The point of --changed-since is to do less work. But there are real world reports of the --changed-since taking multiple minutes even on beefy CI machines, which is large fraction of the entire build time. "This performance bug is introducing 3-4m delay to our pipelines right now which represents roughly 30-40% of a build pipeline."
Consolidating several other discussions:
In #23228 @jasonwbarnett created a synthetic reproduction at https://github.com/altana-ai/pants-changed-dependents-perf-repro
Note: To the extent the problem boils down to "dependency inference", see also #18911 For memory and large number of targets see #22393
The point of
--changed-sinceis to do less work. But there are real world reports of the--changed-sincetaking multiple minutes even on beefy CI machines, which is large fraction of the entire build time. "This performance bug is introducing 3-4m delay to our pipelines right now which represents roughly 30-40% of a build pipeline."Consolidating several other discussions:
In #23228 @jasonwbarnett created a synthetic reproduction at https://github.com/altana-ai/pants-changed-dependents-perf-repro
Note: To the extent the problem boils down to "dependency inference", see also #18911 For memory and large number of targets see #22393