git@vger.kernel.org list mirror (unofficial, one of many)
 help / color / mirror / Atom feed
From: Jonathan Tan <jonathantanmy@google.com>
To: git@vger.kernel.org
Cc: Jonathan Tan <jonathantanmy@google.com>, gitster@pobox.com
Subject: [PATCH v2] send-pack: never fetch when checking exclusions
Date: Tue,  8 Oct 2019 11:37:39 -0700
Message-ID: <20191008183739.194714-1-jonathantanmy@google.com> (raw)
In-Reply-To: <xmqqzhibnahi.fsf@gitster-ct.c.googlers.com>

When building the packfile to be sent, send_pack() is given a list of
remote refs to be used as exclusions. For each ref, it first checks if
the ref exists locally, and if it does, passes it with a "^" prefix to
pack-objects. However, in a partial clone, the check may trigger a lazy
fetch.

The additional commit ancestry information obtained during such fetches
may show that certain objects that would have been sent are already
known to the server, resulting in a smaller pack being sent. But this is
at the cost of fetching from many possibly unrelated refs, and the lazy
fetches do not help at all in the typical case where the client is
up-to-date with the upstream of the branch being pushed.

Ensure that these lazy fetches do not occur.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
---
> For example, would this change mean that the resulting pack may
> include stuff that are reachable from the (missing) negative objects
> that would not otherwise have to be sent if these objects were
> available (or made available by the lazy fetching), and we are
> making a trade-off to send possibly more in order for not fetching?
> Have we laid enough on the table to help readers if such a trade-off
> (if we are making one, that is) strikes the right balance?

Thanks for your comments. I've expanded the commit message.
---
 send-pack.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/send-pack.c b/send-pack.c
index 6dc16c3211..34c77cbb1a 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -40,7 +40,8 @@ int option_parse_push_signed(const struct option *opt,
 
 static void feed_object(const struct object_id *oid, FILE *fh, int negative)
 {
-	if (negative && !has_object_file(oid))
+	if (negative &&
+	    !has_object_file_with_flags(oid, OBJECT_INFO_SKIP_FETCH_OBJECT))
 		return;
 
 	if (negative)
-- 
2.23.0.581.g78d2f28ef7-goog


  reply	other threads:[~2019-10-08 18:37 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-07 21:38 [PATCH] " Jonathan Tan
2019-10-08  4:10 ` Junio C Hamano
2019-10-08 18:37   ` Jonathan Tan [this message]
2019-10-11  6:12     ` [PATCH v2] " Jeff King
2019-10-11 12:31       ` Derrick Stolee
2019-10-11 16:15         ` Jeff King
2019-10-11 22:08           ` Jonathan Tan
2019-10-17  6:10             ` Jeff King
2019-10-12  0:47           ` Junio C Hamano

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: http://vger.kernel.org/majordomo-info.html

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191008183739.194714-1-jonathantanmy@google.com \
    --to=jonathantanmy@google.com \
    --cc=git@vger.kernel.org \
    --cc=gitster@pobox.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

git@vger.kernel.org list mirror (unofficial, one of many)

This inbox may be cloned and mirrored by anyone:

	git clone --mirror https://public-inbox.org/git
	git clone --mirror http://ou63pmih66umazou.onion/git
	git clone --mirror http://czquwvybam4bgbro.onion/git
	git clone --mirror http://hjrcffqmbrq6wope.onion/git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V1 git git/ https://public-inbox.org/git \
		git@vger.kernel.org
	public-inbox-index git

Example config snippet for mirrors.
Newsgroups are available over NNTP:
	nntp://news.public-inbox.org/inbox.comp.version-control.git
	nntp://ou63pmih66umazou.onion/inbox.comp.version-control.git
	nntp://czquwvybam4bgbro.onion/inbox.comp.version-control.git
	nntp://hjrcffqmbrq6wope.onion/inbox.comp.version-control.git
	nntp://news.gmane.io/gmane.comp.version-control.git
 note: .onion URLs require Tor: https://www.torproject.org/

code repositories for the project(s) associated with this inbox:

	https://80x24.org/mirrors/git.git

AGPL code for this site: git clone https://public-inbox.org/public-inbox.git