The object source API is getting restructured to allow plugging new
backends.
Comments?
* ps/odb-sources:
odb/source: make `begin_transaction()` function pluggable
odb/source: make `write_alternate()` function pluggable
odb/source: make `read_alternates()` function pluggable
odb/source: make `write_object_stream()` function pluggable
odb/source: make `write_object()` function pluggable
odb/source: make `freshen_object()` function pluggable
odb/source: make `for_each_object()` function pluggable
odb/source: make `read_object_stream()` function pluggable
odb/source: make `read_object_info()` function pluggable
odb/source: make `close()` function pluggable
odb/source: make `reprepare()` function pluggable
odb/source: make `free()` function pluggable
odb/source: introduce source type for robustness
odb: move reparenting logic into respective subsystems
odb: embed base source in the "files" backend
odb: introduce "files" source
odb: split `struct odb_source` into separate header
Wean the mailmap code off of the_repository dependency.
* bk/mailmap-wo-the-repository:
mailmap: drop global config variables
mailmap: stop using the_repository
Revamp object enumeration API around odb.
* ps/odb-for-each-object:
odb: drop unused `for_each_{loose,packed}_object()` functions
reachable: convert to use `odb_for_each_object()`
builtin/pack-objects: use `packfile_store_for_each_object()`
odb: introduce mtime fields for object info requests
treewide: drop uses of `for_each_{loose,packed}_object()`
treewide: enumerate promisor objects via `odb_for_each_object()`
builtin/fsck: refactor to use `odb_for_each_object()`
odb: introduce `odb_for_each_object()`
packfile: introduce function to iterate through objects
packfile: extract function to iterate through objects of a store
object-file: introduce function to iterate through objects
object-file: extract function to read object info from path
odb: fix flags parameter to be unsigned
odb: rename `FOR_EACH_OBJECT_*` flags
The "files" backend is implemented as a pointer in the `struct
odb_source`. This contradicts our typical pattern for pluggable backends
like we use it for example in the ref store or for object database
streams, where we typically embed the generic base structure in the
specialized implementation. This pattern has a couple of small benefits:
- We avoid an extra allocation.
- We hide implementation details in the generic structure.
- We can easily downcast from a generic backend to the specialized
structure and vice versa because the offsets are known at compile
time.
- It becomes trivial to identify locations where we depend on backend
specific logic because the cast needs to be explicit.
Refactor our "files" object database source to do the same and embed the
`struct odb_source` in the `struct odb_source_files`.
There are still a bunch of sites in our code base where we do have to
access internals of the "files" backend. The intent is that those will
go away over time, but this will certainly take a while. Meanwhile,
provide a `odb_source_files_downcast()` function that can convert a
generic source into a "files" source.
As we only have a single source the downcast succeeds unconditionally
for now. Eventually though the intent is to make the cast `BUG()` in
case the caller requests to downcast a non-"files" backend to a "files"
backend.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Introduce a new "files" object database source. This source encapsulates
access to both loose object files and the packfile store, similar to how
the "files" backend for refs encapsulates access to loose refs and the
packed-refs file.
Note that for now the "files" source is still a direct member of a
`struct odb_source`. This architecture will be reversed in the next
commit so that the files source contains a `struct odb_source`.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* ps/odb-for-each-object:
odb: drop unused `for_each_{loose,packed}_object()` functions
reachable: convert to use `odb_for_each_object()`
builtin/pack-objects: use `packfile_store_for_each_object()`
odb: introduce mtime fields for object info requests
treewide: drop uses of `for_each_{loose,packed}_object()`
treewide: enumerate promisor objects via `odb_for_each_object()`
builtin/fsck: refactor to use `odb_for_each_object()`
odb: introduce `odb_for_each_object()`
packfile: introduce function to iterate through objects
packfile: extract function to iterate through objects of a store
object-file: introduce function to iterate through objects
object-file: extract function to read object info from path
odb: fix flags parameter to be unsigned
odb: rename `FOR_EACH_OBJECT_*` flags
The 'read_mailmap' and 'read_mailmap_blob' functions rely on the global
'the_repository' variable. Update both functions to accept a
'struct repository' parameter.
Update all callers to pass 'the_repository' to retain the current
behavior.
Signed-off-by: Burak Kaan Karaçay <bkkaracay@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We're using `for_each_loose_object()` and `for_each_packed_object()` at
a couple of callsites to enumerate all loose and packed objects,
respectively. These functions will be removed in a subsequent commit in
favor of the newly introduced `odb_source_loose_for_each_object()` and
`packfile_store_for_each_object()` replacements.
