Any good articles out there comparing Oracle vs SQL Server vs MySql in terms of performance?
I'd like to know things like:
Based on some real examples in order to gain a better understanding about the different RDBMS.
The question is really too broad to be answered because it all depends on what you want to do as there is no general "X is better than Y" benchmark without qualifying "at doing Z" or otherwise giving it some kind of context.
The short answer is: it really doesn't matter. Any of those will be fast enough for your needs. I can say that with 99% certainty. Even MySQL can scale to billions of rows.
That being said, they do vary. As just one example, I wrote a post about a very narrow piece of functionality: join and aggregation performance. See Oracle vs MySQL vs SQL Server: Aggregation vs Joins.
Yes, such benchmarks do exist, but they cannot be published, as Oracle's licensing prohibits publishing such things.
At least, that is the case to the best of my knowledge. I've seen a few published which do not name Oracle specifically, but instead say something like "a leading RDBMS" when they are clearly talking about Oracle, but I don't know whether that gets around it.
On the other hand, Oracle now own MySQL, so perhaps they won't care so much, or perhaps they will. Who knows.