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April 2012

The proof is out there

I’d like to thank Jonathan Lewis for taking up my challenge and writing up a proof that there is indeed a formula that solves Cary Millsap‘s string problem for not just circles, but for any regular polygon.

Like Jonathan, I found the problem intriguing, and “wasted” a few hours on a Saturday afternoon discovering the formula.

This blog entry isn’t about the formula or proof — it’s rather about the process I used to discover it.

You see, I didn’t know that such a formula actually existed before I set out — but I was convinced that there might be. After all, it would be neat if there was one, wouldn’t it?

Thanks for attending the webinar!

Thanks to everyone who attended my two Embarcadero sponsored webinar sessions. I promised to make the slides and some scripts demonstrated in the slides available so here they are:

Slide deck (pdf format)
Scripts (zip format)

Keep an eye out for more webinars I'll be conducting in the coming months!


The post reminded me of my own fail happened several months ago.

Exadata experience, what does that actually mean?

As an active member of the Oracle user community I really enjoy talking to delegates at user conferences and user group meetings. As such I was very lucky having had the opportunity to attend two of them recently. I have written about the OUGN spring conference in the post before this, and I also enjoyed the AIM meeting earlier in March.

One of the subjects that always seems to come up is Exadata. Many, many DBAs want to have Exadata experience, and if only to tick a box. Now Exadata means a significant investment, in other words not every company on the planet will have one. On the other hand it’s reasonably complex to administer, therefore recruiters and other HR personal are very interested in DBAs with “Exadata experience”. Now, the reason of this blog post is an open question to the readers: what do you consider as Exadata experience?

Planned Website Downtime…

The recent server switch within Fasthosts has not solved the availability issues with my website. It was down for 30 minutes again yesterday. Since the initial (accidental) server move in December the availability of the site has been terrible. What’s worse, Fasthosts seem incapable of giving me any information as to why. It’s on a shared hosting platform, so there isn’t much I can do to diagnose the issue myself.

ACED Annual Self Evaluation…

If filled out my ACE Director Annual Self Evaluation today. Between 1st June 2011 and now, which is about 10 months, I did the following:

  • Over 40 new website articles (close to 1 a week). This does not include rewrites of existing articles, some of which I could legitimately claim as new articles, since they bear* little resemblance to the originals.
  • Over 150 new blog posts (every other day, give or take).
  • Over 3500 new forum posts (about 11 a day).
  • 9 conference events.
  • A random assortment of Twitter, G+, Facebook, LinkedIn and email messages.

It’s quite scary when you list it like that. :)




Recently I used the COMMIT_WAIT and COMMIT_LOGGING parameters for solving (or, better, working around) a problem I faced while optimizing a specific task for one of my customers. Since it was the first time I used them in a production system, I thought to write this post not only to shortly explain the purpose of the these two parameters, but also to show a case where it is sensible to use them.

The purpose of the two parameters is the following:


Philosophy 16

I couldn’t help laughing when I saw this.

RMAN duplicate and read-only tablespaces

This one is to be filed under the “little things I didn’t really know until now” section: RMAN duplicate. Be honest to yourself: would you have known the answer to this question: what happens to tablespaces which are read-only on the source during an RMAN duplication (not for standby)?

Some background

I have started my career as a DBA on Oracle, and at the time not everyone fully embraced RMAN. OK, RMAN made it really hard at the time to fall in love with it. So when we “cloned” our production database to development, the following steps were followed:

Another one (conference) bites the dust…

Unfortunately I’ve just had to pull out of the Austrian Oracle User Group conference in Vienna in June. It’s a one day conference and only one of my papers was selected. The ACED travel support requires that at least two* papers are selected before you can apply for approval, so that knocks me out of the running. Sorry for any inconvenience to the organizers. On the positive side, another slot has opened up in the schedule for someone else to present. :)

As a note to other ACEDs, make sure conference organizers are fully aware of the conditional nature of your application. I always try to remind people that I can only come if I get travel approval, but in this case that message got lost somewhere down the chain.