From: Derrick Stolee <derrickstolee@github.com>
To: "Jeff King" <peff@peff.net>, 程洋 <chengyang@xiaomi.com>
Cc: "git@vger.kernel.org" <git@vger.kernel.org>,
何浩 <hehao@xiaomi.com>, "Xin7 Ma 马鑫" <maxin7@xiaomi.com>,
石奉兵 <shifengbing@xiaomi.com>, 凡军辉 <fanjunhui@xiaomi.com>,
王汉基 <wanghanji@xiaomi.com>
Subject: Re: [PATCH 3/3] parse_object(): check commit-graph when skip_hash set
Date: Wed, 7 Sep 2022 10:46:55 -0400 [thread overview]
Message-ID: <60a47a3f-e4d5-2339-d79e-48e6a7d4a9f1@github.com> (raw)
In-Reply-To: <YxfScUATMQw9cB6m@coredump.intra.peff.net>
On 9/6/2022 7:06 PM, Jeff King wrote:
> If the caller told us that they don't care about us checking the object
> hash, then we're free to implement any optimizations that get us the
> parsed value more quickly. An obvious one is to check the commit graph
> before loading an object from disk. And in fact, both of the callers who
> pass in this flag are already doing so before they call parse_object()!
>
> So we can simplify those callers, as well as any possible future ones,
> by moving the logic into parse_object().
Nice!
> There are two subtle things to note in the diff, but neither has any
> impact in practice:
>
> - it seems least-surprising here to do the graph lookup on the
> git-replace'd oid, rather than the original. This is in theory a
> change of behavior from the earlier code, as neither caller did a
> replace lookup itself. But in practice it doesn't matter, as we
> disable the commit graph entirely if there are any replace refs.
I can confirm that this is the case.
> - the caller in get_reference() passes the skip_hash flag only if
> revs->verify_objects isn't set, whereas it would look in the commit
> graph unconditionally. In practice this should not matter as we
> should disable the commit graph entirely when using verify_objects
> (and that was done recently in another patch).
>
> So this should be a pure cleanup with no behavior change.
Excellent, thanks!
-Stolee
next prev parent reply other threads:[~2022-09-07 14:47 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-11 8:09 Partial-clone cause big performance impact on server 程洋
2022-08-11 17:22 ` Jonathan Tan
2022-08-13 7:55 ` 回复: [External Mail]Re: " 程洋
2022-08-13 11:41 ` 程洋
2022-08-15 5:16 ` ZheNing Hu
2022-08-15 13:15 ` 程洋
2022-08-12 12:21 ` Derrick Stolee
2022-08-14 6:48 ` Jeff King
2022-08-15 13:18 ` Derrick Stolee
2022-08-15 14:50 ` [External Mail]Re: " 程洋
2022-08-17 10:22 ` 程洋
2022-08-17 13:41 ` Derrick Stolee
2022-08-18 5:49 ` Jeff King
2022-09-01 6:53 ` 程洋
2022-09-01 16:19 ` Jeff King
2022-09-05 11:17 ` 程洋
2022-09-06 18:38 ` Jeff King
2022-09-06 22:58 ` [PATCH 0/3] speeding up on-demand fetch for blobs in partial clone Jeff King
2022-09-06 23:01 ` [PATCH 1/3] parse_object(): allow skipping hash check Jeff King
2022-09-07 14:15 ` Derrick Stolee
2022-09-07 20:44 ` Jeff King
2022-09-06 23:05 ` [PATCH 2/3] upload-pack: skip parse-object re-hashing of "want" objects Jeff King
2022-09-07 14:36 ` Derrick Stolee
2022-09-07 14:45 ` Derrick Stolee
2022-09-07 20:50 ` Jeff King
2022-09-07 19:26 ` Junio C Hamano
2022-09-07 20:36 ` Jeff King
2022-09-07 20:48 ` [BUG] t1800: Fails for error text comparison rsbecker
2022-09-07 21:55 ` Junio C Hamano
2022-09-07 22:23 ` rsbecker
2022-09-07 21:02 ` [PATCH 2/3] upload-pack: skip parse-object re-hashing of "want" objects Jeff King
2022-09-07 22:07 ` Junio C Hamano
2022-09-08 5:04 ` Jeff King
2022-09-08 16:41 ` Junio C Hamano
2022-09-06 23:06 ` [PATCH 3/3] parse_object(): check commit-graph when skip_hash set Jeff King
2022-09-07 14:46 ` Derrick Stolee [this message]
2022-09-07 19:31 ` Junio C Hamano
2022-09-08 10:39 ` [External Mail]Re: " 程洋
2022-09-08 18:42 ` Jeff King
2022-09-07 14:48 ` [PATCH 0/3] speeding up on-demand fetch for blobs in partial clone Derrick Stolee
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