MapReduce tends to be used for massive (re)indexing. See http://search-lucene.com/?q=hadoop+mapreduce&fc_project=Solr&fc_project=Lucene for how Lucene/Solr people are using MapReduce.
For example, in a recent project we used MapReduce (streaming with jruby, actually) together with Solr (Embedded version, to be more precise) to speed up indexing of a 20 GB index that used to take a couple of hours. Now it takes 7 minutes, because it's parallelized to Nth degree. MapReduce can also be used for various Machine Learning data crunching, say for query log analysis, for content analysis, for NLP, for building of better relevance models for search, etc. etc. See http://mahout.apache.org . Otis ----Sematext :: http://sematext.com/ :: Solr - Lucene - Nutch Lucene ecosystem search :: http://search-lucene.com/ ----- Original Message ---- > From: "yuhen...@tce.edu" <yuhen...@tce.edu> > To: common-dev@hadoop.apache.org > Sent: Fri, July 30, 2010 2:23:49 AM > Subject: Re: MapReduce Usage in Search Engines > > Hi all, > I have a basic query regarding Mapreduce usage in search > engines. My queries are: > > 1.How Map-Reduce is used in search? > 2.Is Google uses Mapreduce algorithm for its search engine? Then how they > use it? Explain the architecture or flow of how google or other search > engines work and what is the part of mapreduce in it..................... > > Please Explain......... > > With Regards, > B.Yuhendar > > > ----------------------------------------- > This email was sent using TCEMail Service. > Thiagarajar College of Engineering > Madurai-625 015, India > >
