The core.bigFileThreshold documentation has been largely unchanged
since 5eef828bc03 (fast-import: Stream very large blobs directly to
pack, 2010-02-01).
But since then this setting has been expanded to affect a lot more
than that description indicated. Most notably in how "git diff" treats
them, see 6bf3b813486 (diff --stat: mark any file larger than
core.bigfilethreshold binary, 2014-08-16).
In addition to that, numerous commands and APIs make use of a
streaming mode for files above this threshold.
So let's attempt to summarize 12 years of changes in behavior, which
can be seen with:
git log --oneline -Gbig_file_thre 5eef828bc03.. -- '*.c'
To do that turn this into a bullet-point list. The summary Han Xin
produced in [1] helped a lot, but is a bit too detailed for
documentation aimed at users. Let's instead summarize how
user-observable behavior differs, and generally describe how we tend
to stream these files in various commands.
1. https://lore.kernel.org/git/20220120112114.47618-5-chiyutianyi@xxxxxxxxx/
Helped-by: Han Xin <chiyutianyi@xxxxxxxxx>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx>
---
Documentation/config/core.txt | 33 ++++++++++++++++++++++++---------
1 file changed, 24 insertions(+), 9 deletions(-)
diff --git a/Documentation/config/core.txt b/Documentation/config/core.txt
index c04f62a54a1..b6a12218665 100644
--- a/Documentation/config/core.txt
+++ b/Documentation/config/core.txt
@@ -412,17 +412,32 @@ You probably do not need to adjust this value.
Common unit suffixes of 'k', 'm', or 'g' are supported.
core.bigFileThreshold::
- Files larger than this size are stored deflated, without
- attempting delta compression. Storing large files without
- delta compression avoids excessive memory usage, at the
- slight expense of increased disk usage. Additionally files
- larger than this size are always treated as binary.
+ The size of files considered "big", which as discussed below
+ changes the behavior of numerous git commands, as well as how
+ such files are stored within the repository. The default is
+ 512 MiB. Common unit suffixes of 'k', 'm', or 'g' are
+ supported.
+
-Default is 512 MiB on all platforms. This should be reasonable
-for most projects as source code and other text files can still
-be delta compressed, but larger binary media files won't be.
+Files above the configured limit will be:
+
-Common unit suffixes of 'k', 'm', or 'g' are supported.
+* Stored deflated, without attempting delta compression.
++
+The default limit is primarily set with this use-case in mind. With it
+most projects will have their source code and other text files delta
+compressed, but not larger binary media files.
++
+Storing large files without delta compression avoids excessive memory
+usage, at the slight expense of increased disk usage.
++
+* Will be treated as if though they were labeled "binary" (see
+ linkgit:gitattributes[5]). This means that e.g. linkgit:git-log[1]
+ and linkgit:git-diff[1] will not diffs for files above this limit.
++
+* Will be generally be streamed when written, which avoids excessive
+memory usage, at the cost of some fixed overhead. Commands that make
+use of this include linkgit:git-archive[1],
+linkgit:git-fast-import[1], linkgit:git-index-pack[1] and
+linkgit:git-fsck[1].
core.excludesFile::
Specifies the pathname to the file that contains patterns to
--
2.35.1.1438.g8874c8eeb35
