On 25/02/07 12:57PM, Karthik Nayak wrote:
> The 'git-refs(1)' migrate subcommand, which transfers repositories
> between reference backends, currently migrates reflogs by default as of
> In 246cebe320 (refs: add support for migrating reflogs, 2024-12-16).
s/In 246cebe320/246cebe320/
> While this behavior is desirable for most client-side repositories,
> server-side repositories typically don't use reflogs and the migration
> of these entries is unnecessary overhead.
>
> Add a '--skip-reflog' flag to the migrate subcommand to make reflog
> migration optional. This is particularly useful for server-side
> migrations where reflogs are not needed, improving migration performance
> in these scenarios.
Just to clarify, does a repository already without reflogs see improved
migration performance with this `--skip-reflog` flag? Or is the improved
performance soley due to repositories with reflogs skipping that part of
the migration?
>
> Signed-off-by: Karthik Nayak <karthik.188@xxxxxxxxx>
> ---
> ---
> builtin/refs.c | 3 +++
> refs.c | 8 +++++---
> refs.h | 5 ++++-
> t/t1460-refs-migrate.sh | 17 +++++++++++++++--
> 4 files changed, 27 insertions(+), 6 deletions(-)
>
> diff --git a/builtin/refs.c b/builtin/refs.c
> index a29f19583474518ee0942ea53c39cbdf9661c5e2..30be0254c14dd3d07693d70c25dddc9990756e9c 100644
> --- a/builtin/refs.c
> +++ b/builtin/refs.c
> @@ -30,6 +30,9 @@ static int cmd_refs_migrate(int argc, const char **argv, const char *prefix,
> OPT_BIT(0, "dry-run", &flags,
> N_("perform a non-destructive dry-run"),
> REPO_MIGRATE_REF_STORAGE_FORMAT_DRYRUN),
> + OPT_BIT(0, "skip-reflog", &flags,
> + N_("skip migrating reflogs"),
> + REPO_MIGRATE_REF_STORAGE_FORMAT_SKIP_REFLOG),
> OPT_END(),
> };
> struct strbuf errbuf = STRBUF_INIT;
> diff --git a/refs.c b/refs.c
> index f4094a326a9f88f979654b668cc9c3d27d83cb5d..5e8f5c06fa68d16c93ee11edd9742995eea994b6 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -3035,9 +3035,11 @@ int repo_migrate_ref_storage_format(struct repository *repo,
> if (ret < 0)
> goto done;
>
> - ret = refs_for_each_reflog(old_refs, migrate_one_reflog, &data);
> - if (ret < 0)
> - goto done;
> + if (!(flags & REPO_MIGRATE_REF_STORAGE_FORMAT_SKIP_REFLOG)) {
> + ret = refs_for_each_reflog(old_refs, migrate_one_reflog, &data);
> + if (ret < 0)
> + goto done;
> + }
When the `REPO_MIGRATE_REF_STORAGE_FORMAT_SKIP_REFLOG` flag is set, we
now skip over all the logs to perform the reflog migration. Makes sense.
-Justin
>
> ret = ref_transaction_commit(transaction, errbuf);
> if (ret < 0)
> diff --git a/refs.h b/refs.h
> index a0cdd99250e8286b55808b697b0a94afac5d8319..ccee8fc6705e6e93a1c6234e7395180f8dfd815b 100644
> --- a/refs.h
> +++ b/refs.h
> @@ -1157,8 +1157,11 @@ int is_pseudo_ref(const char *refname);
> * - REPO_MIGRATE_REF_STORAGE_FORMAT_DRYRUN: perform a dry-run migration
> * without touching the main repository. The result will be written into a
> * temporary ref storage directory.
> + *
> + * - REPO_MIGRATE_REF_STORAGE_FORMAT_SKIP_REFLOG: skip migration of reflogs.
> */
> -#define REPO_MIGRATE_REF_STORAGE_FORMAT_DRYRUN (1 << 0)
> +#define REPO_MIGRATE_REF_STORAGE_FORMAT_DRYRUN (1 << 0)
> +#define REPO_MIGRATE_REF_STORAGE_FORMAT_SKIP_REFLOG (1 << 1)
>
> /*
> * Migrate the ref storage format used by the repository to the
> diff --git a/t/t1460-refs-migrate.sh b/t/t1460-refs-migrate.sh
> index a6d9b35a46eb59350aa0d59d982a2fbfaecf1448..9059d4c4121842a9d2e77dc4e54c537eeff8afab 100755
> --- a/t/t1460-refs-migrate.sh
> +++ b/t/t1460-refs-migrate.sh
> @@ -9,14 +9,16 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
>
> # Migrate the provided repository from one format to the other and
> # verify that the references and logs are migrated over correctly.
> -# Usage: test_migration <repo> <format> <skip_reflog_verify>
> +# Usage: test_migration <repo> <format> <skip_reflog_verify> <...options>
> # <repo> is the relative path to the repo to be migrated.
> # <format> is the ref format to be migrated to.
> # <skip_reflog_verify> (true or false) whether to skip reflog verification.
> +# <...options> are other options be passed directly to 'git refs migrate'.
> test_migration () {
> repo=$1 &&
> format=$2 &&
> skip_reflog_verify=${3:-false} &&
> + shift $(( $# >= 3 ? 3 : 2 )) &&
> git -C "$repo" for-each-ref --include-root-refs \
> --format='%(refname) %(objectname) %(symref)' >expect &&
> if ! $skip_reflog_verify
> @@ -25,7 +27,7 @@ test_migration () {
> git -C "$repo" reflog list >expect_log_list
> fi &&
>
> - git -C "$repo" refs migrate --ref-format="$2" &&
> + git -C "$repo" refs migrate --ref-format="$format" $@ &&
>
> git -C "$repo" for-each-ref --include-root-refs \
> --format='%(refname) %(objectname) %(symref)' >actual &&
> @@ -241,6 +243,17 @@ do
> test_cmp expect.reflog actual.reflog
> )
> '
> +
> + test_expect_success "$from_format -> $to_format: skip reflog with --skip-reflog" '
> + test_when_finished "rm -rf repo" &&
> + git init --ref-format=$from_format repo &&
> + test_commit -C repo initial &&
> + # we see that the repository contains reflogs.
> + test 2 = $(git -C repo reflog --all | wc -l) &&
> + test_migration repo "$to_format" true --skip-reflog &&
> + # there should be no reflogs post migration.
> + test 0 = $(git -C repo reflog --all | wc -l)
> + '
> done
> done
>
>
> ---
>
> base-commit: bc204b742735ae06f65bb20291c95985c9633b7f
> change-id: 20250207-477-refs-migrate-add-a-flag-to-ignore-reflogs-during-migration-8066f6df50ac
>
> Thanks
> - Karthik
>
>