Prepare for this by refactoring the sites accordingly.
Note that ideally, we'd convert all callsites to use the generic
`odb_for_each_object()` function already. But for some callers this is
not possible (yet), and it would require some significant refactorings
to make this work. Converting these site will thus be deferred to a
later patch series.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Rename the `FOR_EACH_OBJECT_*` flags to have an `ODB_` prefix. This
prepares us for a new upcoming `odb_for_each_object()` function and
ensures that both the function and its flags have the same prefix.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The object-info API has been cleaned up.
* ps/read-object-info-improvements:
packfile: drop repository parameter from `packed_object_info()`
packfile: skip unpacking object header for disk size requests
packfile: disentangle return value of `packed_object_info()`
packfile: always populate pack-specific info when reading object info
packfile: extend `is_delta` field to allow for "unknown" state
packfile: always declare object info to be OI_PACKED
object-file: always set OI_LOOSE when reading object info
The function `packed_object_info()` takes a packfile and offset and
returns the object info for the corresponding object. Despite these two
parameters though it also takes a repository pointer. This is redundant
information though, as `struct packed_git` already has a repository
pointer that is always populated.
Drop the redundant parameter.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit 8002e8ee18 (builtin/cat-file: use bitmaps to efficiently filter
by object type, 2025-04-02) introduced a performance regression when we
are not filtering objects: it uses bitmaps even when they won't help,
incurring extra costs. For example, running the new perf tests from this
commit, which check the performance of listing objects by oid:
$ export GIT_PERF_LARGE_REPO=/path/to/linux.git
$ git -C "$GIT_PERF_LARGE_REPO" repack -adb
$ GIT_SKIP_TESTS=p1006.1 ./run 8002e8ee18^ 8002e8ee18 p1006-cat-file.sh
[...]
Test 8002e8ee18^ 8002e8ee18
-------------------------------------------------------------------------------
1006.2: list all objects (sorted) 1.48(1.44+0.04) 6.39(6.35+0.04) +331.8%
1006.3: list all objects (unsorted) 3.01(2.97+0.04) 3.40(3.29+0.10) +13.0%
1006.4: list blobs 4.85(4.67+0.17) 1.68(1.58+0.10) -65.4%
An invocation that filters, like listing all blobs (1006.4), does
benefit from using the bitmaps; it now doesn't have to check the type of
each object from the pack data, so the tradeoff is worth it.
But for listing all objects in sorted idx order (1006.2), we otherwise
would never open the bitmap nor the revindex file. Worse, our sorting
step gets much worse. Normally we append into an array in pack .idx
order, and the sort step is trivial. But with bitmaps, we get the
objects in pack order, which is apparently random with respect to oid,
and have to sort the whole thing. (Note that this freshly-packed state
represents the best case for .idx sorting; if we had two packs, then
we'd have their objects one after the other and qsort would have to
interleave them).
The unsorted test in 1006.3 is interesting: there we are going in pack
order, so we load the revindex for the pack anyway. And though we don't
sort the result, we do use an oidset to check for duplicates. So we can
see in the 8002e8ee18^ timings that those two things cost ~1.5s over the
sorted case (mostly the oidset hash cost). We also incur the extra cost
to open the bitmap file as of 8002e8ee18, which seems to be ~400ms.
(This would probably be faster with a bitmap lookup table, but writing
that out is not yet the default).
So we know that bitmaps help when there's filtering to be done, but
otherwise make things worse. Let's only use them when there's a filter.
The perf script shows that we've fixed the regressions without hurting
the bitmap case:
Test 8002e8ee18^ 8002e8ee18 HEAD
--------------------------------------------------------------------------------------------------------
1006.2: list all objects (sorted) 1.56(1.53+0.03) 6.44(6.37+0.06) +312.8% 1.62(1.54+0.06) +3.8%
1006.3: list all objects (unsorted) 3.04(2.98+0.06) 3.45(3.38+0.07) +13.5% 3.04(2.99+0.04) +0.0%
1006.4: list blobs 5.14(4.98+0.15) 1.76(1.68+0.06) -65.8% 1.73(1.64+0.09) -66.3%
Note that there's another related case: we might have a filter that
cannot be used with bitmaps. That check is handled already for us in
for_each_bitmapped_object(), though we'd still load the bitmap and
revindex files pointlessly in that case. I don't think it can happen in
practice for cat-file, though, since it allows only blob:none,
blob:limit, and object:type filters, all of which work with bitmaps.
