From: "Xing Xin" <bupt_xingxin@163.com>
To: "Karthik Nayak" <karthik.188@gmail.com>
Cc: "blanet via GitGitGadget" <gitgitgadget@gmail.com>,
git@vger.kernel.org, "Xing Xin" <xingxin.xx@bytedance.com>
Subject: Re:Re: [PATCH] bundle-uri: refresh packed_git if unbundle succeed
Date: Mon, 20 May 2024 18:19:53 +0800 (CST) [thread overview]
Message-ID: <59d5f488.ad90.18f9583cbc2.Coremail.bupt_xingxin@163.com> (raw)
In-Reply-To: <CAOLa=ZT=x6bmnvJO2KtbJvVOvt=4LH1RgU1NMJYpTgW2XXfGVg@mail.gmail.com>
At 2024-05-17 15:36:53, "Karthik Nayak" <karthik.188@gmail.com> wrote:
>"blanet via GitGitGadget" <gitgitgadget@gmail.com> writes:
>
>> From: Xing Xin <xingxin.xx@bytedance.com>>
>> When using the bundle-uri mechanism with a bundle list containing
>> multiple interrelated bundles, we encountered a bug where tips from
>> downloaded bundles were not being discovered, resulting in rather slow
>> clones. This was particularly problematic when employing the heuristic
>> `creationTokens`.
>>
>> And this is easy to reproduce. Suppose we have a repository with a
>> single branch `main` pointing to commit `A`, firstly we create a base
>> bundle with
>>
>> git bundle create base.bundle main
>>
>> Then let's add a new commit `B` on top of `A`, so that an incremental
>> bundle for `main` can be created with
>>
>> git bundle create incr.bundle A..main
>>
>> Now we can generate a bundle list with the following content:
>>
>> [bundle]
>> version = 1
>> mode = all
>> heuristic = creationToken
>>
>> [bundle "base"]
>> uri = base.bundle
>> creationToken = 1
>>
>> [bundle "incr"]
>> uri = incr.bundle
>> creationToken = 2
>>
>> A fresh clone with the bundle list above would give the expected
>> `refs/bundles/main` pointing at `B` in new repository, in other words we
>> already had everything locally from the bundles, but git would still
>> download everything from server as if we got nothing.
>>
>> So why the `refs/bundles/main` is not discovered? After some digging I
>> found that:
>>
>> 1. when unbundling a downloaded bundle, a `verify_bundle` is called to
>
>s/a//
Thanks!
>
>> check its prerequisites if any. The verify procedure would find oids
>> so `packed_git` is initialized.
>>
>
>So the flow is:
>1. `fetch_bundle_list` fetches all the bundles advertised via
>`download_bundle_list` to local files.
>2. It then calls `unbundle_all_bundles` to unbundle all the bundles.
>3. Each bundle is then unbundled using `unbundle_from_file`.
>4. Here, we first read the bundle header to get all the prerequisites
>for the bundle, this is done in `read_bundle_header`.
>5. Then we call `unbundle`, which calls `verify_bundle` to ensure that
>the repository does indeed contain the prerequisites mentioned in the
>bundle. Then it creates the index from the bundle file.
>
>So because the objects are being checked, the `prepare_packed_git`
>function is eventually called, which means that the
>`raw_object_store->packed_git` data gets filled in and
>`packed_git_initialized` is set.
>
>This means consecutive calls to `prepare_packed_git` doesn't
>re-initiate `raw_object_store->packed_git` since
>`packed_git_initialized` already is set.
>
>So your explanation makes sense, as a _nit_ I would perhaps add the part
>about why consecutive calls to `prepare_packed_git` are ineffective.
Thanks my friend, you have expressed this issue more clearly. I will
post a new description based on your explanation with the creationToken
case covered.
>
>> 2. after unbundled all bundles, we would enter `do_fetch_pack_v2`,
>
>s/unbundled/unbundling
Copy that.
>
>> +#include "packfile.h"
>> #include "pkt-line.h"
>> #include "config.h"
>> #include "remote.h"
>> @@ -376,6 +377,8 @@ static int unbundle_from_file(struct repository *r, const char *file)
>> VERIFY_BUNDLE_QUIET)))
>> return 1;
>>
>> + reprepare_packed_git(r);
>> +
>>
>
>Would it make sense to move this to `bundle.c:unbundle()`, since that is
>also where the idx is created?
>
I wonder if we need a mental model that we should `reprepare_packed_git`
that when a new pack and its corresponding idx is generated? Currently
whether to call `reprepare_packed_git` is determined by the caller.
But within the scope of this bug, I tend to remove the
`REF_SKIP_OID_VERIFICATION` flag when writing refs as Patrick suggested.
