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Friday Philosophy – I killed a presentation April 1, 2010

Posted by mwidlake in Friday Philosophy, performance, statistics.
Tags: , , ,

Well, this week saw the latest Management and Infrastructure SIG. I won’t go into the SIG meeting itself just now, maybe later this weekend. If you want an opinion on it, you might like to see what Graham Oaks said.

Being Chair of the SIG I have to find presenters. Being also one of those rare people who enjoys presenting, I know I can always tap one person to present. Me. {If only I could sing, play an instrument, act, do impression, put both my ankles behind my ears(*) or anything that was of any general interest, getting an audience would be so much easier}.

I decided to tackle a topic I have tried before and which I previously did a very poor show of: “General principles on gathering database statistics”.
It is not a title to strike joy into the soul, I know, but it is really important to getting good and reliable performance out of any modern Oracle database. Even other Oracle DBA types tend to find the topic worthy but boring, but I seem to have been forced to know a lot about it and I’ve become sadly very passionate about it.

So, I tried again. I mean, how long should it take to describe the issues with database statistics and the general principles to gathering them? I took my old presentation and stripped out all code, all SQL syntax, all listing of tables and got it down to describing the process. Then I started adding the bits and pieces you need to know to get this half-right. 132 slides. Hmmmm

I tried again and took it higher level. 48 slides. I can do 48 slides in something between 45 minutes and an hour. I was ready.

I had the last presentation slot of the day. I figure if I am going to foist myself on the audience, they should have the right to leave before I start, without missing any of the good stuff. I had 3/4 of the day’s attendees still with me when I started.

I think I killed my audience. Actually, I know I killed my audience. I lost a few as the slot progressed {I kidded myself they had to get back to the office/catch a train} and I made the fatal mistake of not shutting up when I had done 45 minutes. You see, there was all this important stuff I had not mentioned yet! Thankfully, I had a friend in the second row and when I saw him lose the will to live, I stopped. I’d been at it for 70 minutes. What we really needed was the Chair to shut me up but I was the chair.

Anyway, I came away from the talk with two realisations.

  • The topic of gathering database statistics is too large to cover in one presentation session.
  • It really is very boring, even when you are passionate about it.

I think I have no choice but to make this a blog thread (as I threatened to do so about 1 month ago). But I have also promised myself to finish off SQL Audit before I start a new thread and that was 3 months ago.

So I think I am going to have to put some time into this blogging lark. It’s OK though, I seem to go on about database statistics so much that even my cat is staring to avoid me. I’ll just stop watching Star Trek and drinking wine in the evenings and switch to preparing technical blogs. And drinking wine of course.

(*) Up until 2007 I could do this. I get out more now. Despite the stats fixation


1. Doug Burns - April 2, 2010

Although I can’t promise I’ve never done it myself, there is *nothing* worse in a presentation than going way over the time allocated. It doesn’t even matter if it’s interesting. People have had their expectations set and, once you go way over it, they’re only really thinking about one thing. When will this stop?

I also tend to believe the various articles I’ve read discussing people’s utter inability to absorb much at the 1 hour point and past it …

mwidlake - April 5, 2010

You can absorb after an hour – but only if you have an over-riding stimulus (like your final exam tomorrow). Talks on stats do not class as “over-riding stimulus”, no matter how much I bounce around at the front. You are right Doug, over-running is just not good etiquette.

On the “absorbing knowledge” front, or simply keeping focus, I have never been one for “lunch is for wimps”. I think not sticking out for a break (and thus keeping usefully active all day) is the wimpy response.

Doug Burns - April 5, 2010

Ah, I agree with all of your reply, but perhaps I wasn’t specific enough here ….

You can absorb after an hour – but only if you have an over-riding stimulus (like your final exam tomorrow).

I should have been clearer that I was talking about absorbing information when you’re sitting listening to someone talk to you or, as I tend to put it at when referring to myself, talk at you. People can absorb information for much longer than an hour, but I think it’s tricky when they’re absorbing it by just listening.

mwidlake - April 5, 2010

Hi Doug,

No, no, I absolutely agree, an hour is as far as you can push “listening to someone talking”. 45 minutes is far more realistic.

We’ve both run IT courses, so we know you absolutely have to intersperse the lecturing with practicals, exercises, coffee breaks, even taking ten minutes out in the sunshine if it is a warm day and you have just hit the delegates with something challenging.

2. oakesgr - April 4, 2010

Martin, you are being way, way, way too hard on yourself. I think you were you simply trying to perform the mission impossible of the oracle presentation world, and if it wasn’t for your boundless enthusiasm and deep knowledge of the subject you would have seen a much greater exodus.

It’s also good to remember a lot of the audience weren’t DBAs and therefore might not be that interested in the minefield that is stats collecting. I think if one person came away from it having learnt something then it was worth doing. I definitely did.

3. mwidlake - April 5, 2010

Thanks Graham, it is very good of you to say so and I am glad you came away with some new knowledge. I’ll do that blog thread eventually…

4. Doug Burns - April 5, 2010

Anyway, never mind all this chat about presentation length. What was it Graham promised to present on at the next SIG?

mwidlake - April 5, 2010

He was going to decide between a Technical and a Management talk.
Technical was “How to guarantee a 50% performance increase”
Managment was “How to deal with Contractors”.
Apparently he did decide which one but could not then get either of us to shut up long enough to tell me which…
I might get him to do both.

5. oakesgr - April 6, 2010

OMG! – fragments of that conversation have just started drifting back. I’d forgotten about it completely. I am NEVER going to the pub with you two again, I get myself into all kinds of trouble.

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