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From: Vegard Nossum <vegard.nossum@oracle.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: git@vger.kernel.org,
	"Quentin Casasnovas" <quentin.casasnovas@oracle.com>,
	"Shawn Pearce" <spearce@spearce.org>, "Jeff King" <peff@peff.net>,
	"Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>
Subject: Re: Huge performance bottleneck reading packs
Date: Thu, 13 Oct 2016 09:17:34 +0200	[thread overview]
Message-ID: <1d5dd36b-7a9e-ac00-352a-d71e0e277002@oracle.com> (raw)
In-Reply-To: <xmqqpon5190s.fsf@gitster.mtv.corp.google.com>

On 10/13/2016 12:45 AM, Junio C Hamano wrote:
 > Vegard Nossum <vegard.nossum@oracle.com> writes:
 >
 >> A closer inspection reveals the problem to really be that this is an
 >> extremely hot path with more than -- holy cow -- 4,106,756,451
 >> iterations on the 'packed_git' list for a single 'git fetch' on my
 >> repository. I'm guessing the patch above just made the inner loop
 >> ever so slightly slower.
 >
 > Very plausible, and this ...
 >
 >> My .git/objects/pack/ has ~2088 files (1042 idx files, 1042 pack files,
 >> and 4 tmp_pack_* files).
 >
 > ... may explain why nobody else has seen a difference.
 >
 > Is there a reason why your repository has that many pack files?  Is
 > automatic GC not working for some reason?

Oops. I disabled gc a while ago; one reason I did that is that it takes
a long time to run and it has a tendency to kick in at the worst time. I
guess I should really put it in cron then.

I'm not sure if this is related, but I also had a problem with GitPython
and large pack files in the past (" ValueError: Couldn't obtain fanout
table or warning: packfile ./objects/pack/....pack cannot be accessed")
and I have pack.packSizeLimit set to 512m to fix that.
Although the whole repo is 17G so I guess it shouldn't be necessary to
have that many pack files.

Will try Jeff's patch, then a gc. Thanks!


Vegard

  reply	other threads:[~2016-10-13  9:57 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-12 22:30 Huge performance bottleneck reading packs Vegard Nossum
2016-10-12 22:45 ` Junio C Hamano
2016-10-13  7:17   ` Vegard Nossum [this message]
2016-10-13 14:50     ` Jeff King
2016-10-12 23:01 ` Jeff King
2016-10-12 23:18   ` Jeff King
2016-10-12 23:47     ` Jeff King
2016-10-13  9:04       ` Vegard Nossum
2016-10-14  9:35         ` Jakub Narębski
2016-10-13  7:20   ` Vegard Nossum
2016-10-13 15:26     ` Jeff King
2016-10-13 16:53       ` [PATCH] fetch: use "quick" has_sha1_file for tag following Jeff King
2016-10-13 17:04         ` Jeff King
2016-10-13 20:06           ` Jeff King
2016-10-14 17:39             ` Junio C Hamano
2016-10-14 18:59               ` Jeff King
2016-10-17 17:30                 ` Junio C Hamano
2016-10-18 10:28                   ` Jeff King
2016-10-13 18:18       ` Huge performance bottleneck reading packs Vegard Nossum
2016-10-13 20:43         ` Jeff King
2016-10-14  6:55           ` Vegard Nossum
2016-10-14 19:00             ` Jeff King

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