On Tue, Nov 06, 2018 at 12:34:47PM -0800, Derrick Stolee via GitGitGadget wrote: > From: Derrick Stolee <dstolee@xxxxxxxxxxxxx> > > A git push process runs several processes during its run, but one > includes git send-pack which calls git pack-objects and passes > the known have/wants into stdin using object ids. However, the > default setting for core.warnAmbiguousRefs requires git pack-objects > to check for ref names matching the ref_rev_parse_rules array in > refs.c. This means that every object is triggering at least six > "file exists?" queries. When there are a lot of refs, this can > add up significantly! I observed a simple push spending three > seconds checking these paths. Thanks, this fills out the details from the cover letter a bit better. > The fix here is similar to 4c30d50 "rev-list: disable object/refname > ambiguity check with --stdin". Save the value of the global > warn_on_object_refname_ambiguity variable (which is usually set to > the boolean config variable core.warnAmbiguousRefs) and change the > state to false. Do this only during the get_object_list() method > which reads the objects from stdin. I think this parenthetical isn't quite right. We never change the value of warn_on_object_refname_ambiguity based on user config. It's just that if warn_ambiguous_refs is off, we do not even bother looking at the object_refname variant. So we'd never expect to see anything except "1" in our save_warning variable. Doing a save/restore is just about code hygiene and maintainability. Other than that minor nit, this whole thing looks good to me. -Peff
