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From: Jonathan Tan <jonathantanmy@google.com>
To: git@vger.kernel.org
Cc: Jonathan Tan <jonathantanmy@google.com>,
	gitster@pobox.com, git@jeffhostetler.com, peartben@gmail.com,
	christian.couder@gmail.com
Subject: [PATCH 17/18] unpack-trees: batch fetching of missing blobs
Date: Fri, 29 Sep 2017 13:11:53 -0700
Message-ID: <73f9648b4c258eae1d02f91f12250ea139b72519.1506714999.git.jonathantanmy@google.com> (raw)
In-Reply-To: <cover.1506714999.git.jonathantanmy@google.com>

When running checkout, first prefetch all blobs that are to be updated
but are missing. This means that only one pack is downloaded during such
operations, instead of one per missing blob.

This operates only on the blob level - if a repository has a missing
tree, they are still fetched one at a time.

This does not use the delayed checkout mechanism introduced in commit
2841e8f ("convert: add "status=delayed" to filter process protocol",
2017-06-30) due to significant conceptual differences - in particular,
for partial clones, we already know what needs to be fetched based on
the contents of the local repo alone, whereas for status=delayed, it is
the filter process that tells us what needs to be checked in the end.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
---
 fetch-object.c   | 27 +++++++++++++++++++++++----
 fetch-object.h   |  5 +++++
 t/t5601-clone.sh | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 unpack-trees.c   | 22 ++++++++++++++++++++++
 4 files changed, 102 insertions(+), 4 deletions(-)

diff --git a/fetch-object.c b/fetch-object.c
index 369b61c0e..21b4dfafc 100644
--- a/fetch-object.c
+++ b/fetch-object.c
@@ -3,12 +3,12 @@
 #include "pkt-line.h"
 #include "strbuf.h"
 #include "transport.h"
+#include "fetch-object.h"
 
-void fetch_object(const char *remote_name, const unsigned char *sha1)
+static void fetch_refs(const char *remote_name, struct ref *ref)
 {
 	struct remote *remote;
 	struct transport *transport;
-	struct ref *ref;
 	int original_fetch_if_missing = fetch_if_missing;
 
 	fetch_if_missing = 0;
@@ -17,10 +17,29 @@ void fetch_object(const char *remote_name, const unsigned char *sha1)
 		die(_("Remote with no URL"));
 	transport = transport_get(remote, remote->url[0]);
 
-	ref = alloc_ref(sha1_to_hex(sha1));
-	hashcpy(ref->old_oid.hash, sha1);
 	transport_set_option(transport, TRANS_OPT_FROM_PROMISOR, "1");
 	transport_set_option(transport, TRANS_OPT_NO_HAVES, "1");
 	transport_fetch_refs(transport, ref);
 	fetch_if_missing = original_fetch_if_missing;
 }
+
+void fetch_object(const char *remote_name, const unsigned char *sha1)
+{
+	struct ref *ref = alloc_ref(sha1_to_hex(sha1));
+	hashcpy(ref->old_oid.hash, sha1);
+	fetch_refs(remote_name, ref);
+}
+
+void fetch_objects(const char *remote_name, const struct oid_array *to_fetch)
+{
+	struct ref *ref = NULL;
+	int i;
+
+	for (i = 0; i < to_fetch->nr; i++) {
+		struct ref *new_ref = alloc_ref(oid_to_hex(&to_fetch->oid[i]));
+		oidcpy(&new_ref->old_oid, &to_fetch->oid[i]);
+		new_ref->next = ref;
+		ref = new_ref;
+	}
+	fetch_refs(remote_name, ref);
+}
diff --git a/fetch-object.h b/fetch-object.h
index f371300c8..4b269d07e 100644
--- a/fetch-object.h
+++ b/fetch-object.h
@@ -1,6 +1,11 @@
 #ifndef FETCH_OBJECT_H
 #define FETCH_OBJECT_H
 
+#include "sha1-array.h"
+
 extern void fetch_object(const char *remote_name, const unsigned char *sha1);
 
+extern void fetch_objects(const char *remote_name,
+			  const struct oid_array *to_fetch);
+
 #endif
diff --git a/t/t5601-clone.sh b/t/t5601-clone.sh
index 951b1ffa8..0ca24c215 100755
--- a/t/t5601-clone.sh
+++ b/t/t5601-clone.sh
@@ -611,6 +611,58 @@ test_expect_success 'partial clone: warn if server does not support blob-max-byt
 	test_i18ngrep "blob-max-bytes not recognized by server" err
 '
 
