From cf2dc1c238c6fd5f93c315a3045ccf95459701cd Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Wed, 7 Jul 2021 23:10:15 +0000 Subject: speed up alt_odb_usable() with many alternates With many alternates, the duplicate check in alt_odb_usable() wastes many cycles doing repeated fspathcmp() on every existing alternate. Use a khash to speed up lookups by odb->path. Since the kh_put_* API uses the supplied key without duplicating it, we also take advantage of it to replace both xstrdup() and strbuf_release() in link_alt_odb_entry() with strbuf_detach() to avoid the allocation and copy. In a test repository with 50K alternates and each of those 50K alternates having one alternate each (for a total of 100K total alternates); this speeds up lookup of a non-existent blob from over 16 minutes to roughly 2.7 seconds on my busy workstation. Note: all underlying git object directories were small and unpacked with only loose objects and no packs. Having to load packs increases times significantly. Signed-off-by: Eric Wong Signed-off-by: Junio C Hamano --- object.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'object.c') diff --git a/object.c b/object.c index 14188453c5..2b3c075a15 100644 --- a/object.c +++ b/object.c @@ -511,6 +511,8 @@ static void free_object_directories(struct raw_object_store *o) free_object_directory(o->odb); o->odb = next; } + kh_destroy_odb_path_map(o->odb_by_path); + o->odb_by_path = NULL; } void raw_object_store_clear(struct raw_object_store *o) -- cgit v1.2.3