git@vger.kernel.org mailing list mirror (one of many)
 help / color / mirror / code / Atom feed
From: wferi@niif.hu (Ferenc Wágner)
To: "SZEDER Gábor" <szeder.dev@gmail.com>
Cc: git@vger.kernel.org
Subject: Re: branch --contains / tag --merged inconsistency
Date: Sat, 28 Apr 2018 08:27:17 +0200	[thread overview]
Message-ID: <877eor6e2i.fsf@lant.ki.iif.hu> (raw)
In-Reply-To: <20180427160344.12724-1-szeder.dev@gmail.com> ("SZEDER Gábor"'s message of "Fri, 27 Apr 2018 18:03:44 +0200")

SZEDER Gábor <szeder.dev@gmail.com> writes:

> The commit pointed to by the tag Pacemaker-0.6.1 and its parent have a
> serious clock skew, i.e. they are a few months older than their parents:
> [...]
> (branch|tag|describe|...) (--contains|--merged) use the commit timestamp
> information as a heuristic to avoid traversing parts of the history,
> which makes these operations, especially on big histories, an order of
> magnitude or two faster.  Yeah, commit timestamps can't always be
> trusted, but skewed commits are rare, and skewed commits with this much
> skew are even rarer.

Szia Gábor,

Thank you very much for the explanation!  Good to know there's no
serious problem or misunderstanding here, but a conscious algorithmic
choice being fooled by clock skew.  I wonder if there's a way such clock
skew can appear without actual committer clocks being off by months...

> FWIW, much work is being done on a cached commit graph including commit
> generation numbers, which will solve this issue both correctly and more
> efficiently.  Perhaps it will already be included in the next release.

Wonderful news, thanks for sharing it!
-- 
Regards,
Feri

  reply	other threads:[~2018-04-28  6:27 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-27 14:30 branch --contains / tag --merged inconsistency Ferenc Wágner
2018-04-27 16:03 ` SZEDER Gábor
2018-04-28  6:27   ` Ferenc Wágner [this message]
2018-04-30 14:01   ` Derrick Stolee

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=877eor6e2i.fsf@lant.ki.iif.hu \
    --to=wferi@niif.hu \
    --cc=git@vger.kernel.org \
    --cc=szeder.dev@gmail.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
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this public inbox

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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).