Some readers are not getting the point. When running node in a production environment, it is assumed that the app has no blatant infinite loops. Yes, that would block the event loop and prevent anything from running, but if you've done that, you should take Intro to Node 101, or maybe the remedial class...
In a production environment, we're concerned about long running events that might be blocking the event loop. If your code is doing database calls, then it's yielding to the event loop. No problem there. But then if you run a bunch of processing on that using synchronous code, and that processing takes longer than whatever threshold you give in the code I posted, then it will tell you. We're not concerned as much about overall request time, because during the time it's processing the request, it's probably yielding. For newbies, yielding means that you perform some action and pass it a callback, and when that action is done, it calls the callback. Users see this all over in node code. That doesn't necessarily mean it yields though... Case scenario: we had a bunch of db calls to load data that would be processed (sorted, organized, transformed, etc) and converted to json and then fed to the client. That db calls yield each time a db call is made. No problem. The processing was all linear programming. Problem: for large data sets it was taking over our threshold. When you have more concurrent requests than the number of instances of node (we're using cluster) then every instance is busy and your server goes unresponsive. BAD news. We had to change some calls to accept a callback, and then it would call the callback inside a process.nextTick(). That made the code async, and the problem disappeared. We could ramp up with hundreds of users and the users with only a little data got served fast, the users with lots of data not quite as fast, but at least they weren't blocking other users. People often misunderstand how to build server-side apps with Node. With async coding in node, you can easily outmatch performance for lots of other environments. With synchronous code in node, you can easily have a dead server. Node is great, but it's oh-so-easy to shoot yourself in the foot. Gotta be really careful about excessive runs of synchronous code. -- Job Board: http://jobs.nodejs.org/ Posting guidelines: https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines You received this message because you are subscribed to the Google Groups "nodejs" group. To post to this group, send email to nodejs@googlegroups.com To unsubscribe from this group, send email to nodejs+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nodejs?hl=en?hl=en