+test_expect_success 'batch missing blob request during checkout' '
+	rm -rf server client &&
+
+	test_create_repo server &&
+	echo a >server/a &&
+	echo b >server/b &&
+	git -C server add a b &&
+
+	git -C server commit -m x &&
+	echo aa >server/a &&
+	echo bb >server/b &&
+	git -C server add a b &&
+	git -C server commit -m x &&
+
+	test_config -C server uploadpack.advertiseblobmaxbytes 1 &&
+	test_config -C server uploadpack.allowanysha1inwant 1 &&
+
+	git clone --blob-max-bytes=0 "file://$(pwd)/server" client &&
+
+	# Ensure that there is only one negotiation by checking that there is
+	# only "done" line sent. ("done" marks the end of negotiation.)
+	GIT_TRACE_PACKET="$(pwd)/trace" git -C client checkout HEAD^ &&
+	grep "git> done" trace >done_lines &&
+	test_line_count = 1 done_lines
+'
+
+test_expect_success 'batch missing blob request does not inadvertently try to fetch gitlinks' '
+	rm -rf server client &&
+
+	test_create_repo repo_for_submodule &&
+	test_commit -C repo_for_submodule x &&
+
+	test_create_repo server &&
+	echo a >server/a &&
+	echo b >server/b &&
+	git -C server add a b &&
+	git -C server commit -m x &&
+
+	echo aa >server/a &&
+	echo bb >server/b &&
+	# Also add a gitlink pointing to an arbitrary repository
+	git -C server submodule add "$(pwd)/repo_for_submodule" c &&
+	git -C server add a b c &&
+	git -C server commit -m x &&
+
+	test_config -C server uploadpack.advertiseblobmaxbytes 1 &&
+	test_config -C server uploadpack.allowanysha1inwant 1 &&
+
+	# Make sure that it succeeds
+	git clone --blob-max-bytes=0 "file://$(pwd)/server" client
+'
+
 . "$TEST_DIRECTORY"/lib-httpd.sh
 start_httpd
 
diff --git a/unpack-trees.c b/unpack-trees.c
index 71b70ccb1..73a1cdb43 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -14,6 +14,7 @@
 #include "dir.h"
 #include "submodule.h"
 #include "submodule-config.h"
+#include "fetch-object.h"
 
 /*
  * Error messages expected by scripts out of plumbing commands such as
@@ -369,6 +370,27 @@ static int check_updates(struct unpack_trees_options *o)
 		load_gitmodules_file(index, &state);
 
 	enable_delayed_checkout(&state);
+	if (repository_format_partial_clone && o->update && !o->dry_run) {
+		/*
+		 * Prefetch the objects that are to be checked out in the loop
+		 * below.
+		 */
+		struct oid_array to_fetch = OID_ARRAY_INIT;
+		int fetch_if_missing_store = fetch_if_missing;
+		fetch_if_missing = 0;
+		for (i = 0; i < index->cache_nr; i++) {
+			struct cache_entry *ce = index->cache[i];
+			if ((ce->ce_flags & CE_UPDATE) &&
+			    !S_ISGITLINK(ce->ce_mode)) {
+				if (!has_object_file(&ce->oid))
+					oid_array_append(&to_fetch, &ce->oid);
+			}
+		}
+		if (to_fetch.nr)
+			fetch_objects(repository_format_partial_clone,
+				      &to_fetch);
+		fetch_if_missing = fetch_if_missing_store;
+	}
 	for (i = 0; i < index->cache_nr; i++) {
 		struct cache_entry *ce = index->cache[i];
 
-- 
2.14.2.822.g60be5d43e6-goog


  parent reply index

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-29 20:11 [PATCH 00/18] Partial clone (from clone to lazy fetch in 18 patches) Jonathan Tan
2017-09-29 20:11 ` [PATCH 01/18] fsck: introduce partialclone extension Jonathan Tan
2017-09-29 20:11 ` [PATCH 02/18] fsck: support refs pointing to promisor objects Jonathan Tan
2017-09-29 20:11 ` [PATCH 03/18] fsck: support referenced " Jonathan Tan
2017-09-29 20:11 ` [PATCH 04/18] fsck: support promisor objects as CLI argument Jonathan Tan
2017-09-29 20:11 ` [PATCH 05/18] index-pack: refactor writing of .keep files Jonathan Tan
2017-09-29 20:11 ` [PATCH 06/18] introduce fetch-object: fetch one promisor object Jonathan Tan
2017-09-29 20:11 ` [PATCH 07/18] sha1_file: support lazily fetching missing objects Jonathan Tan
2017-10-12 14:42   ` Christian Couder
2017-10-12 15:45     ` Christian Couder
2017-09-29 20:11 ` [PATCH 08/18] rev-list: support termination at promisor objects Jonathan Tan
2017-09-29 20:11 ` [PATCH 09/18] gc: do not repack promisor packfiles Jonathan Tan
2017-09-29 20:11 ` [PATCH 10/18] pack-objects: rename want_.* to ignore_.* Jonathan Tan
2017-09-29 20:11 ` [PATCH 11/18] pack-objects: support --blob-max-bytes Jonathan Tan
2017-09-29 20:11 ` [PATCH 12/18] fetch-pack: support excluding large blobs Jonathan Tan
2017-09-29 20:11 ` [PATCH 13/18] fetch: refactor calculation of remote list Jonathan Tan
2017-09-29 20:11 ` [PATCH 14/18] fetch: support excluding large blobs Jonathan Tan
2017-09-29 20:11 ` [PATCH 15/18] clone: " Jonathan Tan
2017-09-29 20:11 ` [PATCH 16/18] clone: configure blobmaxbytes in created repos Jonathan Tan
2017-09-29 20:11 ` Jonathan Tan [this message]
2017-09-29 20:11 ` [PATCH 18/18] fetch-pack: restore save_commit_buffer after use Jonathan Tan
2017-09-29 21:08 ` [PATCH 00/18] Partial clone (from clone to lazy fetch in 18 patches) Johannes Schindelin
2017-10-02  4:23 ` Junio C Hamano
2017-10-03  6:15 ` Christian Couder
2017-10-03  8:50   ` Junio C Hamano
2017-10-03 14:39     ` Jeff Hostetler
2017-10-03 23:42       ` Jonathan Tan
2017-10-04 13:30         ` Jeff Hostetler

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