Archive for the 'english' Category

Ruby’s garbage collector and caching

My current job at Delta Projects is great in terms of working with high volumes. The fact that we serve around 50+ million ads a day creates the need for different approaches in terms of storing and retrieving data. Our ad servers for example are completely independent from the backend. Business logic and models are exported as code in our backend systems and pushed to our array of ad servers. Content itself is put into a git repository and is updated regularly by the ad servers. The backend system is unaware of which ad servers there are. Raw data is pushed back from the ad servers and processed later.

Because we want to serve ads as quickly as possible (and creating the least possible delay on the page that uses ads that are served by us), we cache ads on the ad servers. Some weeks ago however, we noticed that CPU usage was increasing at a very high rate over time. Memory usage was also increasing, but not as quickly as the CPU usage. The memory increase was caused by the fact that we stored ad meta data in memory inside our application. Since we run around 10 Unicorn processes, an ad would be in memory 10 times, but that wasn't such a big deal, since we run with a lot of RAM. The CPU consumption was more worrying. After some investigation we found out that when all ads are loaded in memory, we had a lot of string objects in memory (around 1.2 million) that were retained, since a global cache array would keep a reference to them. In other words, the objects are never garbage collected. But, since ruby 1.8 has a non-generational GC, all objects are inspected by the GC and having 10 processes performing a GC run over 1.2 million objects every now and then, caused a lot of CPU load.

So, we needed a better way of caching. Memcached was our first idea, but having yet another process on which we depend didn't feel like such a good idea. Since it's a local cache, my colleague Kalle came up with the idea of storing our cache data on tmpfs. Our application takes care of filling the cache (since it serializes ad meta data) and reading from it. Invalidating cache items is now done through a git hook, that simply removes a file that has been updated or deleted from tmpfs.

This al lead to a tenth of the memory consumption and  a lot less and constant cpu usage.

Published at February 20, 2010 in english, ruby and work. 0 Comments

Awesomeness and a broken finger

Sorry, I'm a bad blogger. I promised a lot of people to blog about my move to Sweden, but I haven't. And since I still don't have a mobile phone subscription, I can't use twitter as I used to, every moment of the day. The short version is in the title: Sweden is awesome and I broke a finger.

The somewhat longer version is that life is great here. Me and Kasia are doing great; I'm having such a great time being with her. Work is great too. I'm doing pretty cool stuff, both coding and tinkering with networks and unix systems to squeeze out every possibility to get even better performance. We're currently serving 50 million ads a day (and yes, online ads.. I sold my soul) with just a hand full of servers, running a Ruby application. The team I'm working with consists of only smart an experienced people, which makes it even better. I'm learning every day.

My Swedish isn't really great yet. I've signed up for a course, but I have to wait some months to start, since it's fully booked. In the mean time I'm doing some Rosetta Stone, but not so much. I hear a lot of Swedish at work, but everybody speaks English, so there is no real need to speak Swedish. Reading is not so hard, since there are a lot of commonalities with Dutch, but speaking is a lot more difficult.  However, I had a small breakthrough yesterday, when I went to the hairdresser. She doesn't speak English, so I was forced to speak Swedish and I had an actual (and pretty decent) conversation with her! I guess it's all about not being shy and just try.

Swedes are friendly people and very modest. Business is somewhat different than in the Netherlands. For example, meetings are different. In the Netherlands, often people go into a meeting with a goal. Decisions should be made. A general consensus is OK, but there should be a result after a meeting. Here it's different. Meetings are for listening to people and talk about the stuff that needs attention, but decisions are made at the coffee machine. I read some articles about this and some said that Swedish mentality is closer to the way people do business in Belgium, but I'm not sure. Belgians seem far more hierarchical; one person is the boss. Here, it's more about compromises and talking.

Some people asked me if Sweden is expensive. I guess it can be, but apart from the alcohol, it feels a bit like the Netherlands. Of course my salary is in Swedish Kronor, so it's harder to compare, but I don't really have the feeling that products are that more expensive here. I must admit that I'm not very price aware, so it's more a gut feeling. VAT is higher; 25% and 12% instead of 19% and 6%, but I guess you get a lot back from that. Alcohol is excessively expensive though. Half a liter (note to Wayne: "I'm sorry sir, I don't know what a liter is") of beer costs roughly Euro 6,50 in a bar and a Mojito is roughly Euro 13,-. Next to that, you can't buy wine or (normal) beer in the supermarket. There is only one company that sells alcohol and it's run by the government and there a bottle of beer is about Euro 1,50. In the supermarket you can buy 3.5% vol. beer, but that just tastes like water.

