It can be tedious to wait for a multi-million-revision import.
Unfortunately it is hard to spy on the import because fast-import
works by continuously streaming out objects, without updating the pack
index or refs until a checkpoint command or the end of the stream.
So allow the impatient operator to request checkpoints by sending a
signal, like so:
killall -USR1 git-fast-import
When receiving such a signal, fast-import would schedule a checkpoint
to take place after the current top-level command (usually a "commit"
or "blob" request) finishes.
Caveats: just like ordinary checkpoint commands, such requests slow
down the import. Switching to a new pack at a suboptimal moment is
also likely to result in a less dense initial collection of packs.
That's the price.
Signed-off-by: Jonathan Nieder <jrnieder@xxxxxxxxx>
---
Thoughts?
Documentation/git-fast-import.txt | 8 +++++++
fast-import.c | 42 ++++++++++++++++++++++++++++++++++++-
2 files changed, 49 insertions(+), 1 deletions(-)
diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt
index 5d0c245..526670a 100644
--- a/Documentation/git-fast-import.txt
+++ b/Documentation/git-fast-import.txt
@@ -1233,6 +1233,14 @@ and lazy loading of subtrees, allows fast-import to efficiently import
projects with 2,000+ branches and 45,114+ files in a very limited
memory footprint (less than 2.7 MiB per active branch).
+Signals
+-------
+Sending *SIGUSR1* to the 'git fast-import' process ends the current
+packfile early, simulating a `checkpoint` command. The impatient
+operator can use this facility to peek at the objects and refs from an
+import in progress, at the cost of some added running time and worse
+compression.
+
Author
------
diff --git a/fast-import.c b/fast-import.c
index 77549eb..4779e3a 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -361,6 +361,9 @@ static uintmax_t next_mark;
static struct strbuf new_data = STRBUF_INIT;
static int seen_data_command;
+/* Signal handling */
+static volatile sig_atomic_t checkpoint_requested;
+
static void parse_argv(void);
static void write_branch_report(FILE *rpt, struct branch *b)
@@ -500,6 +503,33 @@ static NORETURN void die_nicely(const char *err, va_list params)
exit(128);
}
+#ifndef SIGUSR1 /* Windows, for example */
+
+static void set_checkpoint_signal(void)
+{
+ /* nothing */
+}
+
+#else
+
+static void checkpoint_signal(int signo)
+{
+ checkpoint_requested = 1;
+}
+
+static void set_checkpoint_signal(void)
+{
+ struct sigaction sa;
+
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_handler = checkpoint_signal;
+ sigemptyset(&sa.sa_mask);
+ sa.sa_flags = SA_RESTART;
+ sigaction(SIGUSR1, &sa, NULL);
+}
+
+#endif
+
static void alloc_objects(unsigned int cnt)
{
struct object_entry_pool *b;
@@ -2689,14 +2719,20 @@ static void parse_reset_branch(void)
unread_command_buf = 1;
}
-static void parse_checkpoint(void)
+static void do_checkpoint(void)
{
+ checkpoint_requested = 0;
if (object_count) {
cycle_packfile();
dump_branches();
dump_tags();
dump_marks();
}
+}
+
+static void parse_checkpoint(void)
+{
+ do_checkpoint();
skip_optional_lf();
}
@@ -2953,6 +2989,7 @@ int main(int argc, const char **argv)
prepare_packed_git();
start_packfile();
set_die_routine(die_nicely);
+ set_checkpoint_signal();
while (read_next_command() != EOF) {
if (!strcmp("blob", command_buf.buf))
parse_new_blob();
@@ -2974,6 +3011,9 @@ int main(int argc, const char **argv)
/* ignore non-git options*/;
else
die("Unsupported command: %s", command_buf.buf);
+
+ if (checkpoint_requested)
+ do_checkpoint();
}
/* argv hasn't been parsed yet, do so */
--
1.7.2.3
--
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