Round robin DNS records are a technique for distributing load across public facing web servers. As an experiment we tried using them in order to distribute load inside of a cluster. We found this approach didn’t work. In this post I’ll discuss round robin load balancing, how it works at a high level, what we did with DNS, why it didn’t work, and what can be done instead. ...
Performance counters can be implemented in applications to help operators determine where bottlenecks are in the design. Microsoft has a decent page, that’s somewhat Windows centric, about performance counters. This post is about implementing the most basic type of counter, a value which monotonically increases, in JavaScript for NodeJS and the performance implications of different designs. ...
In the last few weeks I have been slowly learning about the cocos2d-x framework. cocos2d-x is a C++ based cross platform game engine. The makers of the engine also produce a UI creation GUI called Cocos Studio. Today’s post is a brief one about loading scenes from Cocos Studio into a cocos2d-x based application. ...
Operator precedence determines the order [Operator precedence determines the order]2 and binary operators are executed. In many situations, knowing basic mathematical operator precedence (for +,-,*, etc) is enough. In other situations not knowing the specifics of language can lead to hard to find errors. Quickly, in JavaScript what does 'the boogeyman ' + false ? 'is scary' : 'is not scary' evaluate to? ...
Recently I started writing a new web application which uses OData V4 as the protocol for passing data to back and forth between the JavaScript client and ASP.Net server. The client is written using AngularJS which doesn’t have any built-in facilities for working in OData APIs. In order to avoid writing my own OData message handler I used the Apache Olingo library to handle the grunt work of sending requests and receiving responses. I wanted to encapsulate the Olingo library in an AngularJS service in order to make using it easier, the following post details how this was done. ...
Today we will look at whether it’s worth developer time to pre-size ArrayList objects in Java application code. We will take a similar approach to the one taken in a prior post on how long it takes to handle an exception in Java. ...
Today post is exceptional, we’ll take a brief look at the time cost of throwing and re-throwing exceptions and put that time cost in context. To be specific, we’ll look at the timing information for a set of exceptions which might be found in a typical 3-tier business application. In our example the exceptions are thrown and caught in hierarchical order in order to promote separation between the tiers of the application. ...
Previously we have discussed one approach and gave some implementing code for providing time zone adjusted date times to client web applications. Within the space of user facing web applications there are few different approaches to handling the storage and transmission of date time information. Today we will look at a couple broader themes for delivery of date times to client applications from servers and some thoughts on how to do it well. ...
This is short post about a couple issues that end users might run into when using a method of displaying dates I described in a prior post. In short, Microsoft Internet Explorer 9 cannot parse certain types of ISO8601 dates correctly and Google Chrome does not track the system’s time zone correctly. ...
A quick tip post on using Knockoutjs to create a certain type of common web UI component. The short and sweet summary is that I’ll show how to create a shuttle control using two select boxes that are bound to arrays of Javascript objects (instead of simple value types) using Knockoutjs. Before getting to that though I’ll provide some background on the various component used to create the UI. ...