Friday Dec 05, 2008

MySQL University for up to 100 attendees

Yesterday (December 4th), Sergey Petrunia gave a presentation on what's new in MySQL Optimizer. Unfortunately, the slides didn't show up in the Dimdim presentation area, which also means that the recorded session only has Sergey's voice but not the slides. (I've filed a bug in Dimdim's issue tracker.) However, Sergey kept referring to slide numbers in his talk, so it should be fairly easy (just not as convenient as usual) to follow his recorded presentation.

The slides, together with links to the recording and the chat transcript, can be found on the MySQL University session page.

Next week (Thursday, December 11th), we'll use our brand new commercial Dimdim license to run the session. This includes a new session address / Dimdim URL:

You can bookmark this one; it will remain valid for all future sessions. Remember, though, that the meeting room will open only 15 minutes before sessions start.

Our new commercial license is for 100 seats, so everybody should be able to join future sessions. (For Sergey's session, we had between 15 and 20 participants. We were still using my free Dimdim account for that session, which limits the number of attendees to 20. I suspect some people couldn't join in. Sorry for that.)

Next week's session will be about the Random Query Generator, a tool that creates random queries that can be sent to the MySQL server. This MySQL University session will start at 14:00 UTC / 8am CST (Central) / 9am EST (Eastern) / 14:00 GMT / 15:00 CET / 17:00 MDT (Moscow).

 Date Time
Topic Presenter
December 11 14:00 UTC / 8am CST (Central) / 9am EST (Eastern) / 14:00 GMT / 15:00 CET / 17:00 MDT (Moscow) Random Query
Philip Stoev
December 18 14:00 UTC / 8am CST (Central) / 9am EST (Eastern) / 14:00 GMT / 15:00 CET / 17:00 MDT (Moscow) Using DTrace with MySQL
MC Brown

In January, we'll likely continue with a set of sessions on performance and scalabilty – straight from the Sun QA labs. Find the tentative 2009 schedule on the MySQL University home page.

Wednesday Nov 26, 2008

No Webex With Firefox 3 on Linux

Admittedly, I'm not a big fan of Webex (in case you don't know what that is (lucky you!), it's a conferencing system), which might explain why Webex seems to hate me sometimes, but today Webex made me laugh. Or maybe cry, I'm not sure after having wasted more than an hour trying to set up Webex' Meeting Center on another computer. (I'm not sure if it's Meeting Center or rather Meeting Manager. Webex doesn't seem to be sure either.)

I'm exclusively running Linux on my computers (currently SuSE 10.3 and 11.0), and so I'm used to web sites not working properly, requiring some weird browser plugin that's hard or impossible to find, or requiring me to tune my browser settings. I'm mostly on Firefox (versions 2 and 3), but sometimes I use other browsers. Today, I had to use another browser.

The trouble started when I tried to set up Webex' Meeting Center, which is the requirement for being able to join a Webex meeting. As you can see in the screen shot, Webex claimed that Java wasn't enabled in my browser. The download URL provided in the error message turned out not to be helpful – it took me to a page with links for Windows and Mac OS X. But I'm on Linux. (This would be easy to find out for the Webex guys, since I'm not hiding or masking my user agent settings. But I agree that it's even easier to ignore.)

I double-checked, and of course Java was enabled in Firefox. This is my first 64-bit computer with a 64-bit SuSE 11.0, though, so I thought this might be the cause of the problem. I googled a lot, but couldn't find anything useful.

Out of curiosity, I fired up Microsoft Internet Explorer 7 (thanks to CrossOver for helping me install all those Windows applications on Linux!), copied the Meeting Manager setup URL from Firefox, and pressed Enter. And voilà – Meeting Manager was set up within a few seconds.

Come on – do you really want me to use Internet Explorer on Linux? This is silly.

After some more clicking through the Webex web site, I found this page, which seems to indicate that Webex doesn't support Firefox 3 on Linux:

Then again, there's another page that contradicts the previous page (or maybe I'm not understanding it, and it really says that Firefox is supported only by two thirds):

Anyway, on this particular computer (which is in my living room), I'll probably use Internet Explorer whenever I'm forced to use Webex. Joy.

Whenever I can choose, I'll use Dimdim over Webex, though. Dimdim does the same things as Webex, only better. Much better, I would say (see my blog post on using Dimdim for MySQL University). And it requires just a Flash plugin. My Firefox browsers, 64-bit or 32-bit, version 2 or 3, have a Flash plugin that works for Dimdim. From a loyalty standpoint (I work for Sun Microsystems), I'd prefer a conferencing system that uses Java over one that uses Flash, but I hate it when web sites seem to give me a message like "we're using Java because it's platform-independent, but you'd better use Windows or Mac to stay out of trouble". I take comfort in the fact that Dimdim uses MySQL, though, and says so openly and visibly.

I have no experience how Dimdim scales, though. So far, I've used it for a maximum of 20 participants. (I've attended Webex sessions with well over 100 participants.) I'll keep you updated when I find out.

