From: Nguyen Thai Ngoc Duy <pclouds@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Thomas Gummerer <t.gummerer@gmail.com>,
git@vger.kernel.org, trast@student.ethz.ch, mhagger@alum.mit.edu,
robin.rosenberg@dewire.com
Subject: Re: [PATCH/RFC v3 01/13] Move index v2 specific functions to their own file
Date: Fri, 10 Aug 2012 09:23:07 +0700 [thread overview]
Message-ID: <CACsJy8ChnS4cE3YnQQA8YQ5ebCA06QBXxEB7Oqhv4z_1y9Wc8w@mail.gmail.com> (raw)
In-Reply-To: <7v7gt7mwo3.fsf@alter.siamese.dyndns.org>
On Fri, Aug 10, 2012 at 7:13 AM, Junio C Hamano <gitster@pobox.com> wrote:
> By the way, you can only detect such inconsistency when you are
> lucky enough that you catch the other person in the middle of
> writing.
>
> If the index you are looking at holds a large tree with very many
> paths, it is possible that there are two large directories, and
> after you read all entries from one, the other process starts
> modifying the paths in that directory, without you ever finding it
> out. If the goal of the topic is to make the index work better in
> projects with large trees, it may be wise to think about locking the
> whole thing, so that you do not have to rely on the per-entry crc
> and you being lucky to detect such a race. The per-entry crc, as
> far as I understand, may have been introduced primarily to detect
> on-disk data corruption; it is not a suitable mechanism to detect
> conflicting accesses.
So we acquire the lock just before we need to write, or at the time we
open for reading?
--
Duy
next prev parent reply other threads:[~2012-08-10 2:23 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-08 11:17 [PATCH/RFC v3 0/13] Introduce index file format version 5 Thomas Gummerer
2012-08-08 11:17 ` [PATCH/RFC v3 01/13] Move index v2 specific functions to their own file Thomas Gummerer
2012-08-08 12:04 ` Nguyen Thai Ngoc Duy
2012-08-08 19:21 ` Thomas Gummerer
2012-08-09 22:02 ` Junio C Hamano
2012-08-09 22:54 ` Thomas Gummerer
2012-08-10 0:13 ` Junio C Hamano
2012-08-10 2:23 ` Nguyen Thai Ngoc Duy [this message]
2012-08-10 14:24 ` Thomas Rast
2012-08-10 14:58 ` Junio C Hamano
2012-08-10 15:40 ` Thomas Gummerer
2012-08-08 11:17 ` [PATCH/RFC v3 02/13] t2104: Don't fail for index versions other than [23] Thomas Gummerer
2012-08-08 11:17 ` [PATCH/RFC v3 03/13] t3700: Avoid interfering with the racy code Thomas Gummerer
2012-08-08 11:17 ` [PATCH/RFC v3 04/13] Add documentation of the index-v5 file format Thomas Gummerer
2012-08-09 22:41 ` Junio C Hamano
2012-08-09 23:10 ` Thomas Gummerer
2012-08-09 23:13 ` Junio C Hamano
2012-08-08 11:17 ` [PATCH/RFC v3 05/13] Make in-memory format aware of stat_crc Thomas Gummerer
2012-08-08 11:17 ` [PATCH/RFC v3 06/13] Read index-v5 Thomas Gummerer
2012-08-08 12:05 ` Nguyen Thai Ngoc Duy
2012-08-08 12:18 ` Johannes Sixt
2012-08-08 17:05 ` Junio C Hamano
2012-08-08 19:29 ` Thomas Gummerer
2012-08-08 11:17 ` [PATCH/RFC v3 07/13] Read resolve-undo data Thomas Gummerer
2012-08-09 22:51 ` Junio C Hamano
2012-08-09 23:23 ` Thomas Gummerer
2012-08-10 0:02 ` Junio C Hamano
2012-08-10 9:27 ` Thomas Gummerer
2012-08-08 11:17 ` [PATCH/RFC v3 08/13] Read cache-tree in index-v5 Thomas Gummerer
2012-08-08 11:17 ` [PATCH/RFC v3 09/13] Write index-v5 Thomas Gummerer
2012-08-08 11:17 ` [PATCH/RFC v3 10/13] Write index-v5 cache-tree data Thomas Gummerer
2012-08-08 11:17 ` [PATCH/RFC v3 11/13] Write resolve-undo data for index-v5 Thomas Gummerer
2012-08-08 11:18 ` [PATCH/RFC v3 12/13] update-index.c: always rewrite the index when index-version is given Thomas Gummerer
2012-08-08 11:18 ` [PATCH/RFC v3 13/13] p0002-index.sh: add perf test for the index formats Thomas Gummerer
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