It would be easy-ish to insert an extra check like:
can_filter_bitmap(&opt->objects_filter);
into the conditional, but I didn't bother here. It would be redundant
with the call in for_each_bitmapped_object(), and the can_filter helper
function is static local in the bitmap code (so we'd have to make it
public).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "streaming" terminology is somewhat generic, so it may not be
immediately obvious that "streaming.{c,h}" is specific to the object
database. Rectify this by moving it into the "odb/" directory so that it
can be immediately attributed to the object subsystem.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Subsequent commits will move the backend-specific logic of object
streaming into their respective subsystems. These subsystems have gotten
rid of `the_repository` already, but we still use it in two locations in
the streaming subsystem.
Prepare for the move by fixing those two cases. Converting the logic in
`open_istream_pack_non_delta()` is trivial as we already got the object
database as input.
But for `stream_blob_to_fd()` we have to add a new parameter to make it
accessible. So, as we already have to adjust all callers anyway, rename
the function to `odb_stream_blob_to_fd()` to indicate it's part of the
object subsystem.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Two slightly different ways to get at "all the packfiles" in API
has been cleaned up.
* ps/remove-packfile-store-get-packs:
packfile: rename `packfile_store_get_all_packs()`
packfile: introduce macro to iterate through packs
packfile: drop `packfile_store_get_packs()`
builtin/grep: simplify how we preload packs
builtin/gc: convert to use `packfile_store_get_all_packs()`
object-name: convert to use `packfile_store_get_all_packs()`
We have a bunch of different sites that want to iterate through all
packs of a given `struct packfile_store`. This pattern is somewhat
verbose and repetitive, which makes it somewhat cumbersome.
Introduce a new macro `repo_for_each_pack()` that removes some of the
boilerplate.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In b0b910e052 (cat-file.c: add batch handling for submodules,
2025-06-02), we began handling submodule entries specially when batching
cat-file like so:
$ echo :sha1collisiondetection | git.compile cat-file --batch-check
855827c583bc30645ba427885caa40c5b81764d2 submodule
Commit b0b910e052 notes that submodules are handled differently than
non-existent objects, which print "<given-name> <type>", since there is
(a) no object to resolve the OID of in the first place, and as commit
b0b910e052 notes, (b) for submodules in particular, it is useful to know
what commit it points at without having to spawn another Git process.
That commit does so by calling report_object_status() and passing in
"oid_to_hex(&data->oid)" for the "obj_name" parameter. This is
unnecessary, however, since report_object_status() will do the same
automatically if given a NULL "obj_name" argument.
That behavior dates back to 6a951937ae (cat-file: add
--batch-all-objects option, 2015-06-22), so rely on that instead of
having the caller open-code that part of report_object_status().
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `get_all_packs()` function prepares the packfile store and then
returns its packfiles. Refactor it to accept a packfile store instead of
a repository to clarify its scope.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Reduce implicit assumption and dependence on the_repository in the
object-file subsystem.
* ps/object-file-wo-the-repository:
object-file: get rid of `the_repository` in index-related functions
object-file: get rid of `the_repository` in `force_object_loose()`
object-file: get rid of `the_repository` in `read_loose_object()`
object-file: get rid of `the_repository` in loose object iterators
object-file: remove declaration for `for_each_file_in_obj_subdir()`
object-file: inline `for_each_loose_file_in_objdir_buf()`
object-file: get rid of `the_repository` when writing objects
odb: introduce `odb_write_object()`
loose: write loose objects map via their source
object-file: get rid of `the_repository` in `finalize_object_file()`
object-file: get rid of `the_repository` in `loose_object_info()`
object-file: get rid of `the_repository` when freshening objects
object-file: inline `check_and_freshen()` functions
object-file: get rid of `the_repository` in `has_loose_object()`
object-file: stop using `the_hash_algo`
object-file: fix -Wsign-compare warnings
In 036876a106 (config: hide functions using `the_repository` by
default, 2024-08-13) we have moved around a bunch of functions in the
config subsystem that depend on `the_repository`. Those function have
been converted into mere wrappers around their equivalent function that
takes in a repository as parameter, and the intent was that we'll
eventually remove those wrappers to make the dependency on the global
repository variable explicit at the callsite.