But you get a lot back for the stuff you pay. Public transport is good. I think it's better than in the Netherlands. Metro runs pretty much on time (in the Dutch meaning of the word) and often. Swedes tend to have a thing for time. If the metro is 3 minutes late, it's late. 13 past the hour isn't a quarter past, it's 13 past. Interesting difference.

Another thing you get is health care. Paying for that is done through taxes, directly. Not through strange systems with insurance companies. If you need health care, you will get it. Everybody is equal. The first 900 kr (90 euro's) per year, you'll have to pay by yourself, and then it's free for 365 days.

How do I know this? Experience. 3 weeks ago I broke my right ring finger. I went snow boarding with a friend and at the beginning of the first run, I touched the ground with my hand while trying to keep balance. It hurt, but I thought that it would be just a contusion. It wasn't even a cool crash or anything and I had been standing on my board for only 5 seconds. I went to the first aid at the slope to have it checked, but the guy there said it was probably only a contusion and that it was just a little bit swollen. so, I continued boarding for a couple of hours. My finger turned blue and purple the next day, but when the swelling disappeared after a couple of days. I still couldn't move it and it still hurt, so I decided to see a doctor and after some x-rays it turned out to be broken. At the hospital, I got a cast that is coming off today. I'm actually sitting at the hospital while writing this piece. I just had x-rays and I have a doctors appointment in an hour. Hope it healed a bit and that they'll take off the cast, because it's really uncomfortable and typing is pretty hard.

I'll try to make some more time in the future to blog and I hope I can get a mobile subscription soon, so I'm able to be online a bit more. But I'm alright!

Published at February 5, 2010 in english, life and sweden. 2 Comments

What were you doing in Stockholm, Kevin Rose?

Last week, I went to Stockholm, Sweden, with two friends. In some trendy club, we met Kevin Rose, or at least, a guy that really looks like Kevin. Now, there are a couple of theories here:

  • It is Kevin, but he wouldn't admit it
  • Kevin was separated at birth
  • Kevin was cloned
  • It's Hippie Glen, dressed up as Kevin

Anyway, here are the pictures. Let me know what you think.

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PS. We have no clue why this Kevin is pointing at the camera.. Could it be some habit?

Published at March 22, 2009 in english, fun and travel. 0 Comments

Birthday wrap-up

Some weeks ago, I got one year closer to the awful and frightening age of 30. The counter is at 28 now and I'm really afraid of losing my hair and turning gray after 30. Since I have my fathers hair, it's not likely that I'll get bald soon, but grey for sure. Anyway, this year, celebrating my birthday was awesome; I celebrated two times.  My actual birthday, I spent in Russia, which for obvious reasons was great. I flew east-bound on the 6th and turned 28 the same night at 0:00. Lena gave me my present (which I actually took with me from the Netherlands, but I didn't know what was in that strange looking package) just after midnight. She got me a binary watch, the ultimate geek wrist jewlery! The next day, my Russian family prepared a very nice lunch and I got meet Lena's grandfather. Communicating was hard, since my Russian is still very basic and her grandfathers English is pretty rusty. Anyway, I think we hit it off pretty well.

In the evening we went to a restaurant to celebrate with my Russian friends. Lena's family gave me half a day in a professional music studio to record the vocal tracks for a song I wrote for her a few months back. On Saturday we went there and it was super. I was pretty nervous to sing, but after 4 attempts, the sound engineer had enough stuff to make a mix. After 3 hours of montage, the vocals were ready and I was handed a CD. And no, I'm not going to publish it.

The next day, we were invited to a wedding of Lena's best friend. Very nice and interesting, since it was my first Russian wedding. Weddings there and here are different, but I'll not go into the details now. The experience itself was great. On Monday, the inevitable moment came to fly back. Always hard, but I managed.

The second part of my birthday was the Dutch version. I invited some Dutch friends and we celebrated at my house. The atmosphere was nice, although the party turned out to be a circle-party (typical Dutch party where people sit in a circle talking and I actually hate these kinds of parties), but the all beer and wine finished, someone puked and most were pretty drunk. After midnight we went out to the city center to continue celebrating. The pinnacle of the evening was a round of Vodka, where one of my friends decided to not pour the drink into his mouth, but splashed it into his eyes. Zanas!

Published at November 27, 2008 in english, life, russia and travel. 0 Comments

And back online..

Today I realized that it's been over a month that I've blogged anything here. Lately, I've been kind of busy and spend less time online. Also other media have suffered my absence latetely. Various people even asked if I'm ok and asked about stories about NYC and Russia.

