Hotsos 2010 - Day 4

First up was Cary Millsap's - Lessons Learned, Version 2010.03 As Cary pointed out, they always try to put the best speakers in the toughest slots - 8:30 in the morning post-party. I think local guys are slightly more reliable too because they might have actually gone home the night before! He started with a quick Hangover Survey (me - check!) and then pressed on talking about how we test system performance.

He showed a video of Boeing stress-testing the wing of the 787 and, as he pointed out, aircraft manufacturers really know how to stress-test! (Of course whether that reassures you as it does me, or makes you wish no-one would talk about wings disintegrating, as it probably would Mads, is personal.) They showed Boeing test equpiment which is complicated, expensive and non-revenue generating. Those tests are expensive but when people's lives are on the line, what choice is there? Boeing knows that it has to test the analytic models used in the design. He spent a lot of time talking about good test design. A few thoughts that stood out to me ...

- Some stress tests are a waste of time. Will the Boeing 787 land on the moon? If this test fails, what has it proven? If it passes, then it's awesome but it would be a very expensive way to prove it can cope with commercial flights in Earth's atmosphere.

- Why test for more than you will see in Production? Because you don't really know for sure what you'll see in Production.

- At some point, but I can't remember the context, he used a Scottish phrase that he'd heard Billy Connolly shout (although the Big Yin was only fully credited later in the day) ...

    "There's no such thing as bad weather, just the wrong clothes"

... looked over at me and said - "I'd love to hear you say that, with the proper accent". I declined politely.

- Most people try to prove only that their systems will work.

- Most tests of systems that are destined to fail never proved it in advance.

- Test to destruction

    a) Test
    b) Until the system melts
    c) Decide whether your real requirements are likely to be lower or higher than melting point.

There was a small amount of time for questions and once it looked like they were done, I granted Cary's wish (never thought I'd say that), stuck my hand up and repeated The Big Yin's words. It was only after the laughter had stopped that I realised I might have ruined his big closing, but I think he was ok about it

Next was Tanel Poder talking about LGWR, log file sync waits and COMMIT performance and shock, horror, I was actually going to say that this was one of the least rewarding sessions of the week for me. What?!? Tanel? But he's, like, an Oracle God! LOL But there were reasons

- I realise that I know a *lot* about how log file sync and log file parallel write work, how they relate to each other and some of the problems they might help you identify. Because it's a subject I'm *so* familiar with, I didn't learn much.

- His main demo didn't quite show what he wanted it to because it didn't run multiple sessions but, frankly, I'm in no position to talk about demos this week!

By the end, the presentation turned out ok, not least because there was another unexpected appearance from Bob Sneed to talk about the I/O components involved in  redo log management including a suggestion that LGWR be put into a higher scheduling class (but not Real Time!) Updated later - make sure you read Bob and Kevin's comments below. I'll try to find a link to his slides and let you take a look yourself.

I loved Tanel's Big Log File Sync Tuning Secret, though ...

    COMMIT LESS!

It was particularly relevant to me because I had a Big Log File Sync Tuning Secret as the closing moment of my own presentation. The problem was I couldn't use it after the demos went wrong!

    USE ASYNCHRONOUS COMMITS

But, in my case, that was supposed to be funny, too.

I ran off to try and use the free breakfast voucher that Marco had given me but I was just too late. No food again, then Well, I had a couple of slices of cold meat at lunchtime, but mainly to catch up with Alex G before he had to present and then head back to Ottawa. I managed to skip one session at this stage but, after a quick call home, I decided to go along to Alex's RAC Connection Management presentation after all (a little late). Although I have seen some of this stuff before, I always enjoy watching Alex's demos and was particularly impressed by the fact that he'd managed to write his own RAC connection load balancer! I was waiting for the applause in the room but either people didn't quite get it or there was just a lack of energy post-lunch on the last day. I suspect the latter.

Of course, once I'd said goodbye to Alex properly (don't see him nearly enough), I was a little late for whichever session was going to be my final one of the conference and I was hopelessly torn between Kyle Hailey's modern SQL performance tools presentation (Kyle's done a lot of cool work in the area of Oracle Performance Visualisation) and Chris Antognini's Diagnosing Parallel Executions Performance. In the end I plumped for the latter because I thought it was going to be like something I'd unsuccessfully attempted a couple of years ago and I wanted to see if Chris had a different angle on it and had been more successful. In the end, I probably made the wrong choice because although Chris' presentation was great, it was really all stuff I already knew. Definitely my bad call, though. Hopefully I'll get a chance to catch up with Kyle's presentation at some point in the future too!

After that there was just the usual short farewell and thanks from Gary Goodman of Hotsos. Although the thanks were appreciated, I'm glad they were spread around everybody because the attendees are one of the things that make this conference great and Becky and Rhonda did their usual sterling job of organising everything.

Then it was time for some Fajitas with a few friends (actually, a whopping great number of friends who practically filled the Mexican restaurant!) and a few very sedate beers. (We are old men (and women) now and the night before was a big one!) While we were waiting to go to the Mexican, I had one great surprise left - Alex's flights weren't going to get him home, so he came back from the airport and had to check in overnight! At least I got a chance to talk to him properly when I wasn't hopelessly drunk and didn't try to seduce him this time.

Now I need to stop blogging and get back to listening to Tanel's Training Day (good stuff, too, but more about that later)