When computing revision ownership, cache some intermediate results for performance
Ref T12319. With large datasets, the computation of which packages own paths in a revision is needlessly slow.
Improve performance through caching:
- Cache which paths belong to each repository.
- Cache the split fragments of each path.
- Cache the path fragment counts.
- Micro-optimize accessing $this->path.
- Used bin/lipsum to generate 4,000 packages with 150,000 paths.
- Created a revision affecting 100 paths in phabricator/ (these paths mostly overlap with bin/lipsum path rules, since Lipsum uses Phabricator-like rules to generate paths).
- Before optimizations, this revision spent about 5.5 seconds computing paths.
- After optimizations, it spends about 275ms.
Reviewed By: chad
Maniphest Tasks: T12319
Differential Revision: https://secure.phabricator.com/D17424