path: root/connected.c
diff options
authorJeff King <>2019-07-01 13:18:15 (GMT)
committerJunio C Hamano <>2019-07-01 17:11:09 (GMT)
commit39b44ba771a315602fd1fdca2e12dfc31ef9c613 (patch)
tree7ed94c7254550b396a8e4895aa1d2e8c1499d263 /connected.c
parent709dfa69908c9448db91a9bcc96941549be6421e (diff)
check_everything_connected: assume alternate ref tips are valid
When we receive a remote ref update to sha1 "X", we want to check that we have all of the objects needed by "X". We can assume that our repository is not currently corrupted, and therefore if we have a ref pointing at "Y", we have all of its objects. So we can stop our traversal from "X" as soon as we hit "Y". If we make the same non-corruption assumption about any repositories we use to store alternates, then we can also use their ref tips to shorten the traversal. This is especially useful when cloning with "--reference", as we otherwise do not have any local refs to check against, and have to traverse the whole history, even though the other side may have sent us few or no objects. Here are results for the included perf test (which shows off more or less the maximal savings, getting one new commit and sharing the whole history): Test HEAD^ HEAD -------------------------------------------------------------------- [on git.git] 5600.3: clone --reference 2.94(2.86+0.08) 0.09(0.08+0.01) -96.9% [on linux.git] 5600.3: clone --reference 45.74(45.34+0.41) 0.36(0.30+0.08) -99.2% Signed-off-by: Jeff King <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'connected.c')
1 files changed, 1 insertions, 0 deletions
diff --git a/connected.c b/connected.c
index 1ab481f..cd9b324 100644
--- a/connected.c
+++ b/connected.c
@@ -80,6 +80,7 @@ int check_connected(oid_iterate_fn fn, void *cb_data,
argv_array_push(&rev_list.args, "--all");
argv_array_push(&rev_list.args, "--quiet");
+ argv_array_push(&rev_list.args, "--alternate-refs");
if (opt->progress)
argv_array_pushf(&rev_list.args, "--progress=%s",
_("Checking connectivity"));