Re: Performance issue of 'git branch'

[Linus Torvalds <torvalds@linux-foundation.org>]

On Wed, 22 Jul 2009, Linus Torvalds wrote:
> 
> Ooh yes. That would do it. It's going to peel and look up every single ref 
> it finds, so it's going to look up _hundreds_ of objects (all the tags, 
> all the commits they point to, etc etc). Even if it then only shows a 
> couple of branches.
> 
> Junio, any ideas?

I had one of my own.

Does this fix it?

It uses the "raw" version of 'for_each_ref()' (which doesn't verify that 
the ref is valid), and then does the "type verification" before it starts 
doing any gentle commit lookup.

That should hopefully mean that it no longer does tons of object lookups 
on refs that it's not actually interested in. 

		Linus

---
 builtin-branch.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/builtin-branch.c b/builtin-branch.c
index 5687d60..54a89ff 100644
--- a/builtin-branch.c
+++ b/builtin-branch.c
@@ -240,6 +240,10 @@ static int append_ref(const char *refname, const unsigned char *sha1, int flags,
 	if (ARRAY_SIZE(ref_kind) <= i)
 		return 0;
 
+	/* Don't add types the caller doesn't want */
+	if ((kind & ref_list->kinds) == 0)
+		return 0;
+
 	commit = lookup_commit_reference_gently(sha1, 1);
 	if (!commit)
 		return error("branch '%s' does not point at a commit", refname);
@@ -248,10 +252,6 @@ static int append_ref(const char *refname, const unsigned char *sha1, int flags,
 	if (!is_descendant_of(commit, ref_list->with_commit))
 		return 0;
 
-	/* Don't add types the caller doesn't want */
-	if ((kind & ref_list->kinds) == 0)
-		return 0;
-
 	if (merge_filter != NO_FILTER)
 		add_pending_object(&ref_list->revs,
 				   (struct object *)commit, refname);
@@ -426,7 +426,7 @@ static void print_ref_list(int kinds, int detached, int verbose, int abbrev, str
 	ref_list.with_commit = with_commit;
 	if (merge_filter != NO_FILTER)
 		init_revisions(&ref_list.revs, NULL);
-	for_each_ref(append_ref, &ref_list);
+	for_each_rawref(append_ref, &ref_list);
 	if (merge_filter != NO_FILTER) {
 		struct commit *filter;
 		filter = lookup_commit_reference_gently(merge_filter_ref, 0);