Wikipedia Profiler: a great in-sight in the Wikipedia DB backend

Wikipedia is one of the biggest DB-based website around, with over 700Gb of data.

Both data and schema are available: (data) (schema)

moreover the result of a profiler running on the Wikipedia installation of MediaWiki is made available at:

this means having workload and queries of the actual Wikipedia. I spent in the last months quite a lot of time working on this dataset. Soon i will post the result of my analysis, which has been accepted for publication at ICEIS 2008.



Klein Four: geekest math song… love them

This guys are just amazing… math majors at Northwestern in Chicago… they sing “a capella” the geekest song ever…


 For the sake of understanding better… follow the lyrics.. and visit their website: 

Finite Simple Group (of order two)
A Klein Four original by Matt Salomone
The path of love is never smooth
But mine’s continuous for you
You’re the upper bound in the chains of my heart
You’re my Axiom of Choice, you know it’s true
But lately our relation’s not so well-defined
And I just can’t function without you
I’ll prove my proposition and I’m sure you’ll find
We’re a finite simple group of order two
I’m losing my identity
I’m getting tensor every day
And without loss of generality
I will assume that you feel the same way
Since every time I see you, you just quotient out
The faithful image that I map into
But when we’re one-to-one you’ll see what I’m about
‘Cause we’re a finite simple group of order two
Our equivalence was stable,
A principal love bundle sitting deep inside
But then you drove a wedge between our two-forms
Now everything is so complexified
When we first met, we simply connected
My heart was open but too dense
Our system was already directed
To have a finite limit, in some sense
I’m living in the kernel of a rank-one map
From my domain, its image looks so blue,
‘Cause all I see are zeroes, it’s a cruel trap
But we’re a finite simple group of order two
I’m not the smoothest operator in my class,
But we’re a mirror pair, me and you,
So let’s apply forgetful functors to the past
And be a finite simple group, a finite simple group,
Let’s be a finite simple group of order two
(Oughter: “Why not three?”)
I’ve proved my proposition now, as you can see,
So let’s both be associative and free
And by corollary, this shows you and I to be

Purely inseparable. Q. E. D. 


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.  

iPhone: stacked to mute (a new solution)

This is a known issues… it might happen to you that the iPhone stop speaking to you.

In my case in particular there was no earphone, no speaker, no sounds in the normal call… basically a completely mute phone..

i tried all the “conventional” ways of inserting multiple times the earphones, cleaning the hole with Windex etc… no luck…

So i simply tapp on:

“Settings>General>Reset>Reset All Settings” 

And automagically the iPhone went back to life and start speaking to me again.. speaker, phone speaker and earphones work like a charm