Actually, nothing happened. I'm ok, but kind of busy lately. In short, NYC was great; the HOPE conference was awesome with a lot of interesting speakers, a lot of fun stuff to do and to see. I really enjoyed my time there. The rest of NYC was also nice; I saw the stuff I didn't see before (couple of museums, neighborhoods, building) and with Bart and Ronald, I had a trip (in a Ford Mustang) to Atlantic City.

Russia was also great. Of course, the main thing was my girl and this was awesome. Therefore I'm back in Russia in the beginning of September. Next to that, I took extra Russian classes. I learned a lot, maybe too much. I really need to go over the lessons again to process the boost of information I got.

After coming back home, I really missed Russia. Obiously, her, but also all other people I got to know, the food, the language, the city. So, now I'm still recovering. Since a lot of people that work in my projects were on a holiday over the last two weeks, I've been working a lot to fill in for some of them, but now most of them are back and things are getting back to normal.

All in all, I'm feeling ok, maybe a bit tired from last weeks. I didn't really take rest during my holidays, so I think I'll need to recharge a bit over the coming weekends. And obviously, I can't wait to travel to Russia again!

For the people that missed me online: I'm back :)

Published at August 18, 2008 in english, life, russia and travel. 1 Comment

NYC again!

Currently I'm in New York City again. I'm now sitting on a bench in Central Park, because apparently they have wifi here.

The city is still great. I'm very relaxed and at ease and feel great. Travel journals will come later and especially some reports from Hackers On Planet Earth, next weekend.

Published at July 12, 2008 in english, life and travel. 0 Comments

It’s not about usability

When it comes to applications or websites for the masses, it's not about usability, it's about userbase. I noticed this yesterday, when a new friend of mine invited me to use facebook. Currently I'm using Hyves, a Dutch social network to keep in touch with friends and Linkedin for some business contacts. Since a few months I'm also familiar with vkontakte, a big Russian network, but I don't have my own account there. During my recent trip to St. Petersburg, I made some new friends and one asked me if I had a facebook account. I didn't have one yet, but I decided to get one, just to keep in contact with my international friends. I've been playing around with it for some time now and I must say that it's so much better than Hyves. Basically Hyves sucks; it's slow, ugly and very hairy in navigation. But why is it the biggest network in the Netherlands? Not because it's user friendly, but because everybody uses it. Obviously the nature of social networks contributes to this kind of behaviour; who wants to be on a network without any friends? But I think this statement is also true for a lot of other software. Since the days of byte-islands have passed a long time ago, it's necessary to interface, and so, using what everybody uses is key. This is true for file formats, but also for usage of applications in general. The people I know are mostly geeks or have some affinity with IT. For them it's easy to use something out of the ordinary, because they can manage (converting file formats, jumping through holes to get their linux machine hooked up to a mac, finding out how a different system works, etc), but for the masses the most important thing seems to be able to do what everybody does. Only to be able to ask a non geeky friend how things work. The geeky geeky friend wouldn't know it anyway; my usual response normally is "ooh, I don't know this windows stuff.. I use Linux.."

Published at June 30, 2008 in english and techno stuff. 0 Comments

Birthday in Russia

Last week was a busy, but great one. Friday morning, Jur and I took the train from Utrecht CS to Schiphol airport. There we first had to pick up our tickets, since Rossiya Air doesn't do the nifty e-ticketing yet. After the woman behind the counter finally found our tickets, it was check-in time. All went smoothly and after jumping the queue at the passport control by waving our Privium passes, we had some time to buy stuff at the duty free shops. Since Jur didn't have a present for Elena yet and we needed some extra orange stuff for the upcoming match we spent some money in one of the many souvenir shops that are at the Schiphol terminals. The rest was pretty standard; walking to the gate and finally boarding the plane.

After 2.5 hours in the air, we arrived at St. Peterburg airport. Customs took some time, but finally I saw her again in the arrival hall! It had only been 2 weeks since we'd been apart again, but I was so glad to see her again. By bus and metro we went to the apartments we rented and there, we had to say goodbye to Elena, since she had snuk out of the office and had to finish some work until 21:00. This was OK, since there was some unfinished business I had to take care of. First we went to the bakery to pay for the birthday cake I ordered. Katja, a friend of Elena helped me with preparing earlier on and helped me communicating with the girls at the bakery, but only by phone. Finally I payed and understood that the cake (with Miffy/Nijntje on it) would be ready at 16:00 the next day.

