Large code refactoring projects can consist of hundreds of refactoring rules that are applied iteratively to make 
code  easier to maintain. Visualising the refactoring process can help engineers and stakeholders understand how  chains of refactorings were applied and to gain more confidence in the produced result. An apparently suitable existing visualisation using log-based behavioural differencing suffers from scalability issues when applied to industrial-size cases. We propose an adapted visualisation tool that highlights those parts that really changed in-between iterations of a large refactoring process and collapses those parts that remain stable. We show that our alternative visualisation scales well on large logs of a process with many possible refactoring chains, of which significant parts are shared. Consequently, it allows engineers and stakeholders to quickly answer relevant questions about what happened during the refactoring process

A Scalable Log Differencing Visualisation Applied to COBOL Refactoring

The ninth IEEE Working Conference on Software Visualization (VISSOFT 2021) builds upon the success of the previous eight editions of VISSOFT, which in turn followed after six editions of the IEEE International Workshop on Visualizing Software for Understanding and Analysis (VISSOFT) and five editions of the ACM Sympo0sium on Software Visualization (SOFTVIS). In 2021, VISSOFT will take place and be co-located with ICSME.