I thought I’d use our new 3D city view visualizations to have a closer look at Apache-Cassandra, a very popular and successful open source project that implements a NoSql database. I know from previous analysis runs of the same software that it already had problems with structural erosion. Years ago I analyzed Cassandra 1.2.6 and found pretty big cycle groups for Java files as well as for packages. Maintainability Level was only 9.4% (everything under 50% is concerning) while the metric “Propagation Cost” has a value of 62%. That means that every change will affect 62% of all code directly or indirectly which also is not a good thing because it significantly increases the chance of regression bugs.
Before you say “this image is useless, you cannot see anything there” let me tell you that I agree. The point is to make sure that your software never ends up in that situation. This big cyclic conglomeration is making it close to impossible to modularize Cassandra or to put any kind of architectural model on top of it.
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