From 926f1dd95486b596de1f6b8e108053a870da0e18 Mon Sep 17 00:00:00 2001 From: Jeff King Date: Fri, 6 Jan 2012 14:17:40 -0500 Subject: [PATCH] upload-pack: avoid parsing objects during ref advertisement When we advertise a ref, the first thing we do is parse the pointed-to object. This gives us two things: 1. a "struct object" we can use to store flags 2. the type of the object, so we know whether we need to dereference it as a tag Instead, we can just use lookup_unknown_object to get an object struct, and then fill in just the type field using sha1_object_info (which, in the case of packed files, can find the information without actually inflating the object data). This can save time if you have a large number of refs, and the client isn't actually going to request those refs (e.g., because most of them are already up-to-date). The downside is that we are no longer verifying objects that we advertise by fully parsing them (however, we do still know we actually have them, because sha1_object_info must find them to get the type). While we might fail to detect a corrupt object here, if the client actually fetches the object, we will parse (and verify) it then. On a repository with 120K refs, the advertisement portion of upload-pack goes from ~3.4s to 3.2s (the failure to speed up more is largely due to the fact that most of these refs are tags, which need dereferenced to find the tag destination anyway). Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- upload-pack.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/upload-pack.c b/upload-pack.c index 6f36f6255..65cb0ff0f 100644 --- a/upload-pack.c +++ b/upload-pack.c @@ -720,11 +720,14 @@ static int send_ref(const char *refname, const unsigned char *sha1, int flag, vo static const char *capabilities = "multi_ack thin-pack side-band" " side-band-64k ofs-delta shallow no-progress" " include-tag multi_ack_detailed"; - struct object *o = parse_object(sha1); + struct object *o = lookup_unknown_object(sha1); const char *refname_nons = strip_namespace(refname); - if (!o) - die("git upload-pack: cannot find object %s:", sha1_to_hex(sha1)); + if (o->type == OBJ_NONE) { + o->type = sha1_object_info(sha1, NULL); + if (o->type < 0) + die("git upload-pack: cannot find object %s:", sha1_to_hex(sha1)); + } if (capabilities) packet_write(1, "%s %s%c%s%s\n", sha1_to_hex(sha1), refname_nons, @@ -738,6 +741,7 @@ static int send_ref(const char *refname, const unsigned char *sha1, int flag, vo nr_our_refs++; } if (o->type == OBJ_TAG) { + o = parse_object(o->sha1); o = deref_tag(o, refname, 0); if (o) packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname_nons); -- 2.26.2