Xing Xin
next prev parent reply other threads:[~2024-05-20 10:20 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-15 3:01 [PATCH] bundle-uri: refresh packed_git if unbundle succeed blanet via GitGitGadget
2024-05-17 5:00 ` Patrick Steinhardt
2024-05-17 16:14 ` Junio C Hamano
2024-05-20 11:48 ` Xing Xin
2024-05-20 17:19 ` Junio C Hamano
2024-05-27 16:04 ` Xing Xin
2024-05-20 9:41 ` Xing Xin
2024-05-17 7:36 ` Karthik Nayak
2024-05-20 10:19 ` Xing Xin [this message]
2024-05-20 12:36 ` [PATCH v2] bundle-uri: verify oid before writing refs blanet via GitGitGadget
2024-05-21 15:41 ` Karthik Nayak
2024-05-27 15:41 ` [PATCH v3 0/4] object checking related additions and fixes for bundles in fetches blanet via GitGitGadget
2024-05-27 15:41 ` [PATCH v3 1/4] bundle-uri: verify oid before writing refs Xing Xin via GitGitGadget
2024-05-28 11:55 ` Patrick Steinhardt
2024-05-30 8:32 ` Xing Xin
2024-05-27 15:41 ` [PATCH v3 2/4] unbundle: introduce unbundle_fsck_flags for fsckobjects handling Xing Xin via GitGitGadget
2024-05-28 12:03 ` Patrick Steinhardt
2024-05-29 18:12 ` Xing Xin
2024-05-30 4:38 ` Patrick Steinhardt
2024-05-30 8:46 ` Xing Xin
2024-05-27 15:41 ` [PATCH v3 3/4] fetch-pack: expose fsckObjects configuration logic Xing Xin via GitGitGadget
2024-05-28 12:03 ` Patrick Steinhardt
2024-05-28 17:10 ` Junio C Hamano
2024-05-28 17:24 ` Junio C Hamano
2024-05-29 5:52 ` Patrick Steinhardt
2024-05-30 8:48 ` Xing Xin
2024-05-29 5:52 ` Patrick Steinhardt
2024-05-27 15:41 ` [PATCH v3 4/4] unbundle: introduce new option UNBUNDLE_FSCK_FOLLOW_FETCH Xing Xin via GitGitGadget
2024-05-28 12:05 ` Patrick Steinhardt
2024-05-30 8:54 ` Xing Xin
2024-05-30 8:21 ` [PATCH v4 0/4] object checking related additions and fixes for bundles in fetches blanet via GitGitGadget
2024-05-30 8:21 ` [PATCH v4 1/4] bundle-uri: verify oid before writing refs Xing Xin via GitGitGadget
2024-05-30 8:21 ` [PATCH v4 2/4] unbundle: extend verify_bundle_flags to support fsck-objects Xing Xin via GitGitGadget
2024-06-06 12:06 ` Patrick Steinhardt
2024-06-11 6:46 ` Xing Xin
2024-05-30 8:21 ` [PATCH v4 3/4] fetch-pack: expose fsckObjects configuration logic Xing Xin via GitGitGadget
2024-05-30 8:21 ` [PATCH v4 4/4] unbundle: introduce option VERIFY_BUNDLE_FSCK_FOLLOW_FETCH Xing Xin via GitGitGadget
2024-06-06 12:06 ` Patrick Steinhardt
2024-06-11 6:46 ` Xing Xin
2024-06-11 6:42 ` [PATCH v5 0/4] object checking related additions and fixes for bundles in fetches blanet via GitGitGadget
2024-06-11 6:42 ` [PATCH v5 1/4] bundle-uri: verify oid before writing refs Xing Xin via GitGitGadget
2024-06-11 6:42 ` [PATCH v5 2/4] fetch-pack: expose fsckObjects configuration logic Xing Xin via GitGitGadget
2024-06-11 6:42 ` [PATCH v5 3/4] unbundle: extend options to support object verification Xing Xin via GitGitGadget
2024-06-11 9:11 ` Patrick Steinhardt
2024-06-11 12:47 ` Xing Xin
2024-06-11 6:42 ` [PATCH v5 4/4] unbundle: use VERIFY_BUNDLE_FSCK_FOLLOW_FETCH for fetches Xing Xin via GitGitGadget
2024-06-11 12:45 ` [PATCH v6 0/3] object checking related additions and fixes for bundles in fetches blanet via GitGitGadget
2024-06-11 12:45 ` [PATCH v6 1/3] bundle-uri: verify oid before writing refs Xing Xin via GitGitGadget
2024-06-11 19:08 ` Junio C Hamano
2024-06-17 13:53 ` Xing Xin
2024-06-11 12:45 ` [PATCH v6 2/3] fetch-pack: expose fsckObjects configuration logic Xing Xin via GitGitGadget
2024-06-11 19:20 ` Junio C Hamano
2024-06-11 12:45 ` [PATCH v6 3/3] unbundle: support object verification for fetches Xing Xin via GitGitGadget
2024-06-11 20:05 ` Junio C Hamano
2024-06-12 18:33 ` Xing Xin
2024-06-11 13:14 ` [PATCH v6 0/3] object checking related additions and fixes for bundles in fetches Patrick Steinhardt
2024-06-17 13:55 ` [PATCH v7 " blanet via GitGitGadget
2024-06-17 13:55 ` [PATCH v7 1/3] bundle-uri: verify oid before writing refs Xing Xin via GitGitGadget
2024-06-18 17:37 ` Junio C Hamano
2024-06-19 6:30 ` Xing Xin
2024-06-17 13:55 ` [PATCH v7 2/3] fetch-pack: expose fsckObjects configuration logic Xing Xin via GitGitGadget
2024-06-17 13:55 ` [PATCH v7 3/3] unbundle: extend object verification for fetches Xing Xin via GitGitGadget
2024-06-19 4:07 ` [PATCH v8 0/3] object checking related additions and fixes for bundles in fetches blanet via GitGitGadget
2024-06-19 4:07 ` [PATCH v8 1/3] bundle-uri: verify oid before writing refs Xing Xin via GitGitGadget
2024-06-19 4:07 ` [PATCH v8 2/3] fetch-pack: expose fsckObjects configuration logic Xing Xin via GitGitGadget
2024-06-19 4:07 ` [PATCH v8 3/3] unbundle: extend object verification for fetches Xing Xin via GitGitGadget
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
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=59d5f488.ad90.18f9583cbc2.Coremail.bupt_xingxin@163.com \
--to=bupt_xingxin@163.com \
--cc=git@vger.kernel.org \
--cc=gitgitgadget@gmail.com \
--cc=karthik.188@gmail.com \
--cc=xingxin.xx@bytedance.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.
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).