From 6fb9195f6c6df047949efcdb8a1fb9eaed0c925e Mon Sep 17 00:00:00 2001 From: Jeff King Date: Tue, 8 Jun 2021 03:24:48 -0400 Subject: [PATCH] doc: warn people against --max-pack-size This option is almost never a good idea, as the resulting repository is larger and slower (see the new explanations in the docs). I outlined the potential problems. We could go further and make the option harder to find (or at least, make the command-line option descriptions a much more terse "you probably don't want this; see pack.packsizeLimit for details"). But this seems like a minimal change that may prevent people from thinking it's more useful than it is. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- Documentation/config/pack.txt | 23 +++++++++++++++++------ Documentation/git-pack-objects.txt | 6 +++--- Documentation/git-repack.txt | 4 +++- 3 files changed, 23 insertions(+), 10 deletions(-) diff --git a/Documentation/config/pack.txt b/Documentation/config/pack.txt index 3da4ea98e2..10c778a942 100644 --- a/Documentation/config/pack.txt +++ b/Documentation/config/pack.txt @@ -99,12 +99,23 @@ pack.packSizeLimit:: packing to a file when repacking, i.e. the git:// protocol is unaffected. It can be overridden by the `--max-pack-size` option of linkgit:git-repack[1]. Reaching this limit results - in the creation of multiple packfiles; which in turn prevents - bitmaps from being created. - The minimum size allowed is limited to 1 MiB. - The default is unlimited. - Common unit suffixes of 'k', 'm', or 'g' are - supported. + in the creation of multiple packfiles. ++ +Note that this option is rarely useful, and may result in a larger total +on-disk size (because Git will not store deltas between packs), as well +as worse runtime performance (object lookup within multiple packs is +slower than a single pack, and optimizations like reachability bitmaps +cannot cope with multiple packs). ++ +If you need to actively run Git using smaller packfiles (e.g., because your +filesystem does not support large files), this option may help. But if +your goal is to transmit a packfile over a medium that supports limited +sizes (e.g., removable media that cannot store the whole repository), +you are likely better off creating a single large packfile and splitting +it using a generic multi-volume archive tool (e.g., Unix `split`). ++ +The minimum size allowed is limited to 1 MiB. The default is unlimited. +Common unit suffixes of 'k', 'm', or 'g' are supported. pack.useBitmaps:: When true, git will use pack bitmaps (if available) when packing diff --git a/Documentation/git-pack-objects.txt b/Documentation/git-pack-objects.txt index f85cb7ea93..c20b978510 100644 --- a/Documentation/git-pack-objects.txt +++ b/Documentation/git-pack-objects.txt @@ -118,10 +118,10 @@ depth is 4095. into multiple independent packfiles, each not larger than the given size. The size can be suffixed with "k", "m", or "g". The minimum size allowed is limited to 1 MiB. - This option - prevents the creation of a bitmap index. The default is unlimited, unless the config variable - `pack.packSizeLimit` is set. + `pack.packSizeLimit` is set. Note that this option may result in + a larger and slower repository; see the discussion in + `pack.packSizeLimit`. --honor-pack-keep:: This flag causes an object already in a local pack that diff --git a/Documentation/git-repack.txt b/Documentation/git-repack.txt index fbd4b4ae06..7bb797cbe8 100644 --- a/Documentation/git-repack.txt +++ b/Documentation/git-repack.txt @@ -121,7 +121,9 @@ depth is 4095. If specified, multiple packfiles may be created, which also prevents the creation of a bitmap index. The default is unlimited, unless the config variable - `pack.packSizeLimit` is set. + `pack.packSizeLimit` is set. Note that this option may result in + a larger and slower repository; see the discussion in + `pack.packSizeLimit`. -b:: --write-bitmap-index::