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Diffstat (limited to 'Documentation/gitformat-pack.txt')
| -rw-r--r-- | Documentation/gitformat-pack.txt | 36 |
1 files changed, 1 insertions, 35 deletions
diff --git a/Documentation/gitformat-pack.txt b/Documentation/gitformat-pack.txt index 0c1be2dbe8..870e00f298 100644 --- a/Documentation/gitformat-pack.txt +++ b/Documentation/gitformat-pack.txt @@ -588,51 +588,17 @@ later on. It is linkgit:git-gc[1] that is typically responsible for removing expired unreachable objects. -=== Caution for mixed-version environments - -Repositories that have cruft packs in them will continue to work with any older -version of Git. Note, however, that previous versions of Git which do not -understand the `.mtimes` file will use the cruft pack's mtime as the mtime for -all of the objects in it. In other words, do not expect older (pre-cruft pack) -versions of Git to interpret or even read the contents of the `.mtimes` file. - -Note that having mixed versions of Git GC-ing the same repository can lead to -unreachable objects never being completely pruned. This can happen under the -following circumstances: - - - An older version of Git running GC explodes the contents of an existing - cruft pack loose, using the cruft pack's mtime. - - A newer version running GC collects those loose objects into a cruft pack, - where the .mtime file reflects the loose object's actual mtimes, but the - cruft pack mtime is "now". - -Repeating this process will lead to unreachable objects not getting pruned as a -result of repeatedly resetting the objects' mtimes to the present time. - -If you are GC-ing repositories in a mixed version environment, consider omitting -the `--cruft` option when using linkgit:git-repack[1] and linkgit:git-gc[1], and -setting the `gc.cruftPacks` configuration to "false" until all writers -understand cruft packs. - === Alternatives Notable alternatives to this design include: - - The location of the per-object mtime data, and - - Storing unreachable objects in multiple cruft packs. + - The location of the per-object mtime data. On the location of mtime data, a new auxiliary file tied to the pack was chosen to avoid complicating the `.idx` format. If the `.idx` format were ever to gain support for optional chunks of data, it may make sense to consolidate the `.mtimes` format into the `.idx` itself. -Storing unreachable objects among multiple cruft packs (e.g., creating a new -cruft pack during each repacking operation including only unreachable objects -which aren't already stored in an earlier cruft pack) is significantly more -complicated to construct, and so aren't pursued here. The obvious drawback to -the current implementation is that the entire cruft pack must be re-written from -scratch. - GIT --- Part of the linkgit:git[1] suite |