On 06/06/2019 15:15, Derrick Stolee via GitGitGadget wrote:
> From: Derrick Stolee <dsto...@microsoft.com>
>
> The split commit-graph feature is now fully implemented, but needs
> some more run-time configurability. Allow direct callers to 'git
> commit-graph write --split' to specify the values used in the
> merge strategy and the expire time.
>
> Update the documentation to specify these values.
>
> Signed-off-by: Derrick Stolee <dsto...@microsoft.com>
> ---
> Documentation/git-commit-graph.txt | 21 +++++++++++++-
> Documentation/technical/commit-graph.txt | 7 +++--
> builtin/commit-graph.c | 20 +++++++++++---
> builtin/commit.c | 2 +-
> builtin/gc.c | 3 +-
> commit-graph.c | 35 ++++++++++++++++--------
> commit-graph.h | 12 ++++++--
> t/t5323-split-commit-graph.sh | 35 ++++++++++++++++++++++++
> 8 files changed, 112 insertions(+), 23 deletions(-)
>
> diff --git a/Documentation/git-commit-graph.txt
> b/Documentation/git-commit-graph.txt
> index 624470e198..365e145e82 100644
> --- a/Documentation/git-commit-graph.txt
> +++ b/Documentation/git-commit-graph.txt
> @@ -26,7 +26,7 @@ OPTIONS
> Use given directory for the location of packfiles and commit-graph
> file. This parameter exists to specify the location of an alternate
> that only has the objects directory, not a full `.git` directory. The
> - commit-graph file is expected to be at `<dir>/info/commit-graph` and
> + commit-graph file is expected to be in the `<dir>/info` directory and
> the packfiles are expected to be in `<dir>/pack`.
>
>
> @@ -51,6 +51,25 @@ or `--stdin-packs`.)
> +
> With the `--append` option, include all commits that are present in the
> existing commit-graph file.
> ++
> +With the `--split` option, write the commit-graph as a chain of multiple
> +commit-graph files stored in `<dir>/info/commit-graphs`. The new commits
> +not already in the commit-graph are added in a new "tip" file. This file
> +is merged with the existing file if the following merge conditions are
> +met:
> ++
> +* If `--size-multiple=<X>` is not specified, let `X` equal 2. If the new
> +tip file would have `N` commits and the previous tip has `M` commits and
> +`X` times `N` is greater than `M`, instead merge the two files into a
> +single file.
> ++
> +* If `--max-commits=<M>` is specified with `M` a positive integer, and the
> +new tip file would have more than `M` commits, then instead merge the new
> +tip with the previous tip.
> ++
> +Finally, if `--expire-time=<datetime>` is not specified, let `datetime`
> +be the current time. After writing the split commit-graph, delete all
> +unused commit-graph whose modified times are older than `datetime`.
>
> 'read'::
>
> diff --git a/Documentation/technical/commit-graph.txt
> b/Documentation/technical/commit-graph.txt
> index aed4350a59..729fbcb32f 100644
> --- a/Documentation/technical/commit-graph.txt
> +++ b/Documentation/technical/commit-graph.txt
> @@ -248,10 +248,11 @@ When writing a set of commits that do not exist in the
> commit-graph stack of
> height N, we default to creating a new file at level N + 1. We then decide to
> merge with the Nth level if one of two conditions hold:
>
> - 1. The expected file size for level N + 1 is at least half the file size
> for
> - level N.
> + 1. `--size-multiple=<X>` is specified or X = 2, and the number of commits
> in
> + level N is less than X times the number of commits in level N + 1.
>
> - 2. Level N + 1 contains more than 64,0000 commits.
> + 2. `--max-commits=<C>` is specified with non-zero C and the number of
> commits
> + in level N + 1 is more than C commits.
>
> This decision cascades down the levels: when we merge a level we create a new
> set of commits that then compares to the next level.
> diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
> index c2c07d3917..18e3b61fb6 100644
> --- a/builtin/commit-graph.c
> +++ b/builtin/commit-graph.c
> @@ -10,7 +10,7 @@ static char const * const builtin_commit_graph_usage[] = {
> N_("git commit-graph [--object-dir <objdir>]"),
> N_("git commit-graph read [--object-dir <objdir>]"),
> N_("git commit-graph verify [--object-dir <objdir>]"),
> - N_("git commit-graph write [--object-dir <objdir>] [--append|--split]
> [--reachable|--stdin-packs|--stdin-commits]"),
> + N_("git commit-graph write [--object-dir <objdir>] [--append|--split]
> [--reachable|--stdin-packs|--stdin-commits] <split options>"),
> NULL
> };
>
> @@ -25,7 +25,7 @@ static const char * const builtin_commit_graph_read_usage[]
> = {
> };
>
> static const char * const builtin_commit_graph_write_usage[] = {
> - N_("git commit-graph write [--object-dir <objdir>] [--append|--split]
> [--reachable|--stdin-packs|--stdin-commits]"),
> + N_("git commit-graph write [--object-dir <objdir>] [--append|--split]
> [--reachable|--stdin-packs|--stdin-commits] <split options>"),
> NULL
> };
>
> @@ -135,6 +135,7 @@ static int graph_read(int argc, const char **argv)
> }
>
> extern int read_replace_refs;
> +struct split_commit_graph_opts split_opts;
This 'split_opts' variable needs to be marked 'static'.
Thanks.
ATB,
Ramsay Jones