Follow through with that intent and remove `git_config()`. All callsites
are adjusted so that they use `repo_config(the_repository, ...)`
instead. While some callsites might already have a repository available,
this mechanical conversion is the exact same as the current situation
and thus cannot cause any regression. Those sites should eventually be
cleaned up in a later patch series.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The iterators for loose objects still rely on `the_repository`. Refactor
them:
- `for_each_loose_file_in_objdir()` is refactored so that the caller
is now expected to pass an `odb_source` as parameter instead of the
path to that source. Furthermore, it is renamed accordingly to
`for_each_loose_file_in_source()`.
- `for_each_loose_object()` is refactored to take in an object
database now and calls the above function in a loop.
This allows us to get rid of the global dependency.
Adjust callers accordingly.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Code clean-up around object access API.
* ps/object-store:
odb: rename `read_object_with_reference()`
odb: rename `pretend_object_file()`
odb: rename `has_object()`
odb: rename `repo_read_object_file()`
odb: rename `oid_object_info()`
odb: trivial refactorings to get rid of `the_repository`
odb: get rid of `the_repository` when handling submodule sources
odb: get rid of `the_repository` when handling the primary source
odb: get rid of `the_repository` in `for_each()` functions
odb: get rid of `the_repository` when handling alternates
odb: get rid of `the_repository` in `odb_mkstemp()`
odb: get rid of `the_repository` in `assert_oid_type()`
odb: get rid of `the_repository` in `find_odb()`
odb: introduce parent pointers
object-store: rename files to "odb.{c,h}"
object-store: rename `object_directory` to `odb_source`
object-store: rename `raw_object_store` to `object_database`
* ps/object-store:
odb: rename `read_object_with_reference()`
odb: rename `pretend_object_file()`
odb: rename `has_object()`
odb: rename `repo_read_object_file()`
odb: rename `oid_object_info()`
odb: trivial refactorings to get rid of `the_repository`
odb: get rid of `the_repository` when handling submodule sources
odb: get rid of `the_repository` when handling the primary source
odb: get rid of `the_repository` in `for_each()` functions
odb: get rid of `the_repository` when handling alternates
odb: get rid of `the_repository` in `odb_mkstemp()`
odb: get rid of `the_repository` in `assert_oid_type()`
odb: get rid of `the_repository` in `find_odb()`
odb: introduce parent pointers
object-store: rename files to "odb.{c,h}"
object-store: rename `object_directory` to `odb_source`
object-store: rename `raw_object_store` to `object_database`
Rename `read_object_with_reference()` to `odb_read_object_peeled()` to
match other functions related to the object database and our modern
coding guidelines. Furthermore though, the old name didn't really
describe very well what this function actually does, which is to walk
down any commit and tag objects until an object of the required type has
been found. This is generally referred to as "peeling", so the new name
should be way more descriptive.
No compatibility wrapper is introduced as the function is not used a lot
throughout our codebase.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Rename `has_object()` to `odb_has_object()` to match other functions
related to the object database and our modern coding guidelines.
Introduce a compatibility wrapper so that any in-flight topics will
continue to compile.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Rename `repo_read_object_file()` to `odb_read_object()` to match other
functions related to the object database and our modern coding
guidelines.
Introduce a compatibility wrapper so that any in-flight topics will
continue to compile.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Rename `oid_object_info()` to `odb_read_object_info()` as well as their
`_extended()` variant to match other functions related to the object
database and our modern coding guidelines.
Introduce compatibility wrappers so that any in-flight topics will
continue to compile.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the preceding commits we have renamed the structures contained in
"object-store.h" to `struct object_database` and `struct odb_backend`.
As such, the code files "object-store.{c,h}" are confusingly named now.
Rename them to "odb.{c,h}" accordingly.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When an object specification is passed to 'cat-file --batch[-check]'
referring to a submodule (e.g. 'HEAD:path/to/my/submodule'), the current
behavior of the command is to print the "missing" error message. However, it
is often valuable for callers to distinguish between paths that are actually
missing and "the submodule tree entry exists, but the object does not exist
in the repository".
To disambiguate without needing to invoke a separate Git process (e.g.
'ls-tree'), print the message "<oid> submodule" for such objects instead of
"<object> missing". In addition to the change from "missing" to "submodule",
the new message differs from the old in that it always prints the resolved
tree entry's OID, rather than the input object specification.
Note that this implementation maintains a distinction between submodules
where the commit OID is not present in the repo, and submodules where the
commit OID *is* present; the former will now print "<object> submodule", but
the latter will still print the full object content.
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a formatting atom, used with the --batch-check/--batch-command options,
that prints the octal representation of the object mode if a given revision
includes that information, e.g. one that follows the format
<tree-ish>:<path>. If the mode information does not exist, an empty string
is printed instead.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that we no longer support OBJECT_INFO_ALLOW_UNKNOWN_TYPE, there is
no need to pass a strbuf into oid_object_info_extended() to record the
type. The regular object_type enum is sufficient to capture all of the
types we will allow.
