On Tue, Mar 26, 2019 at 08:22:23AM +0900, Mike Hommey wrote: > Recently, I've noticed that whenever the auto-gc message shows up about > being spawned in the background, it still takes a while for git to > return to the shell. > > I've finally looked at what it was stuck on, and it's > `git reflog expire --all` taking more than 30s. I guess the question is > whether there's a reason this shouldn't run in the background? Another > is whether there's something that makes this slower than it should be. The reason is that it takes locks which can interfere with other operations; see 62aad1849f (gc --auto: do not lock refs in the background, 2014-05-25). Unfortunately making it faster is hard. To handle expiring unreachable items, it has to know what's reachable. Which implies walking the commit graph. I don't recall offhand whether setting unreachable-expiration to "never" would skip that part. But if not, that should be low-hanging fruit. (I also wonder whether there is really much valuable in keeping unreachable things for a shorter period of time, and the default should simply be to just prune everything after 90 days, unreachable or not). -Peff
