Paul René Jørgensen

I just stumbled upon an article by Werner Vogels about consistency in distributed systems. It was an eye opener and I recommend everyone interested to read it.

Eventually Consistent: “This is a specific form of weak consistency; the storage system guarantees that if no new updates are made to the object, eventually all accesses will return the last updated value. If no failures occur, the maximum size of the inconsistency window can be determined based on factors such as communication delays, the load on the system, and the number of replicas involved in the replication scheme. The most popular system that implements eventual consistency is DNS (Domain Name System). Updates to a name are distributed according to a configured pattern and in combination with time-controlled caches; eventually, all clients will see the update.”

In the same reading frenzy I also read these related pages:

• http://www.readwriteweb.com/archives/is_the_relational_database_doomed.php
• http://belaban.blogspot.com/2009/01/replcache-storing-your-data-in-cloud.html
• http://commons.apache.org/sandbox/pipeline/
• http://www.jgroups.org/demos.html
• http://www.helidb.org/

My employer Adresseavisen (local newspaper in Norway) released a Google Maps based property transfer database I’ve written for them today.

You can visit the application here: Eiendomsdatabasen