Concurrency at Hotsos

Everyone says that the best way to go to a conference is to be a speaker. For the last 2 years I’ve been trying to go to Hotsos symposium, but I never got the time and budget for this.

So when Hotsos published a call for papers for the 2009 symposium, sending in an abstract or two with my ideas seemed to make sense. Nothing to lose, right?

I did not expect to have my abstract accepted. And now my name is up there in the speakers list, between Cary Millsap  and Chris Date. Somehow, I don’t feel like I fit in. Its been few month since I heard the news and I can still barely believe it.

Of course, now management had no choice, and I’ll get to go to HotSos and listen to terrific technical sessions from very smart people. Yay!

My  session is going to be about concurrency errors. Its a HUGE topic and it was discussed a lot in the past, so I’m working hard to find a unique and interesting angle on this, and to avoid reiterating topics that were discussed to death. My unique take on concurrency is taking classical concurrency problems from OS research, translating them to Oracle and show how they can be used to solve common issues in DB development. There will also be a fair bit of statistics and web servers thrown in because thats what I know, do and love.

I’m planning to talk a lot about testing because concurrency problems are notoriously difficult to test for. I’ll mention some statistical techniques to find concurrency problems, because this is something I didn’t see mentioned before, and I’m very happy whenever I can use my statistics education in real life.

I want to discuss lots of OS theory because so much of it applies directly to Oracle and I want everyone to benefit from the research that was done in a related field. This means talking about queuing and also about process management overheads.

I want to talk about the problems that many application servers inadvertly cause on the database side – such as allowing a user to click refresh on a large report again and again. I see these all the time.

I’ll also talk about starvation a bit, simply because I didn’t hear it discussed yet. And there is a very special case of deadlock that I’d love to talk about, if I could just get a good test case for it.

Thats quite a lot of stuff I want to talk about, and I’ll probably have to make some painfull cuts. This is after I already had to painfully cut a bunch of stuff that I decided not to talk about.

For example, deadlocks are the most well known and well researched concurrency mistake, so I’ll not spend lot of time on it. Why waste time when I can just point to Mark bobak’s presentation from HotSoS few years back (

I’ll also have to skip talking about concurrency problems on RAC. Its a fascinating topic, but its a huge one on its own. Maybe next year? I’ll also have to skip talking about undo+redo overheads caused by many concurrent updates, and latch contentions, and hot blocks… these are all fascinating and relevant aspects that I just could not fit in.

I hope I’ll manage to pull all of these ideas into a good presentation. I hope lots of people will show up and enjoy it. I’m sure HotSoS will be an amazing conference. Its in two month, but I’m already very excited about it.


17 Comments on “Concurrency at Hotsos”

  1. OCP Advisor says:

    Hi Chen:
    Wish you a very Happy New Year 2009!!
    Heartiest Congratulations on your whitepaper selection for the conference!!
    Your session would be standing room only – seats would be all full – I can bet on that!
    You are such a joy to watch and to listen!
    Best wishes,
    OCP Advisor

  2. Cary Millsap says:


    I’ll look forward to meeting you and seeing the presentation. Happy new year…


  3. daryl says:

    Please oh please, dont be another presenter that finishes his presentation on the plane on the way there .. or in the session prior to yours…

  4. Dan Norris says:

    Hi Chen,

    I’m planning to see you there too! Like you, this will be my first time attending the event (though I’ve wanted to go for many years) and I’m also presenting. Your session is on my list for sure–hope we aren’t in the same time slot or I may just cut my session and bring the one or two people that come over to yours :).


  5. Hi Chen

    Great…all the best !

    [i]>2 years I’ve been trying to go to Hosos symposium[/i]

    Ho[u]t[/u]sos 🙂

  6. prodlife says:


    LOL. This could be a problem since I was counting on attending your session. Improving our RAC architecture when I get back will be a good ROI proof for my managers. Choosing a schedule will be challenging for sure – there are so many good presentations to choose from!

  7. prodlife says:


    Yes, I’m trying to avoid that. Its no fun for anyone involved.

  8. prodlife says:


    Thanks for catching the typo. Corrected.

  9. prodlife says:


    Thanks! I’m looking forward to meeting you!

  10. prodlife says:

    OCP Advisor,

    Thanks for your kind words.
    NoCoug has its winter conference at Oracle Corp (redwood city). I’ll give a session there (and more important, Tom Kyte will give the keynote and a presentation), maybe you can attend this.

  11. Jerry Cunningham says:

    Congratulations! If your presentation is anything like your blog, I’m sure it will be great. Good luck.


  12. Patty C. says:

    Hooray – another female DBA at the Hotsos Symposium! That will make 10 of us there this year I think. LOL Congratulations! I look forward to seeing your presentation. You will love the Symposium, there is nothing else like it. I haven’t missed one yet. See you there!


  13. Bob Watkins says:

    It’s also pretty cool to attend conferences as press. As a freelance writer, I’ve been able to attend Oracle OpenWorld a couple of times with a press credential. The conference fee is waived, and you have access to Oracle executives in daily pressroom briefings. The downside, though, is that nobody wants to talk to you when you have a “Press” ribbon dangling from your conference badge! I tried covering it up with my “I’m an OCP” button.

    Dang, now I have to try and get to Hotsos! It’s embarassing that I don’t go, because I live in the Dallas area.

  14. a says:

    In a special effort to appeal to women, organizers of a gaming convention this past weekend handed out buttons that had a picture of Rosie the Riveter, with the message “i pwn n00bz.”

    Maybe “hotsos hottie”? 🙂

  15. Robert Klemme says:

    Will you cover the “shared server” deadlock? Tom Kyte mentions it in “Effective Oracle by Design”. This is not a “regular” deadlock but a deadlock nevertheless. IIRC it occurs when one session obtains a lock, goes off the shared server process and there are other sessions executing in their respective shared server processes waiting for the lock to be released. Now if because of the waiting no shared server is released to do the commit (or rollback) work of the first session you’re out of lock – err – luck.


  16. prodlife says:

    Hi Robert,

    Its a good question. On one hand, this is one of the most exciting examples of deadlock. Especially since Oracle does not detect it, which make it much harder to resolve (probably involves killing more than one session).

    On the other hand, I have zero practical experience with shared servers, and I don’t like talking about things I don’t actually do.

    So, the answer is “I won’t talk about it, but I wish I did”.

    In any case, there is more than enough examples to cover. The hard part is squeezing everything into one hour…

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