Share what you know

Learn what you don’t

Neo4j for Ruby on Rails

“Neo4j is a graph database. It is an embedded, disk-based, fully transactional Java persistence engine that stores data structured in graphs rather than in tables. A graph (mathematical lingo for a network) is a flexible data structure that allows a more agile and rapid style of development.”

Neo4j allows you to map objects to nodes and relations, that is a more natural fit than mapping them to relational tables. Modeling with elements of a graph is substantially faster for semi­structured data (Recall that semi­structured data is data that has few mandatory but many optional attributes).

Neo4j is a powerful graph database/engine that every rails developer should know.

It turns out that I got involved with neo4j evluating a graph-databse for several graph-intensive operations we had to perform over an 8million vertices/100million edges graph. I decided to give a talk in the Spanish Rails Confenrence 2010 about Neo4j and graph-databases.

The title of my talk was Neo4j for Ruby on Rails

I did cover:

  • An overview of the technology of graph databases (particularly neo4j database)
  • How to model your world with nodes, relationships and properties.
  • How to use neo4j with jruby, neo4j-rails for ruby on rails and neo4j-rest JSON REST API
  • Implement simple graph recommender (using traversals), and compare it to a global recommender (using the whole graph at once)

Neo4j and Rails - Conferencia Rails 2010 from pablete on Vimeo.

Here are some photos (thanks @valakirka):

"Pablo Delgado Neo4j: Beginning"

"Pablo Delgado Neo4j: Edges"

"Pablo Delgado Neo4j"

Euruko 2009 is over

Euruko 2009 conference in Barcelona, Spain was excelent! The venue was really good. Everything was very well organized by the great people of the SRUG.

My favorite talks were:

Here are some photos I took:

"Pablo Delgado"

"Joshua Sierles and Xavi Noria"

"Euruko 2009 is over"

"Spanish Ruby User Group"

The rest of the photos can be seen in flickr, just search for the tag #euruko2009

Next Euruko will take place in Krakow, Poland on the 22nd and 23rd of May, 2010.

Talking at Conferencia Rails. Madrid 2007


I escaped London for a few days to go to Conferencia Rails 2007 in Madrid. There I gave a talk about much ranted Rails Scalability.

The title of the talk in spanish was “Escalabilidad y las cosas de las que nadie se atrevio a hablar”.

Summary of the talk:

  • Architecture and typical Rails deployment configurations.
  • Use of Nginx as a static assets server.
  • Mongrel and Evented Mongrel.
  • Multithreaded image Uploads with mongrel and/or merb (instead of attatchment_fu)
  • Activerecord optimizations (hacks, active_record_context plugin)
  • Caches, pasive expirations. Cache observing daemons.
  • Configuration and monitoring of a production Server. (monit, munin tools)

Here is the video of the talk, and of course, the slides.

The talk went fine, I have had so much fun speaking spanish again.

Here are some photos:

"Conferencia Rails 2007"

"Merb framework"

"Rails stack"