RDF in a...database?

This is has many similiarities in a recent conversion about the relational model and RDF, comes "Relational databases for storing and querying RDF":

Our work in this area, "Scalable Semantic Web Data Management Using Vertical Partitioning," appeared in the VLDB Conference in Vienna in September. It showed that using a column-oriented database, along with this property representation, allows us to overcome the overhead of representing NULLs, while providing two orders of magnitude better performance than the naive triples representation. This is particularly true when processing queries that must access many triples during execution (e.g., computing the number of books grouped by subject area or institution.) Of course, there is a fair amount of subtlety to getting good performance out of such a representation. Have a look at our conference paper for the details!

This paper and others was mentioned previously. This view, of property tables in column databases, is very similar to untyped relations.

Column Databases Reach Slashdot

In a typically incorrect charactization of the issue Slashdot is covering column databases: Relational database pioneer says technology is obsolete via Are Relational Databases Obsolete?. A better way to explain it, is that column databases are designed to get around the current problems with modern computer architectures such as latency in memory and hard disks as well as achieving better CPU utilization (typically databases have very little parallelism).

While it's early days yet, column databases storing something like RDF may get faster than row-oriented SQL databases. I posted about column databases storing RDF previously.

"Vertica beats all row stores on the planet -- typically by a factor of 50," he wrote. "The only engines that come closer are other column stores, which Vertica typically beats by around a factor of 10."

And from the cited blog:

In addition, it provides built-in features appropriate to the needs of 2007 customers. These include:

o Linear scalability over a shared-nothing hardware grid
o Automatic high availability
o Automatic use of materialized views
o "No knobs" -- minimum DBA requirements

Seeing as though I've just been looking into this here are a few references:

• The End of an Architectural Era (It’s Time for a Complete Rewrite) One of the links from my previous post written by Michael Stonebraker and others. It provides a deeper explanation of column databases than in the above articles.


• Decomposition Storage Model the paper that started it all (from 1985). Section 2.5 is especially relevant as it mentions how to store directed graphs and parent-child relationships.


• Database Architecture Optimized for the New Bottleneck: Memory Access


• Monet: A Next-generation DBMS Kernel for Query-intensive Applications

Update: InfoQ and artima have also picked up on the story.
Update 2: While I'm normally pretty skeptical about most things, column databases have had their own fair share of problems in the past.

Everything You Know is Wrong

• OWL can be, as the French would say, databasesque. Using OWL to implement database like integrity constraints.


• It's time to throw away your database (a paper describing the advantages of column databases) and replace it with something more flexible and scalable (using C-Store to store RDF). And column databases mean no NULLs. The problem isn't that your data is normalized it's that it's not normalized enough (also mentioned here).


• Following a question that I had earlier this year about where is the good code to learn from, I've read about 3/4 of Beautiful Code. And while I have a hard time finding C/C++ code beautiful it certainly covers some good examples of code and the process behind writing it (including Beautiful Tests, Beautiful Concurrency and MapReduce).


• Latency Moore's curse.


• Nova links to why what you thought about genes is wrong (I've actually heard this before but hadn't come across any articles).


• Scaling laws in Biology. Humans run on 100 watts or used to. Now we have cars etc. our power requirements are now 11,000 watts (making us the biggest creatures that have ever lived). And the magical number: 4.


• The Enemies of Reason is now on Google Video.