{'fraction_non_alphanumeric': 0.03223270440251572, 'fraction_numerical': 0.0, 'mean_word_length': 5.528205128205128, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Evaluation of Model Comparison for Delta-Compression in Model Persistence

Model-based software engineering is applied to more and more complex software systems. As a result, larger and larger models with longer and longer histories have to be maintained and persisted. Already, a lot of research efforts went into model versioning, comparison, and repositories. Existing strategies either record and persist changes (change-based repositories, e.g. EMF-Store) or relay on existing text-based version control systems to persist whole model revisions (state-based repositories). Both approaches have advantages and disadvantages. We suggest a hybrid approach that infers changes via comparison to persist delta-compressed model states. Our hypothesis is that delta-compression requires a trade-off between comparison quality and execution time. Existing model comparison frameworks are tailored for comparison quality and not necessarily execution time performance. Therefore, we evaluate and compare traditional line-based comparison, an existing model comparison framework (EMF-Compare), and our own framework (EMF-Compress). We reverse engineered the Eclipse codebase and it’s history with MoDisco to create a large corpus of evolving example models for our experiments.