[PATCH 2/2] let pack-objects do the writing of unreachable objects as loose objects
- From
Nicolas Pitre <nico@cam.org>
- Date
- May 14, 2008, 05:33 UTC
- Message-ID
- <alpine.LFD.1.10.0805140132500.23581@xanadu.home>
Commit ccc1297226b184c40459e9d373cc9eebfb7bd898 changed the behavior of 'git repack -A' so unreachable objects are stored as loose objects. However it did so in a naive and inn efficient way by making packs about to be deleted inaccessible and feeding their content through 'git unpack-objects'. While this works, there are major flaws with this approach:
- It is unacceptably sloooooooooooooow.
In the Linux kernel repository with no actual unreachable objects, doing 'git repack -A -d' before:
real 2m33.220s user 2m21.675s sys 0m3.510s
And with this change:
real 0m36.849s user 0m24.365s sys 0m1.950s
For reference, here's the timing for 'git repack -a -d':
real 0m35.816s user 0m22.571s sys 0m2.011s
This is explained by the fact that 'git unpack-objects' was used to unpack _every_ objects even if (almost) 100% of them were thrown away.
- There is a black out period.
Between the removal of the .idx file for the redundant pack and the completion of its unpacking, the unreachable objects become completely unaccessible. This is not a big issue as we're talking about unreachable objects, but some consistency is always good.
- There is no way to easily set a sensible mtime for the newly created unreachable loose objects.
So, while having a command called "pack-objects" to perform object unpacking looks really odd, this is probably the best compromize to be able to solve the above issues in an efficient way.
Signed-off-by: Nicolas Pitre <nico@cam.org>
diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c index e20851e..f43eb67 100644 --- a/builtin-pack-objects.c +++ b/builtin-pack-objects.c @@ -28,7 +28,8 @@ git-pack-objects [{ -q | --progress | --all-progress }] \n\ [--window=N] [--window-memory=N] [--depth=N] \n\ [--no-reuse-delta] [--no-reuse-object] [--delta-base-offset] \n\ [--threads=N] [--non-empty] [--revs [--unpacked | --all]*] [--reflog] \n\ - [--stdout | base-name] [--include-tag] [--keep-unreachable] \n\ + [--stdout | base-name] [--include-tag] \n\ + [--keep-unreachable | --unpack-unreachable] \n\ [<ref-list | <object-list]"; struct object_entry { @@ -67,7 +68,7 @@ static uint32_t nr_objects, nr_alloc, nr_result, nr_written; static int non_empty; static int reuse_delta = 1, reuse_object = 1; -static int keep_unreachable, include_tag; +static int keep_unreachable, unpack_unreachable, include_tag; static int local; static int incremental; static int allow_ofs_delta; @@ -1946,6 +1947,32 @@ static void add_objects_in_unpacked_packs(struct rev_info *revs) free(in_pack.array); } +static void loosen_unused_packed_objects(struct rev_info *revs) +{ + struct packed_git *p; + uint32_t i; + const unsigned char *sha1; + + for (p = packed_git; p; p = p->next) { + for (i = 0; i < revs->num_ignore_packed; i++) { + if (matches_pack_name(p, revs->ignore_packed[i])) + break; + } + if (revs->num_ignore_packed <= i) + continue; + + if (open_pack_index(p)) + die("cannot open pack index"); + + for (i = 0; i < p->num_objects; i++) { + sha1 = nth_packed_object_sha1(p, i); + if (!locate_object_entry(sha1)) + if (force_object_loose(sha1, p->mtime)) + die("unable to force loose object"); + } + } +} + static void get_object_list(int ac, const char **av) { struct rev_info revs; @@ -1980,6 +2007,8 @@ static void get_object_list(int ac, const char **av) if (keep_unreachable) add_objects_in_unpacked_packs(&revs); + if (unpack_unreachable) + loosen_unused_packed_objects(&revs); } static int adjust_perm(const char *path, mode_t mode) @@ -2114,6 +2143,10 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix) keep_unreachable = 1; continue; } + if (!strcmp("--unpack-unreachable", arg)) { + unpack_unreachable = 1; + continue; + } if (!strcmp("--include-tag", arg)) { include_tag = 1; continue; @@ -2179,6 +2212,9 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix) if (!pack_to_stdout && thin) die("--thin cannot be used to build an indexable pack."); + if (keep_unreachable && unpack_unreachable) + die("--keep-unreachable and --unpack-unreachable are incompatible."); + #ifdef THREADED_DELTA_SEARCH if (!delta_search_threads) /* --threads=0 means autodetect */ delta_search_threads = online_cpus(); diff --git a/git-repack.sh b/git-repack.sh index 0aede89..10f735c 100755 --- a/git-repack.sh +++ b/git-repack.sh @@ -8,7 +8,7 @@ OPTIONS_SPEC="\ git-repack [options] -- a pack everything in a single pack -A same as -a, and keep unreachable objects too +A same as -a, and turn unreachable objects loose d remove redundant packs, and run git-prune-packed f pass --no-reuse-delta to git-pack-objects n do not run git-update-server-info @@ -23,7 +23,7 @@ max-pack-size= maximum size of each packfile SUBDIRECTORY_OK='Yes' . git-sh-setup -no_update_info= all_into_one= remove_redundant= keep_unreachable= +no_update_info= all_into_one= remove_redundant= unpack_unreachable= local= quiet= no_reuse= extra= while test $# != 0 do @@ -31,7 +31,7 @@ do -n) no_update_info=t ;; -a) all_into_one=t ;; -A) all_into_one=t - keep_unreachable=t ;; + unpack_unreachable=--unpack-unreachable ;; -d) remove_redundant=t ;; -q) quiet=-q ;; -f) no_reuse=--no-reuse-object ;; @@ -79,6 +79,9 @@ case ",$all_into_one," in if test -z "$args" then args='--unpacked --incremental' + elif test -n "$unpack_unreachable" + then + args="$args $unpack_unreachable" fi ;; esac @@ -128,18 +131,7 @@ then do case " $fullbases " in *" $e "*) ;; - *) - rm -f "$e.idx" "$e.keep" - if test -n "$keep_unreachable" && - test -f "$e.pack" - then - git unpack-objects < "$e.pack" || { - echo >&2 "Failed unpacking unreachable objects from redundant pack file $e.pack" - exit 1 - } - fi - rm -f "$e.pack" - ;; + *) rm -f "$e.pack" "$e.idx" "$e.keep" ;; esac done )