Design, implementation and experiment of a YeSQL Web Crawler
  We describe a novel, "focusable", scalable, distributed web crawler based on GNU/Linux and PostgreSQL that we designed to be easily extendible and which we have released under a GNU public licence. We also report a first use case related to an analysis of Twitter's streams about the french 2012 presidential elections and the URL's it contains. 
Pierre Joulin, Romain Deveaud, Eric SanJuan-Ibekwe, Jean-Marc   Francony, Fran\c{c}oise Para
cs.IR