Good Singapore Maths Students Would Likely Make Good Oracle DBAs (Problems) April 15, 2015Posted by Richard Foote in Oracle Indexes.
An interesting mathematics based question from a Singapore high school exam has been doing the internet rounds in the past few days. Considering it’s aimed at high school students, it’s a tricky one and obviously designed to filter out the better students, in a country with a very good reputation for churning out mathematically gifted students.
I enjoy solving problems and this one took me a few minutes to work it out. However, at the end of the process, it occurred to me that I used a similar process to how I’ve often solved performance issues with Oracle databases. In fact, this question kinda reminded me of a performance issue that I had only just recently been asked by a customer to help resolve.
One needs to clearly understand the question being asked. One also needs to focus and understand the data at hand. Then use a process of elimination to both rule out and just as importantly rule in possible answers (or root causes to performance issues). Eventually, one can then narrow down and pinpoint things down to a specific solution (or set of answers).
So for example, the database is running exceptionally slow globally at certain times, why ? So it looks like it’s because there are lots of cluster related waits at these times, why ? So it looks like it’s because writing to the redo logs is really slow at these times, why ? And so on and so on.
If you can work out the solution to this problem in a reasonably timely manner, then in all likelihood you have good problem solving skills and the makings of a good Oracle DBA. You just need to also like donuts and good whiskies 🙂
I’ve reproduced the question here, changing the names to protect the innocent.
“Bowie and Ziggy just become friends with me, and they want to know when my birthday is. I give them 10 possible dates:
May 13 May 15 May 19
June 13 June 14
July 16 July 18
August 14 August 15 August 16
I then tell Bowie and Ziggy separately the month and the day of my birthday respectively.
Bowie: I don’t know when your birthday is, but I know Ziggy does not know too.
Ziggy: At first I don’t know when your birthday is, but now I know.
Bowie: Then I also know when your birthday is.
So when is my birthday ?”
Feel free to comment on what you think the answer is but please don’t give away how you might have worked it out. For those interested (or for those that don’t check out the solution on the web first 🙂 ), I’ll explain how to get to the answer in a few days time.
Like I said, if you get it right, you should consider a career as an Oracle DBA !! And here’s a link to an excellent whisky: Sullivans Cove Whisky 🙂