Next stop was the restaurant. I called them before and already made a reservation for 15 to 20 people, but they asked me to come to the restaurant before Saturday to discuss the evening. Since we had about 3 hours to take care of this and the restaurant was 45 minute drive from the city center, we took the metro to a train station on the north side of the city from where we wanted to take a train. When we arrived at the metro station we discovered that we took a big detour and found out that we just missed the train by 5 minutes. The next train would go an hour later, so we decided to take a taxi to the restaurant. After about 30 minutes we arrived there and had a nice meeting with an English speaking waitress and the manager. We created a menu and talked about all things involved. At first, the manager didn't allow us to bring our own cake, but after giving her a very sweet look, she finally agreed. All set, we took a bus back to the city and picked up Elena from her work. Here we met some people I worked with in a previous project and finally went to have dinner.

After dinner, Elena showed us a part of the city, next to the Neva river, where all sorts of festivities were, since it was the day that a lot of high school kids graduated. There was a big concert next to the river and lots of people looking at boats on the river. The atmosphere was very good and all people were happy. During this time of year, the sun doesn't go down and I found it pretty awkward to be on the street at midnight without complete darkness. The sun is somewhere on the horizon at 2 o'clock in the morning and it never gets completely dark.

Somewhere at 1 AM, Elena had to go home, so I decided to bring her (we took a car) and went back to the apartment. Jur and I decided to go out for a beer and finally found a nice pub where we could sit outside. Then it was off to bed.

The next day, Jur and I went to get a car we rented, but we couldn't find the rental place so we decided to skip this because we didn't need a car anyway. After, I went to Elena's house to meet her parents for the first time. I'm not a hero when it comes to the meet-the-parents-thing, but now I was even more nervous, since I didn't know what to expect in terms of the language barrier and cultural differences, but finally everything turned out very well. I felt very welcome and after the tour around the house, I had nice conversations with both Elena's mom and dad. I felt at home very quickly.

After some time Elena had to go to the hairdresser to get a new haircut for the evening and I went with her. The girl at the salon did a great job and she looked stunning. After she changed clothes at home we were off to go to celebrate her birthday. First we took a taxi to the apartment, so I could change my clothes and met there Oleg, a friend of Elena. I quickly went to get the cake, which turned out great. Then we took a taxi to the restaurant.

The restaurant was about 40 minutes by taxi and we arrived secondly, just after Julia and her boyfriend Andrei. The table was made and the menu was printed and closed with a seal. The cake was put in to the fridge by the staff. In 30 minutes all guests were there and the party started. Elena got a load of gifts from her friends and lots of flowers. For starters, guests could choose from the menu and as a main course the restaurant prepared a big meat and fish dish, a couple of big plates on the table where people could take from. The food was really good and very tasty and also the service was super. Dirty cutlery was replaced instantly and our waitress was very friendly, but also nice to look at. Especially Jur found her very interesting. Somewhere during the evening, Elena whispered to me that she would get the girls phone number if Jur didn't ask himself. As far as I know, everybody had fun and enjoyed the food, drinks and talks. After dinner we went for a quick walk to the beach, just to look at the sun going down and get some fresh air.

When we got back after 30 minutes, the soccer match between the Netherlands and Russia was about to start. Before, we had decided to watch it at the restaurant, since they had put up a big screen. Even though Jur and I were the only Dutch guys there, we still were dressed in orange. The match was very exciting, but finally Russia turned out to be the stronger team. Too bad for my country, but I think we were lucky to be in Russia when they won and not back home, since the party then really started. People dancing, shouting, singing and going completely crazy. One random guy in the restaurant came to us to thank for the game and was shouting "My friends! My friends" all the time. After taking some pictures with him, I decided to give him my orange "Holland" cap. After some time, we decided to go, but not before Elena got the waitress' (called Maria) number for Jur.  We got a ride from Slava back to the apartment. Since I was completely exhausted, I decided to go to sleep, while Jur decided to go out. He wanted to go to the city center, but since all bridges open during the night, his ride there took him over an hour, but apparently he had a great time there, partying with people in the street.

The next day, I spent some time with Elena in the city center, before going to her parents house again for dinner. This time, Jur joined us also and we had great Middle Asian food, prepared by Elena's dad. After lots of nice stories from her parents, we went back to the city center to check St. Pete's night life. Finally we ended up in a place called Rossi's with lots of girls on the dance floor. After some time, Elena said goodbye, for she was very tired. Jur and I stayed until very late and drank too much.

