From: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
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 <dstolee@xxxxxxxxxxxxx>
---
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/t5324-split-commit-graph.sh | 47 ++++++++++++++++++++++++
8 files changed, 124 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..cc4af67820 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;
+static struct split_commit_graph_opts split_opts;
static int graph_write(int argc, const char **argv)
{
@@ -158,9 +159,19 @@ static int graph_write(int argc, const char **argv)
N_("include all commits already in the commit-graph file")),
OPT_BOOL(0, "split", &opts.split,
N_("allow writing an incremental commit-graph file")),
+ OPT_INTEGER(0, "max-commits", &split_opts.max_commits,
+ N_("maximum number of commits in a non-base split commit-graph")),
+ OPT_INTEGER(0, "size-multiple", &split_opts.size_multiple,
+ N_("maximum ratio between two levels of a split commit-graph")),
+ OPT_EXPIRY_DATE(0, "expire-time", &split_opts.expire_time,
+ N_("maximum number of commits in a non-base split commit-graph")),
OPT_END(),
};
+ split_opts.size_multiple = 2;
+ split_opts.max_commits = 0;
+ split_opts.expire_time = 0;
+
argc = parse_options(argc, argv, NULL,
builtin_commit_graph_write_options,
builtin_commit_graph_write_usage, 0);
@@ -177,7 +188,7 @@ static int graph_write(int argc, const char **argv)
read_replace_refs = 0;
if (opts.reachable)
- return write_commit_graph_reachable(opts.obj_dir, flags);
+ return write_commit_graph_reachable(opts.obj_dir, flags, &split_opts);
string_list_init(&lines, 0);
if (opts.stdin_packs || opts.stdin_commits) {
@@ -197,7 +208,8 @@ static int graph_write(int argc, const char **argv)
result = write_commit_graph(opts.obj_dir,
pack_indexes,
commit_hex,
- flags);
+ flags,
+ &split_opts);
UNLEAK(lines);
return result;
diff --git a/builtin/commit.c b/builtin/commit.c
index b001ef565d..9216e9c043 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1670,7 +1670,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
"not exceeded, and then \"git reset HEAD\" to recover."));
if (git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
- write_commit_graph_reachable(get_object_directory(), 0))
+ write_commit_graph_reachable(get_object_directory(), 0, NULL))
return 1;
repo_rerere(the_repository, 0);
diff --git a/builtin/gc.c b/builtin/gc.c
index df2573f124..2ab590ffd4 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -666,7 +666,8 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
if (gc_write_commit_graph &&
write_commit_graph_reachable(get_object_directory(),
- !quiet && !daemonized ? COMMIT_GRAPH_PROGRESS : 0))
+ !quiet && !daemonized ? COMMIT_GRAPH_PROGRESS : 0,
+ NULL))
return 1;
if (auto_gc && too_many_loose_objects())
diff --git a/commit-graph.c b/commit-graph.c
index 779a628c95..888eaa7d03 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -766,6 +766,8 @@ struct write_commit_graph_context {
unsigned append:1,
report_progress:1,
split:1;
+
+ const struct split_commit_graph_opts *split_opts;
};
static void write_graph_chunk_fanout(struct hashfile *f,
@@ -1114,14 +1116,15 @@ static int add_ref_to_list(const char *refname,
return 0;
}
-int write_commit_graph_reachable(const char *obj_dir, unsigned int flags)
+int write_commit_graph_reachable(const char *obj_dir, unsigned int flags,
+ const struct split_commit_graph_opts *split_opts)
{
struct string_list list = STRING_LIST_INIT_DUP;
int result;
for_each_ref(add_ref_to_list, &list);
result = write_commit_graph(obj_dir, NULL, &list,
- flags);
+ flags, split_opts);
string_list_clear(&list, 0);
return result;
@@ -1496,20 +1499,25 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
return 0;
}
-static int split_strategy_max_commits = 64000;
-static float split_strategy_size_mult = 2.0f;
-
static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
{
struct commit_graph *g = ctx->r->objects->commit_graph;
uint32_t num_commits = ctx->commits.nr;
uint32_t i;
+ int max_commits = 0;
+ int size_mult = 2;
+
+ if (ctx->split_opts) {
+ max_commits = ctx->split_opts->max_commits;
+ size_mult = ctx->split_opts->size_multiple;
+ }
+
g = ctx->r->objects->commit_graph;
ctx->num_commit_graphs_after = ctx->num_commit_graphs_before + 1;
- while (g && (g->num_commits <= split_strategy_size_mult * num_commits ||
- num_commits > split_strategy_max_commits)) {
+ while (g && (g->num_commits <= size_mult * num_commits ||
