From: Jeff King <peff@peff.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>,
git@vger.kernel.org,
Johannes Schindelin <johannes.schindelin@gmx.de>
Subject: Re: [PATCH 4/4] get_oid(): when an object was not found, try harder
Date: Thu, 14 Mar 2019 14:55:57 -0400 [thread overview]
Message-ID: <20190314185556.GA26250@sigill.intra.peff.net> (raw)
In-Reply-To: <xmqqzhpy9k40.fsf@gitster-ct.c.googlers.com>
On Thu, Mar 14, 2019 at 01:05:03PM +0900, Junio C Hamano wrote:
> Jeff King <peff@peff.net> writes:
>
> > I'm not sure it's really worth addressing (just because I don't think
> > there's a good way to do it that isn't expensive).
>
> I do not think so, either. Not at this layer, anyway.
>
> If a "-x" command newly created an object whose prefix makes it
> ambiguous against an existing object, we would not notice, unless we
> refresh the loose object cache, that we now have two objects that
> share the prefix. And we will find an object (the older one) with
> the prefix in the stale cache without hitting "oh we do not find it,
> let's retry" codepath. So to solve both sides of the coin, we'd
> need invalidation either way, which obviously defeats the whole
> caching concept, doesn't it?
Right, that was the conclusion I came to. You cannot solve it in all
cases without checking whether new objects have appeared for every
lookup. I think that could be as cheap as a stat() on the pack
directory and one on the appropriate loose directory, but I suspect even
that might be measurably slower.
-Peff
next prev parent reply other threads:[~2019-03-14 18:57 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-13 10:16 [PATCH 0/4] get_oid: cope with a possibly stale loose object cache Johannes Schindelin via GitGitGadget
2019-03-13 10:16 ` [PATCH 1/4] rebase -i: demonstrate obscure loose object cache bug Johannes Schindelin via GitGitGadget
2019-03-13 16:11 ` Ævar Arnfjörð Bjarmason
2019-03-13 16:35 ` Jeff King
2019-03-13 16:53 ` Jeff King
2019-03-13 22:40 ` Johannes Schindelin
2019-03-14 0:07 ` Jeff King
2019-03-13 22:27 ` Johannes Schindelin
2019-03-14 0:05 ` Jeff King
2019-03-14 6:40 ` Johannes Sixt
2019-03-14 13:06 ` Johannes Schindelin
2019-03-14 1:12 ` Junio C Hamano
2019-03-14 12:44 ` Johannes Schindelin
2019-03-13 10:16 ` [PATCH 2/4] sequencer: improve error message when an OID could not be parsed Johannes Schindelin via GitGitGadget
2019-03-14 1:14 ` Junio C Hamano
2019-03-13 10:16 ` [PATCH 3/4] sequencer: move stale comment into correct location Johannes Schindelin via GitGitGadget
2019-03-13 10:16 ` [PATCH 4/4] get_oid(): when an object was not found, try harder Johannes Schindelin via GitGitGadget
2019-03-14 1:29 ` Junio C Hamano
2019-03-14 2:22 ` Jeff King
2019-03-14 2:40 ` Jeff King
2019-03-14 4:05 ` Junio C Hamano
2019-03-14 18:55 ` Jeff King [this message]
2019-03-14 3:49 ` Junio C Hamano
2019-03-14 13:17 ` Johannes Schindelin
2019-03-14 18:57 ` Jeff King
2019-03-14 19:55 ` Johannes Schindelin
2019-03-13 15:33 ` [PATCH 0/4] get_oid: cope with a possibly stale loose object cache Jeff King
2019-03-14 15:33 ` [PATCH v2 0/4] get_short_oid: " Johannes Schindelin via GitGitGadget
2019-03-14 15:33 ` [PATCH v2 1/4] rebase -i: demonstrate obscure loose object cache bug Johannes Schindelin via GitGitGadget
2019-03-14 15:33 ` [PATCH v2 2/4] sequencer: improve error message when an OID could not be parsed Johannes Schindelin via GitGitGadget
2019-03-14 15:33 ` [PATCH v2 3/4] sequencer: move stale comment into correct location Johannes Schindelin via GitGitGadget
2019-03-14 15:33 ` [PATCH v2 4/4] get_oid(): when an object was not found, try harder Johannes Schindelin via GitGitGadget
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