2008: Schema Evolution in Wikipedia: toward a Web Information System Benchmark

 
Evolving the database that is at the core of an Information System represents a difficult maintenance problem 
that has only been studied in the framework of traditional information systems. However, the problem is likely 
to be even more severe in web information systems, where open-source software is often developed through 
the contributions and collaboration of many groups and individuals. Therefore, in this paper, we present an in- 
depth analysis of the evolution history of the Wikipedia database and its schema; Wikipedia is the best-known 
example of a large family of web information systems built using the open-source MediaWiki software. Our 
study is based on: (i) a set of Schema Modification Operators that provide a simple conceptual representation 
for complex schema changes, and (ii) simple software tools to automate the analysis. This framework allowed 
us to dissect and analyze the 4.5 years of Wikipedia history, which was short in time, but intense in terms of 
growth and evolution. Beyond confirming the initial hunch about the severity of the problem, our analysis 
suggests the need for developing better methods and tools to support graceful schema evolution. Therefore, 
we briefly discuss documentation and automation support systems for database evolution, and suggest that the 
Wikipedia case study can provide the kernel of a benchmark for testing and improving such systems. 
 
To appear ICEIS 2008
 
Here you can find a copy of the paper.