Continuous Integration is Not About Build Systems

Keeping the build fast is often stated as an important prerequisite for continuous integration, and is also widely discussed in literature. But which importance does the capacity of the build system actually have in relation to developer behavior? Based on metrics and interview results from a large-scale industry project, we present the factors that according to the developers themselves affect how often they deliver software to the mainline. We show that the developer will deliver less frequently if the delivery processes is time-consuming, if it's too complicated to deliver or if there is no evident value in delivering often to the mainline. Behind these three main themes, we also present a range of sub-categories such as architecture, test activities and administration. The build system capacity is one of several factors which, if not considered, could result in undesired continuous integration behaviors – but other factors should be seen as at least as important.