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Diffstat (limited to 'doc/development/git_object_deduplication.md')
| -rw-r--r-- | doc/development/git_object_deduplication.md | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/doc/development/git_object_deduplication.md b/doc/development/git_object_deduplication.md index 6014ccbfb39..e98ebe5efe1 100644 --- a/doc/development/git_object_deduplication.md +++ b/doc/development/git_object_deduplication.md @@ -23,15 +23,17 @@ At the Git level, we achieve deduplication by using Git alternates is a mechanism that lets a repository borrow objects from another repository on the same machine. -If we want repository A to borrow from repository B, we first write a -path that resolves to `B.git/objects` in the special file -`A.git/objects/info/alternates`. This establishes the alternates link. -Next, we must perform a Git repack in A. After the repack, any objects -that are duplicated between A and B are deleted from A. Repository -A is now no longer self-contained, but it still has its own refs and -configuration. Objects in A that are not in B remain in A. For this -to work, it is of course critical that **no objects ever get deleted from -B** because A might need them. +To make repository A borrow from repository B: + +1. Establish the alternates link in the special file `A.git/objects/info/alternates` + by writing a path that resolves to `B.git/objects`. +1. In repository A, run `git repack` to remove all objects in repository A that + also exist in repository B. + +After the repack, repository A is no longer self-contained, but still contains its +own refs and configuration. Objects in A that are not in B remain in A. For this +configuration to work, **objects must not be deleted from repository B** because +repository A might need them. WARNING: Do not run `git prune` or `git gc` in object pool repositories, which are |