From: Karthik Nayak <karthik.188@gmail.com>
To: blanet via GitGitGadget <gitgitgadget@gmail.com>, git@vger.kernel.org
Cc: blanet <bupt_xingxin@163.com>, Xing Xin <xingxin.xx@bytedance.com>
Subject: Re: [PATCH] bundle-uri: refresh packed_git if unbundle succeed
Date: Fri, 17 May 2024 07:36:53 +0000 [thread overview]
Message-ID: <CAOLa=ZT=x6bmnvJO2KtbJvVOvt=4LH1RgU1NMJYpTgW2XXfGVg@mail.gmail.com> (raw)
In-Reply-To: <pull.1730.git.1715742069966.gitgitgadget@gmail.com>
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"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//
> 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.
> 2. after unbundled all bundles, we would enter `do_fetch_pack_v2`,
s/unbundled/unbundling
> during which `mark_complete_and_common_ref` and `mark_tips` would
> find oids with `OBJECT_INFO_QUICK` flag set, so no new packs would be
> enlisted if `packed_git` has already initialized in 1.
> Back to the example above, when unbunding `incr.bundle`, `base.pack` is
> enlisted to `packed_git` bacause of the prerequisites to verify. Then we
> can not find `B` for negotiation at a latter time bacause `B` exists in
> `incr.pack` which is not enlisted in `packed_git`.
>
> This commit fixes this by adding a `reprepare_packed_git` call for every
> successfully unbundled bundle, which ensures to enlist all generated
> packs from bundle uri. And a set of negotiation related tests are added.
>
The solution makes sense.
> Signed-off-by: Xing Xin <xingxin.xx@bytedance.com>
> ---
> bundle-uri: refresh packed_git if unbundle succeed
>
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1730%2Fblanet%2Fxx%2Fbundle-uri-bug-using-bundle-list-v1
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1730/blanet/xx/bundle-uri-bug-using-bundle-list-v1
> Pull-Request: https://github.com/gitgitgadget/git/pull/1730
>
> bundle-uri.c | 3 +
> t/t5558-clone-bundle-uri.sh | 129 ++++++++++++++++++++++++++++++++++++
> 2 files changed, 132 insertions(+)
>
> diff --git a/bundle-uri.c b/bundle-uri.c
> index ca32050a78f..2b9d36cfd8e 100644
> --- a/bundle-uri.c
> +++ b/bundle-uri.c
> @@ -7,6 +7,7 @@
> #include "refs.h"
> #include "run-command.h"
> #include "hashmap.h"
> +#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?
[snip]
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next prev parent reply other threads:[~2024-05-17 7:36 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 [this message]
2024-05-20 10:19 ` Xing Xin
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
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