Thanks Brian, > delta compression is multithreaded That is great news that this is expected behavior and I'm not dealing with some sort of obscure data corruption. :) Now see there is `git config --global pack.threads 1` (I'm doing everything locally, so this might work for me) > reason for wanting bit-for-bit identical My plan was to have 3 pushurls and shoot one of them if it is not bit-for-bit identical to the other two. But you are right, all I need is `git fsck`. On Wed, Apr 22, 2020 at 6:15 AM brian m. carlson <sandals@xxxxxxxxxxxxxxxxxxxx> wrote: > > On 2020-04-21 at 18:07:42, Mikhail Strelnikov wrote: > > Hi, > > > > I have a repo with two pushurls configured like this: > > > > > > C:\folder\1>git init --bare > > Initialized empty Git repository in C:/folder/1/ > > > > C:\folder\2>git init --bare > > Initialized empty Git repository in C:/folder/2/ > > > > C:\folder\w>git init > > Initialized empty Git repository in C:/folder/w/.git/ > > > > C:\folder\w>git add work.txt > > > > C:\folder\w>git commit -m "Initial commit" > > [master (root-commit) 1b314f3] Initial commit > > 1 file changed, 1 insertion(+) > > create mode 100644 work.txt > > > > C:\folder\w>git remote add origin C:\folder\1 > > > > C:\folder\w>git remote set-url origin --push --add C:\folder\1 > > > > C:\folder\w>git remote set-url origin --push --add C:\folder\2 > > > > C:\folder\w>git push --set-upstream origin master > > > > > > I would expect those two folders (C:\folder\1 and C:\folder\2) to > > contain exactly the same bytes. And they did for quite some time. But > > now there is a difference in 'objects\info\packs' (and some of > > objects\pack\pack-*.idx/pack are also different). > > > > (all the commits are the same in both and all my data is also the same > > and 'fast-export --all' yields the same result) > > > > I'd like to know what might have caused this nondeterminism and if > > there is something to do to prevent that. > > You can get nondeterminism because the push to each repository happens > independently and delta compression is multithreaded. You can therefore > compute different packs on push and get different packs in the result. > > You could try to avoid it by disabling threading for pushes, but that > has to be done on each client that pushes to them. In general, this is > not worth worrying about as long as the data is intact (that is, it > passes git fsck) and the refs are identical. It is also not especially > easy to avoid, since determinism of pack files is not considered a goal > of Git. > > Maybe if you tell us a little more about your reason for wanting > bit-for-bit identical replicas we can provide some assistance in helping > you achieve your goals. > -- > brian m. carlson: Houston, Texas, US > OpenPGP: https://keybase.io/bk2204
