@matheusbsbs / matheus-bagliano / commits / de3a864114

config: set pack.useSparse=true by default

The pack.useSparse config option was introduced by 3d036eb0 (pack-objects: create pack.useSparse setting, 2019-01-19) and was first available in v2.21.0. When enabled, the pack-objects process during 'git push' will use a sparse tree walk when deciding which trees and blobs to send to the remote. The algorithm was introduced by d5d2e93 (revision: implement sparse algorithm, 2019-01-16) and has been in production use by VFS for Git since around that time. The features.experimental config option also enabled pack.useSparse, so hopefully that has also increased exposure. It is worth noting that pack.useSparse has a possibility of sending more objects across a push, but requires a special arrangement of exact _copies_ across directories. There is a test in t5322-pack-objects-sparse.sh that demonstrates this possibility. This test uses the --sparse option to "git pack-objects" but we can make it implied by the config value to demonstrate that the default value has changed. While updating that test, I noticed that the documentation did not include an option for --no-sparse, which is now more important than it was before. Since the downside is unlikely but the upside is significant, set the default value of pack.useSparse to true. Remove it from the set of options implied by features.experimental. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Derrick Stolee committed Mar 20, 2020 at 12:38 UTC de3a864114291632c05e67bec4a316257c7ff97d

5 files changed +12 -10

Documentation/config/feature.txt

-3

index 875f8c8a66..4e3a5c0ceb 100644 --- a/Documentation/config/feature.txt +++ b/Documentation/config/feature.txt @@ -12,9 +12,6 @@ feature.experimental:: setting if you are interested in providing feedback on experimental features. The new default values are: + -* `pack.useSparse=true` uses a new algorithm when constructing a pack-file -which can improve `git push` performance in repos with many files. -+ * `fetch.negotiationAlgorithm=skipping` may improve fetch negotiation times by skipping more commits at a time, reducing the number of round trips. +

Documentation/config/pack.txt

+2 -2

index 0dac580581..837f1b1679 100644 --- a/Documentation/config/pack.txt +++ b/Documentation/config/pack.txt @@ -119,8 +119,8 @@ pack.useSparse:: objects. This can have significant performance benefits when computing a pack to send a small change. However, it is possible that extra objects are added to the pack-file if the included - commits contain certain types of direct renames. Default is `false` - unless `feature.experimental` is enabled. + commits contain certain types of direct renames. Default is + `true`. pack.writeBitmaps (deprecated):: This is a deprecated synonym for `repack.writeBitmaps`.

Documentation/git-pack-objects.txt

+6 -3

index fecdf2600c..eaa2f2a404 100644 --- a/Documentation/git-pack-objects.txt +++ b/Documentation/git-pack-objects.txt @@ -14,7 +14,7 @@ SYNOPSIS [--local] [--incremental] [--window=<n>] [--depth=<n>] [--revs [--unpacked | --all]] [--keep-pack=<pack-name>] [--stdout [--filter=<filter-spec>] | base-name] - [--shallow] [--keep-true-parents] [--sparse] < object-list + [--shallow] [--keep-true-parents] [--[no-]sparse] < object-list DESCRIPTION @@ -196,14 +196,16 @@ depth is 4095. Add --no-reuse-object if you want to force a uniform compression level on all data no matter the source. ---sparse:: - Use the "sparse" algorithm to determine which objects to include in +--[no-]sparse:: + Toggle the "sparse" algorithm to determine which objects to include in the pack, when combined with the "--revs" option. This algorithm only walks trees that appear in paths that introduce new objects. This can have significant performance benefits when computing a pack to send a small change. However, it is possible that extra objects are added to the pack-file if the included commits contain - certain types of direct renames. + certain types of direct renames. If this option is not included, + it defaults to the value of `pack.useSparse`, which is true unless + otherwise specified. --thin:: Create a "thin" pack by omitting the common objects between a

repo-settings.c

+2 -1

index a703e407a3..dc6817daa9 100644 --- a/repo-settings.c +++ b/repo-settings.c @@ -45,6 +45,8 @@ void prepare_repo_settings(struct repository *r) if (!repo_config_get_bool(r, "pack.usesparse", &value)) r->settings.pack_use_sparse = value; + UPDATE_DEFAULT_BOOL(r->settings.pack_use_sparse, 1); + if (!repo_config_get_bool(r, "feature.manyfiles", &value) && value) { UPDATE_DEFAULT_BOOL(r->settings.index_version, 4); UPDATE_DEFAULT_BOOL(r->settings.core_untracked_cache, UNTRACKED_CACHE_WRITE); @@ -52,7 +54,6 @@ void prepare_repo_settings(struct repository *r) if (!repo_config_get_bool(r, "fetch.writecommitgraph", &value)) r->settings.fetch_write_commit_graph = value; if (!repo_config_get_bool(r, "feature.experimental", &value) && value) { - UPDATE_DEFAULT_BOOL(r->settings.pack_use_sparse, 1); UPDATE_DEFAULT_BOOL(r->settings.fetch_negotiation_algorithm, FETCH_NEGOTIATION_SKIPPING); UPDATE_DEFAULT_BOOL(r->settings.fetch_write_commit_graph, 1); }

t/t5322-pack-objects-sparse.sh

+2 -1

index 7124b5581a..6e5d6bdb0a 100755 --- a/t/t5322-pack-objects-sparse.sh +++ b/t/t5322-pack-objects-sparse.sh @@ -105,6 +105,7 @@ test_expect_success 'non-sparse pack-objects' ' test_cmp required_objects.txt nonsparse_required_objects.txt ' +# --sparse is enabled by default by pack.useSparse test_expect_success 'sparse pack-objects' ' git rev-parse \ topic1 \ @@ -112,7 +113,7 @@ test_expect_success 'sparse pack-objects' ' topic1:f3 \ topic1:f3/f4 \ topic1:f3/f4/data.txt | sort >expect_sparse_objects.txt && - git pack-objects --stdout --revs --sparse <packinput.txt >sparse.pack && + git pack-objects --stdout --revs <packinput.txt >sparse.pack && git index-pack -o sparse.idx sparse.pack && git show-index <sparse.idx | awk "{print \$2}" >sparse_objects.txt && test_cmp expect_sparse_objects.txt sparse_objects.txt