameset.html 0.40886167 http://ff.connextra.com/Bet365/selector/click?client=Bet365&placement=Livescore_NS4default_133x200 0.39578557 http://deluxe-menu.com/ 0.3891917 http://www.entreprises.gouv.fr/zerocharges/ 0.38621464 http://www.macromedia.com/go/getflashplayer 0.38621464 http://www.nhlbi.nih.gov/whi/ 0.38621464 http://www.microsoft.com/windows/ie/ 0.38621464 http://www.quantcast.com/p-65DrxcUXjcWq6 0.38621464 http://janvanderperk.write2me.nl/ 0.38621464 ... -------------------------------------------------------------------------------- bin/nutch readdb crawl/crawldb/ -stats -------------------------------------------------------------------------------- TOTAL urls: 55730 retry 0: 55641 retry 1: 88 retry 2: 1 min score: 0.0 avg score: 0.020518823 max score: 1.713 status 1 (db_unfetched): 52824 status 2 (db_fetched): 2091 status 3 (db_gone): 229 status 4 (db_redir_temp): 374 status 5 (db_redir_perm): 212 CrawlDb statistics: done -------------------------------------------------------------------------------- bin/nutch org.apache.nutch.indexer.field.BasicFields -output crawl/fields/basicfields -segment crawl/segments/20090306093949/ -segment crawl/segments/20090306100055/ -webgraphdb crawl/webgraphdb/ bin/nutch org.apache.nutch.indexer.field.AnchorFields -basicfields crawl/fields/basicfields/ -output crawl/fields/anchorfields -webgraphdb crawl/webgraphdb/ bin/nutch org.apache.nutch.indexer.field.FieldIndexer -fields crawl/fields/basicfields/ -fields crawl/fields/anchorfields/ -output crawl/indexes |
Below is a thumbnail Class Diagram representing the Java Class ecosystem for WebGraph. You can click on the thumbnail for a much larger, downloadable picture.