Friday Oct 24, 2008

MySQL University Using Dimdim

After a series of tests, we've just conducted the first MySQL University session using a new conferencing system, Dimdim, and I thought I'd let you know how it went.

MySQL University is an educational program for engineers from Sun/MySQL and the MySQL community, Dimdim is the new conferencing system that we hope will be able to replace our old presentation system, and "we" isn't plurale majestatis but rather refers to the guys running the MySQL University program, the Sun Database Group documentation team.

I started the Dimdim session fifteen minutes before the hour, and when the two presenters arrived we did a sound check. Petr and David connected from Sun offices in Prague, Czechia, and California, respectively, and I was on a DSL line in my home office in Berlin, Germany. Sound quality was excellent, as if Petr and David were standing next to me. Other attendees confirmed that sound was great for them, too, and also reliable (very few drop-outs). Speaking of sound: Dimdim doesn't require you to use a telephone for the voice channel (although you could) – it's VoIP, straight over the Internet and out of your browser's Flash plugin. It's VoIP for presenters, too – all you have to do is allow Flash to access your microphone, and your voice can be heard. If you have a camera attached you could also video-stream your face, but we haven't tried this.

David sharing his desktop to demonstrate using MySQL with NetBeans

What worries me is that my own voice sounded like I was a chipmunk (or, as David put it, as if I had inhalated helium). The day before, in one of the many test sessions I ran, my voice was okay, but then I was sitting in the same room where my wireless access point is located. This time, I was sitting in a room next door, in an effort to reduce sounds from my children playing. Looks like connection quality is extremely important for Dimdim's VoIP, at least on the "active" side – just for listening it didn't make a difference when I was on a signal-wise low-quality wifi (at other test sessions we did). I'm not sure how this will work out for presenters who are on less-than-optimal Internet connections.

There were twelve people in this session, including presenters and host. I asked them where they were from, and it turned out they were from all over Europe and North America (see screen shot). One participant was from Japan. Since no one was reporting anything but minor problems, this indicates that Dimdim works well in many places on this planet.

Petr and David showed some slides. Currently you can share PowerPoint and PDF. It's quick for both presenters and audience, and the user interface for presenters is functional and slick. They also shared their desktops to demo NetBeans – desktop sharing requires a browser plugin that's available only for Windows and Mac OS X, but the Dimdim folks claim that they're working on a Linux version, too. Desktop sharing is kind of slow, but as long as presenters keep in mind that redrawing on the receiving end takes some time I think it's good enough. For presenters, it's a bit of a challenge to arrange their windows in a way that they can still see the Dimdim chat sidebar (so they can see questions), and also they should use only a small part of their screen because otherwise the audience will have to scroll in the shared-desktop area in order to see everything. From what I know Petr and David used a resolution of 1280x1024, and they demoed in the upper left two thirds of their screens. I could see everything they did in my full-screen browser window without having to scroll.

Now for some bad news:

  • "Active" voice stopped working for me after a few minutes. I noticed when Petr rudely ignored and interrupted my talking, but it turned out that Flash had stopped capturing my voice. Being the host, I couldn't just restart my browser, or the meeting would have ended surprisingly for everyone. (I still have to find out if that's really the case or if I'm just paranoid.)
  • Recording has severe limitations. For one thing, not everything is recorded. According to Dimdim, audio and video of the presenter is recorded, and so is the chat log. The shared area is recorded only for presentation slides. Shared-desktop sessions and whiteboard scribblings aren't recorded. What's worse, you can only record one presenter. Had I recorded Petr, the recording would have stopped after assigning the presenter status to David. Restarting recording would have resulted in Petr's recording being overwritten by David's. Lame. So I resorted to just recording David's part of the presentation. After the session had ended, I received an email with a link to the chat log. And that was it. No link to the voice recording. Maybe the session wasn't ended properly (see next bullet item) and thus some trigger on Dimdim's side didn't fire, I don't know. I've reported the problem to the Dimdim folks.
  • Firefox froze after I clicked "end meeting". This has happened before, and I suspect it's due to Flash doing bad things to my browser. Nothing major, though, since it only happens when the session is over, anyway, and thanks to Firefox' excellent crash recovery it's back with its previously opened tabs within seconds.
  • I'm on Linux (for this particular session, on 32-bit Linux). Multimedia applications often favor Mac OS X and Windows to an extent that Linux users can only hope that things will work at all for them. Not so Dimdim – they've done a remarkably good job for Linux users. Still, there's that feeling that things are less smooth and reliable on Linux, but I guess the Dimdim folks can only do so much about it, since most of the issues will likely have to be resolved by the makers of Flash.
To conclude, I'm quite happy with how this session went. I'm curious to see if things will work out similarly well for other presenters, particularly if they're on Linux. Time will tell.


mysqlf is a common typo on the #docs IRC channel of the MySQL documentation team. It shows a high (some might say, dangerous) degree of identification with MySQL. Trying to pronounce it will probably result in tongue injuries.


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