Greetings Jakub > So perhaps we should expand "Commit graph labeling for speeding up git > commands" idea, splitting it into two possible ways of working in this > project: the more technical 'Generation number v2', and 'Interval labels > for commit graph' which is more of research project? Which should be > put first, then? I would suggest working on generation number v2 first because: - We ship improved performance *sooner*. - I find it easier to shift from simpler to more complex systems. On a personal note, I would be able to do a better job at working on generation number v2 than on interval labels. While reading through the papers mentioned was fun and full of a-ha moments, I find building things more fulfilling. I would be glad if either you or Derrick opt for mentoring it. You could read my proposal at the link below. It is very rough and I haven't proofread it yet. I will send out a more formal proposal once the direction of this project is decided. https://github.com/abhishekkumar2718/GSoC20/blob/master/graph_labelling.md **Too long, didn't read** - Commit graphs are small to medium-sized (compared to problem sizes observed in graph-theory literature) sparse graphs. They have unusual properties compared to more conventional graphs that can be exploited for better performance. - Most of git's reachability queries are negative and using a negative-cut filter improves performance more than a positive-cut filter. - Implementing and maintaining a two-dimensional reachability index is hard and does not offer justifiable performance gains. - We plan to use corrected commit date as the generation number v2 because it is locally computable, immutable and can be incrementally updated. - If git ever considers a two-dimensional reachability index, either post order DFS, GRAIL or an index based on commit date would be good starting places to explore. I go in more details about GRAIL, FERRARI and PReaCH, explaining briefly how they work, their advantages, and disadvantages. > Note that for example "Convert scripts to builtins" idea is in similar > situation: it is also many projects in one. Regards Abhishek