The day after, we decided to go to Peterhof, the Russian Versaille, but first, Jur and I had to go to some office to get a registration for our visa. After we met with Elena to go to Peterhof. At first, Maria would join us, but since she had exams, she didn't have time. However, she told us that I had left my credit card at the restaurant, but that she woulld take it with her, so we could get it from her. By hydrofoil boat it took about 30 minutes to arrive at Peterhof, which is located on the south side of Spb. Peterhof is a lovely place with lots of fountains, golden statues and nice trees. After walking around for some time and taking pictures, we took a bus back to the city, where we had Sushi at a great restaurant and some cocktails at the 7SkyBar, a trendy bar located on the top floor of a big shopping mall. After this I went back and off to bed and Jur decided to go to the city again to party.

The following day there was news that the invitation for my Russian business visa was ready. Also, we had to get our registration. First Jur and I went to the registration office, only to find out that the registration wasn't finished, but should be picked up later that day. Jur would take care of this after his visit to the Hermitage museum. Me and Elena met in a different part of the city to get my invitation. After this, Maria called where we could meet her so she could give me back my credit card. We met her, but she didn't have much time to talk, because she was going to celebrate her holiday, but told us that we should really call her next time we were in Russia. Then Elena en I went to her parents place for dinner again. Jur was also invited, but spent 2 hours in the queue for the Hermitage, so he decided to get some dinner by himself after the museum. After lovely dinner and a nice conversation, we went to the theater to watch Tchaikovsky's Nutcracker. Elena got two tickets from her colleagues for this beautiful ballet. Since we were in a big traffic jam while driving there, we were about 10 minutes late. Our tickets said that we had places in a lodge somewhere, but since we were late, they put us in a very nice place, just in front of the stage!

After the ballet, I went back to the apartment again and said goodbye to Elena. On the way, I bought some beers to celebrate our great time in Spb with Jur. At the apartment we drank a bit, just until Jur got a text message from a girl he had met in a taxi, the night before, asking him to join her at a birthday party somewhere in the center. Even though it was going to be a short night (we had to get a taxi at 6 AM back to the airport), he decided to go there anyway. I packed my stuff and fell sound a sleep at 1 AM, for I was exhausted.

At 5:45, my alarm clock sounded and I got up, took a quick shower and waited for the taxi. Elena called that we should go downstairs, because she arrived. 30 minutes we were at the airport. After standing in a queue for security it was time to say goodbye. This part is always the hardest. After a long kiss, I finally went through security. Before check-in we had to wait again in a very big queue, but finally we checked in our stuff. Then through customs, security again and then to the airplane.

Some 2.5 hours later, I arrived on Dutch soil again. Completely exhausted, but it was all worth it. The hardest is the emptiness that sets in after saying goodbye, but I'm going back to Russia in 25 days. I decided to shorten my trip to NYC by one week and then go to see my girl again.

Published at June 29, 2008 in english, frustrations, fun, life, russia and travel. 0 Comments

Euro 2008 – Russia vs the Netherlands?

Looks like things are really coming together. As I wrote before, I'll be in Saint-Petersburg the coming weekend. People who watch the Euro 2008 soccer championship know that the Netherlands is through to the quarter finals, but who will they play there? Well, this really depends on who will win the match Russia vs Sweden. The one who wins will be second in that group and will play the quarter finals agains the Netherlands. Obviously, I hope that Russia will win, but not only because I have a special connection with that country, but also because it would be very nice to watch that game in Russia itself.

I've already spoken about this with a Russian friend of mine and he already booked seats at a sports bar, somewhere in the city center of Saint-Petersburg. Elena also wants to see this match, so after her birthday, we will go there to watch the game.

Published at June 16, 2008 in english, life, russia and travel. 3 Comments

Birthday organisation

As I wrote before, I'm going to be in St. Petersburg from next Friday until the Wednesday after. Obviously, I'm very much looking forward to this and really can't wait to arrive there. Since it's Elena's birthday, but she didn't want to organize something big, I decided to organize the party. Because it should be a surprise, I can't tell too much about it here, but I'm almost ready in organizing it and I hope it's going to be a blast. It's very interesting to organize a birthday from 1700 km away and do much of it online. Luckily, some friends of Elena are very willing to help me, which makes things easier.

Next to that, the place to stay has finally been arranged. Since the 21st of June is mid-summer night (in Russia, they call this white nights, since the sun will not go down), the city is swamped with tourists and other people that want to be there for a lot of festivities. As far as I heard, that weekend there will also be lots of festivities because of students graduating and thus partying. Elena called more than a hundred hotels to check for vacant rooms, but all hotels were booked. Finally she found an apartment in a nice location.

So, all is set and I'm really excited to be in Russia again! I even found a solution for my cats; Sanne offered to look after them and will sit my house as well during my stay in Russia. Super!

Published at June 11, 2008 in english, life and travel. 0 Comments
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