Archive for January, 2009
Some good press – Thank you!
Just a quick shout to our good friends from the Internet division at L’Echo, Sarah Godard and Roland Legrand whom we met at the LeWeb conference in Paris this year.
Sarah just wrote her first post on her new blog, Nekstr, and called on us as having “undeniable perseverance” and “a wild imagination“. We are very excited to hear such keen words! And from here we send our biggest gratitude for such amazing words! This year we’ll keep it going and will unveil some great new features and hopefully, some cash.
For all the startups out there, keep it tight but keep it comming, good times ahead!
The Inkzee Team
The not so simple case of folder management
Today I want to tell all our readers a little tale, the case of the folder management. Folders has been one of the most asked features we got asked for in our first round of alpha testing. Users wanted to be able to group their feeds into folders. We started an early development and suddenly realized doing it wasn’t as simple as expected.
Technology seems easy to everyone except for the tech guys. Features that seem very straight forward become real nightmares to develop. The folder management was one of those. There where 2 steps we needed to take to implement it. The first one was to add all the necessary code in the user interface that enabled the user to drag and drop feeds into folders and within folders. That part was kind of easy, just some Javascript code here and there.
The second part wasn’t easy at all. We needed a way to store all the positions of all feeds and folders for a given user at any time. The easy way was to create a list to store the feed with the user’s position. Problem was that we needed to be able to reorder that list. That meant we needed to be able to change all the feeds ranking when a feed was reordered. Doing that translated into a lot of write operations to that list (and in conclusion to the servers disk). To those that aren’t tech geeks, write operations to any hard drive are very expensive, they take a long time and a lot of resources. Though if you want your servers to keep up with a big load of web traffic you need to minimize the number of write operations.
So we had this problem, if we had to change the ranking of all feeds every time some user reorder one of them, it meant a lot of write operations. The best case scenario was that the user dropped a feed at the end of this list, and so, we only needed to update this feeds rank. The worst case scenario was having the user drop a feed at the beginning of the list. In that case we needed to update all the other users feeds rank. When this list has only 10 feeds, then it’s ok, but if the list is as long as 800 feeds, those are a lot of write operations. Finally, if you start thinking we could have several users dragging and dropping feeds simultaneously, the number of possible write operations in the worst case was alarmingly high.
To solve the problem we partitioned the rank space so that ranks had a gap of x numbers in between. That allowed us to minimized the number of ranks we needed to update at a single moment. This added an extra layer of difficulty as we needed to track the number of free slots available before we needed to reorder the whole feed list.
At the same time we needed to track if a feed was being dragged, before or after another feed, before or after a folder or if it was being dropped inside a folder. So we had to check the type of operation, where, which folder and if we had free slots there.
When we finally had all this stuff right we had to translate this internal structure into the export / import mechanism that produces or reads opml files (xml files). We needed to be able to read an opml file with folders and translate it into our internal representation and ranking list so it would be correctly displayed to the users.
All in all, it was fun but a very hard work for something that initially seemed so trivial to accomplish. The system is working now and apart from eventual glitches it should work. We still want to get a better UI for the drag & drop thing as it seems to us it’s still a little bit clumsy, but we’ll get there.
So now you know that even the simplest feature requires a hard work, so choose wisely what you want us to develop next 
God bless the private invites
Hi all,
After some finally tweaks, we managed to push another release today and finished migrating all users from the old alpha architecture. We were so excited, we decided it was time to send some more invites to some more users that have been waiting for it for ages! (We really regret that, sorry guys!).
Suddenly what we can only define as a shit storm came our way. Servers were on fire, even though we didn’t send too many invites. Problem is that our system scales with the number of feeds each users has. Some of our new alpha users are really feed junkies (you know who you are! 
) and really pushed the total number of feeds the system manages really fast. We are throwing some stats so you get some idea:
As you can see, the number of feeds being tracked by Inkzee internally nearly triplicated in a 20 minute span. We are storing, displaying and sorting 32,859 posts right now and growing fast.
In the process of managing such a large amount of new feeds some parts of the backend went belly up. We are investigating it now and we hope we can fix them soon. Even though some things broke, they weren’t critical parts so the system recovered from the failures pretty fast which is good news.
The moment we stabilize the system again we’ll continue sending new invites. Right now we are also focusing in adding new features. The next one in our roadmap will be the ability of creating custom filters and keyword alerts. We hope to release that some time next week.
As usual, thanks a lot for your patient and keep coming, but gently
The Inkzee Team
