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Showing posts from May, 2013

This Blog Has Moved!

Right, so yes, five years ago I moved to github pages, and never bothered to redirect any of these pages there. Now I've moved on from there, and... Finally I am using my real domain, trishagee.com . My blog is now at trishagee.com/blog .  See you there!
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Adjusting to Working Remotely

One of the most obvious differences I faced when I moved from LMAX to 10gen were the working conditions. I don't mean like being deep underground in some dangerous situation vs being pampered by beautiful slave boys and girls. What I mean is that the working practices at one company necessitated being in the office for core hours, and at the other flexible hours and remote-working are practically mandatory. At at LMAX we pair-programmed most days, and that meant that being co-located: being in the same office, at the same computer, was pretty important. We could work from home when needed, but pairing is pretty tricky when you’re in a different room. The drivers' team at 10gen, on the other hand, is a very distributed team. Sure, I'm based in London, and we have an office here. But my main Java "pair" is in Boston, working from his home office. The other driver developers are distributed around the New York, Palo Alto and London offices, with m...
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Be an Ambassador!

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You know how I keep banging on about attracting different types of people into programming?  You know how we say we need to get them young? Typical Mathematician? A little while back I decided to put my money where my mouth was, so I signed up to be a STEM Ambassador .  STEMNET is an organisation that aims to inspire children to go into Science, Technology, Engineering and Maths careers, and it does this by creating a network of mentors (people like you and me) and schools.  So schools can publicise the sorts of events they're running, and find mentors in an appropriate field for this event. I was a STEM Ambassador years ago, when I worked at Ford STEMNET came there looking for people like the graduates to come and talk to kids - STEMNET likes to have a large proportion of their ambassadors close(ish) to the age of the kids, so they grab graduates working in large organisations and apprentices.  Those just starting out in their careers often think they don't ...
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My Summary of GeeCON, Krakow

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Last week I was in Krakow, Poland for GeeCON .  Which was excellent!  I find it really interesting that conferences all have their own personalities, that they are not all the same. GeeCON had its own distinct personality.  If you're a Java/JVM person based in Poland, I would highly recommend it - more than 90% of the attendees were Polish (probably the remainder were largely speakers) so this conference is very much for you.  The quality of the speakers was really good too, I learnt a lot off many of them. From a speaker's point of view, there were some cultural things which took a bit of getting used to.  One of the good things was that the audience was very keen on asking questions, they were much more interactive than a typical London audience (for example).  However, I'm accustomed to quite short questions, and I found that the audience liked to give a lot of detail in their questions and frequently ask more than one at once - this meant that all...
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How are you using MongoDB with Java?

So, like one of my presentations, I have a question for you.  Actually, I have more than one question for you.  I'm not going to bother with survey monkey or whatever, I want to share the answers so please, answers in the comments: Are you using the Java driver for MongoDB in your application? Are you using the Java driver directly, or are you using a third party library like Morphia, Spring Data, the Scala driver, your own abstraction layer, etc? If you're using a third party library, why did you choose that over using the Java driver directly? If you're using the Java driver directly, what do you like about it?  If you're using the Java driver directly, are there any areas that give you pain?  Areas for improvement? Which version of Java are you using? Feel free to leave additional information if you have it.  And this is a public blog, so if you're really mean I'll just delete your comment.  So there.
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Good overview of the NoSQL hype for Real Developers

Last Tuesday I went to a London Java Community talk which promised to debunk the hype around NoSQL.  Whether you're already bought into a NoSQL technology, or you're just wondering what all the noise is about, it's worth an hour out of your day to see Akmal Chaudhri's comprehensive summary of the technologies out there. Skillsmatter recorded the whole thing, as usual, so you can watch the presentation for yourself .  I promise neither I nor anyone else from 10gen paid him to mention MongoDB so much.
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2013 is looking a lot busier than I planned...

So, despite promising myself that I would only do one event a month for the rest of this year, looks like I'm going to be a bit busier than that. In case you're wondering what I'm up to (or, even better, hoping to see me talk or meet me), here are my confirmed engagements: 15-17 May - GeeCon , Poland 18-20 June - GOTO Amsterdam - whole day tutorial on the new (unfinished) MongoDB Java driver. 24th June - STAC Summit , London - something MongoDB-shaped (i.e. not Java-specific) 27th June - Technology Transformation Network , London 1-5th July - In Dublin, hoping to talk to a MUG or JUG while I'm there. 22-25th July - JavaOne Shanghai (CON1148). So excited to go to China! August - Looks like I'm going to be in Spain a couple of times (Madrid/Seville). 11-12th Sept - Love to go to JavaZone, Oslo.  We'll see. 22-26 Sept - JavaOne , San Francisco. 30th Sept - 2nd Oct - GOTO Aarhus - very pleased I can make it this year! 17-18th Oct - GOTO Berlin . ...
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Popular posts from this blog

Dissecting the Disruptor: What's so special about a ring buffer?

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Recently we open sourced the LMAX Disruptor , the key to what makes our exchange so fast.  Why did we open source it?  Well, we've realised that conventional wisdom around high performance programming is... a bit wrong. We've come up with a better, faster way to share data between threads, and it would be selfish not to share it with the world.  Plus it makes us look dead clever. On the site you can download a technical article explaining what the Disruptor is and why it's so clever and fast.  I even get a writing credit on it, which is gratifying when all I really did is insert commas and re-phrase sentences I didn't understand. However I find the whole thing a bit much to digest all at once, so I'm going to explain it in smaller pieces, as suits my  NADD audience. First up - the ring buffer.  Initially I was under the impression the Disruptor was just the ring buffer.  But I've come to realise that while this data structure is at the hea...
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Dissecting the Disruptor: Writing to the ring buffer

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This is the missing piece in the end-to-end view of the Disruptor.  Brace yourselves, it's quite long.  But I decided to keep it in a single blog so you could have the context in one place. The important areas are: not wrapping the ring; informing the consumers; batching for producers; and how multiple producers work. ProducerBarriers The Disruptor code has interfaces and helper classes for the Consumer s, but there's no interface for your producer, the thing that writes to the ring buffer.  That's because nothing else needs to access your producer, only you need to know about it.  However, like the consuming side, a ProducerBarrier is created by the ring buffer and your producer will use this to write to it. Writing to the ring buffer involves a two-phase commit.  First, your producer has to claim the next slot on the buffer.  Then, when the producer has finished writing to the slot, it will call commit on the ProducerBarrier . So let's look at...
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Dissecting the Disruptor: How do I read from the ring buffer?

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The next in the series of understanding the Disruptor pattern developed at LMAX . After the last post we all understand ring buffers and how awesome they are.  Unfortunately for you, I have not said anything about how to actually populate them or read from them when you're using the Disruptor. ConsumerBarriers and Consumers I'm going to approach this slightly backwards, because it's probably easier to understand in the long run.  Assuming that some magic has populated it: how do you read something from the ring buffer? (OK, I'm starting to regret using Paint/ Gimp .  Although it's an excellent excuse to purchase a graphics tablet if I do continue down this road.  Also UML gurus are probably cursing my name right now.) Your Consumer is the thread that wants to get something off the buffer.  It has access to a ConsumerBarrier , which is created by the RingBuffer and interacts with it on behalf of the Consumer .  While the ring buffer obviously n...
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