Apache Con – last day

2010-11-27 23:23
Day three of Apache Con started with interesting talks on Tomcat 7, including an introduction to the new features of that release. Those include better memory leak prevention and detection capabilities – the implementation of these capabilities have lead to the discovery of various leaks that appear under more or less weird circumstances in famous open source libraries and the JVM itself. But also better management and reporting facilities are part of the new release.

As I started the third day over at the Tomcat track, unfortunately I missed the Tika and Nutch presentations by Chris Mattman – so happy, that at least the slides were published online: $LINK. The development of nutch was especially interesting for me as that was the first Apache project I got involved with back in 2004. Nutch started out as a project with the goal of providing an open source alternative internet-scale search engine. Based on Lucene as a indexer kernel, it also providing crawling, content extraction and link analysis.

Focussed on building an internet scale search engine the need for a distributed processing environment quickly became apparent. Initial implementations of a nutch distributed file system and a map reduce engine lead to the creation of the Apache Hadoop project.

In recent years it was comparably quiet around nutch. Besides Hadoop also content extraction was factored out of the project into Apache Tika. At the moment development is getting more momentum again. Future developments are supposed to be focussed on building an efficient crawling engine. As storage backend the project wants to leverage Apache HBase, for content extraction Tika is to be used, as indexing backend Solr.

I loved the presentation by Geoffrey Young on how they used Solr to replace their old MySQL search based system for better performance and more features at Ticketmaster. Indexing documents representing music CDs presents some special challenges when it comes to domain modeling: There are bands with names like “!!!”. In addition users are very likely to misspell certain artists names. In contrast to large search providers like Google these businesses usually have neither human resources nor enough log data to provide comparable coverage e.g. when implementing spell-checking. A very promising and agile approach taking instead was to parse log files for most common failing queries and from that learn more about features needed by users: There were many queries including geo information coming from users looking for an event at one specific location. As a result geo information was added to the index leading to happier users.

Sesat - moving from FAST to Solr

2009-12-01 22:07
The article was first published on Sesat Weblog. As the whole site went down several days ago, I retrieved the content from the Google cache and posted it here for perservation.

Update: Original site is up again.

Moving from Fast to Solr

2009-11-19 20:34
Sesat has published a nice in-depth report on why to move from Fast to Solr. The article also includes a description of the steps taken to move over as well as several statistics:


On a related topic, the following article details, where Apple is using Lucene/Solr to power it's search. Spoiler: Look at Spotlight, their desktop search, as well as on the iTunes search with about 800 QPS.

Update: As the site above could not be reached for quite some time, you should either look into the Google Cache version.