+ (max_commits && num_commits > max_commits))) {
if (strcmp(g->obj_dir, ctx->obj_dir))
break;
@@ -1673,7 +1681,10 @@ static void expire_commit_graphs(struct write_commit_graph_context *ctx)
DIR *dir;
struct dirent *de;
size_t dirnamelen;
- time_t expire_time = time(NULL);
+ timestamp_t expire_time = time(NULL);
+
+ if (ctx->split_opts && ctx->split_opts->expire_time)
+ expire_time -= ctx->split_opts->expire_time;
strbuf_addstr(&path, ctx->obj_dir);
strbuf_addstr(&path, "/info/commit-graphs");
@@ -1717,7 +1728,8 @@ static void expire_commit_graphs(struct write_commit_graph_context *ctx)
int write_commit_graph(const char *obj_dir,
struct string_list *pack_indexes,
struct string_list *commit_hex,
- unsigned int flags)
+ unsigned int flags,
+ const struct split_commit_graph_opts *split_opts)
{
struct write_commit_graph_context *ctx;
uint32_t i, count_distinct = 0;
@@ -1732,6 +1744,7 @@ int write_commit_graph(const char *obj_dir,
ctx->append = flags & COMMIT_GRAPH_APPEND ? 1 : 0;
ctx->report_progress = flags & COMMIT_GRAPH_PROGRESS ? 1 : 0;
ctx->split = flags & COMMIT_GRAPH_SPLIT ? 1 : 0;
+ ctx->split_opts = split_opts;
if (ctx->split) {
struct commit_graph *g;
@@ -1759,8 +1772,8 @@ int write_commit_graph(const char *obj_dir,
ctx->approx_nr_objects = approximate_object_count();
ctx->oids.alloc = ctx->approx_nr_objects / 32;
- if (ctx->split && ctx->oids.alloc > split_strategy_max_commits)
- ctx->oids.alloc = split_strategy_max_commits;
+ if (ctx->split && split_opts && ctx->oids.alloc > split_opts->max_commits)
+ ctx->oids.alloc = split_opts->max_commits;
if (ctx->append) {
prepare_commit_graph_one(ctx->r, ctx->obj_dir);
diff --git a/commit-graph.h b/commit-graph.h
index 10466bc064..194acab2b7 100644
--- a/commit-graph.h
+++ b/commit-graph.h
@@ -75,11 +75,19 @@ int generation_numbers_enabled(struct repository *r);
#define COMMIT_GRAPH_PROGRESS (1 << 1)
#define COMMIT_GRAPH_SPLIT (1 << 2)
-int write_commit_graph_reachable(const char *obj_dir, unsigned int flags);
+struct split_commit_graph_opts {
+ int size_multiple;
+ int max_commits;
+ timestamp_t expire_time;
+};
+
+int write_commit_graph_reachable(const char *obj_dir, unsigned int flags,
+ const struct split_commit_graph_opts *split_opts);
int write_commit_graph(const char *obj_dir,
struct string_list *pack_indexes,
struct string_list *commit_hex,
- unsigned int flags);
+ unsigned int flags,
+ const struct split_commit_graph_opts *split_opts);
int verify_commit_graph(struct repository *r, struct commit_graph *g);
diff --git a/t/t5324-split-commit-graph.sh b/t/t5324-split-commit-graph.sh
index 76068ee407..1b699a543c 100755
--- a/t/t5324-split-commit-graph.sh
+++ b/t/t5324-split-commit-graph.sh
@@ -169,4 +169,51 @@ test_expect_success 'create fork and chain across alternate' '
graph_git_behavior 'alternate: commit 13 vs 6' commits/13 commits/6
+test_expect_success 'test merge stragety constants' '
+ git clone . merge-2 &&
+ (
+ cd merge-2 &&
+ git config core.commitGraph true &&
+ test_line_count = 2 $graphdir/commit-graph-chain &&
+ test_commit 14 &&
+ git commit-graph write --reachable --split --size-multiple=2 &&
+ test_line_count = 3 $graphdir/commit-graph-chain
+
+ ) &&
+ git clone . merge-10 &&
+ (
+ cd merge-10 &&
+ git config core.commitGraph true &&
+ test_line_count = 2 $graphdir/commit-graph-chain &&
+ test_commit 14 &&
+ git commit-graph write --reachable --split --size-multiple=10 &&
+ test_line_count = 1 $graphdir/commit-graph-chain &&
+ ls $graphdir/graph-*.graph >graph-files &&
+ test_line_count = 1 graph-files
+ ) &&
+ git clone . merge-10-expire &&
+ (
+ cd merge-10-expire &&
+ git config core.commitGraph true &&
+ test_line_count = 2 $graphdir/commit-graph-chain &&
+ test_commit 15 &&
+ git commit-graph write --reachable --split --size-multiple=10 --expire-time=1980-01-01 &&
+ test_line_count = 1 $graphdir/commit-graph-chain &&
+ ls $graphdir/graph-*.graph >graph-files &&
+ test_line_count = 3 graph-files
+ ) &&
+ git clone --no-hardlinks . max-commits &&
+ (
+ cd max-commits &&
+ git config core.commitGraph true &&
+ test_line_count = 2 $graphdir/commit-graph-chain &&
+ test_commit 16 &&
+ test_commit 17 &&
+ git commit-graph write --reachable --split --max-commits=1 &&
+ test_line_count = 1 $graphdir/commit-graph-chain &&
+ ls $graphdir/graph-*.graph >graph-files &&
+ test_line_count = 1 graph-files
+ )
+'
+
test_done
--
gitgitgadget