This simplifies the code a bit, and will eventually let us drop
object_info's type_name strbuf support.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The cat-file command has some minor support for handling objects with
"unknown" types. I.e., strings that are not "blob", "commit", "tree", or
"tag".
In theory this could be used for debugging or experimenting with
extensions to Git. But in practice this support is not very useful:
1. You can get the type and size of such objects, but nothing else.
Not even the contents!
2. Only loose objects are supported, since packfiles use numeric ids
for the types, rather than strings.
3. Likewise you cannot ever transfer objects between repositories,
because they cannot be represented in the packfiles used for the
on-the-wire protocol.
The support for these unknown types complicates the object-parsing code,
and has led to bugs such as b748ddb7a4 (unpack_loose_header(): fix
infinite loop on broken zlib input, 2025-02-25). So let's drop it.
The first step is to remove the user-facing parts, which are accessible
only via cat-file. This is technically backwards-incompatible, but given
the limitations listed above, these objects couldn't possibly be useful
in any workflow.
However, we can't just rip out the option entirely. That would hurt a
caller who ran:
git cat-file -t --allow-unknown-object <oid>
and fed it normal, well-formed objects. There --allow-unknown-type was
doing nothing, but we wouldn't want to start bailing with an error. So
to protect any such callers, we'll retain --allow-unknown-type as a
noop.
The code change is fairly small (but we'll able to clean up more code in
follow-on patches). The test updates drop any use of the option. We
still retain tests that feed the broken objects to cat-file without
--allow-unknown-type, as we should continue to confirm that those
objects are rejected. Note that in one spot we can drop a layer of loop,
re-indenting the body; viewing the diff with "-w" helps there.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As the comment of `repo_has_object_file()` and its `_with_flags()`
variant tells us, these functions are considered to be deprecated in
favor of `has_object()`. There are a couple of slight benefits in favor
of the replacement:
- The new function has a short-and-sweet name.
- More explicit defaults: `has_object()` doesn't fetch missing objects
via promisor remotes, and neither does it reload packfiles if an
object wasn't found by default. This ensures that it becomes
immediately obvious when a simple object existence check may result
in expensive actions.
Most importantly though, it is confusing that we have two sets of
functions that ultimately do the same thing, but with different
defaults.
Start sunsetting `repo_has_object_file()` and its `_with_flags()`
sibling by replacing all callsites with `has_object()`:
- `repo_has_object_file(...)` is equivalent to
`has_object(..., HAS_OBJECT_RECHECK_PACKED | HAS_OBJECT_FETCH_PROMISOR)`.
- `repo_has_object_file_with_flags(..., OBJECT_INFO_QUICK | OBJECT_INFO_SKIP_FETCH_OBJECT)`
is equivalent to `has_object(..., 0)`.
- `repo_has_object_file_with_flags(..., OBJECT_INFO_SKIP_FETCH_OBJECT)`
is equivalent to `has_object(..., HAS_OBJECT_RECHECK_PACKED)`.
- `repo_has_object_file_with_flags(..., OBJECT_INFO_QUICK)`
is equivalent to `has_object(..., HAS_OBJECT_FETCH_PROMISOR)`.
The replacements should be functionally equivalent.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* ps/object-file-cleanup:
object-store: merge "object-store-ll.h" and "object-store.h"
object-store: remove global array of cached objects
object: split out functions relating to object store subsystem
object-file: drop `index_blob_stream()`
object-file: split up concerns of `HASH_*` flags
object-file: split out functions relating to object store subsystem
object-file: move `xmmap()` into "wrapper.c"
object-file: move `git_open_cloexec()` to "compat/open.c"
object-file: move `safe_create_leading_directories()` into "path.c"
object-file: move `mkdir_in_gitdir()` into "path.c"
The "object-store-ll.h" header has been introduced to keep transitive
header dependendcies and compile times at bay. Now that we have created
a new "object-store.c" file though we can easily move the last remaining
additional bit of "object-store.h", the `odb_path_map`, out of the
header.
Do so. As the "object-store.h" header is now equivalent to its low-level
alternative we drop the latter and inline it into the former.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
While it is now possible to filter objects by type, this mechanism is
for now mostly a convenience. Most importantly, we still have to iterate
through the whole packfile to find all objects of a specific type. This
can be prohibitively expensive depending on the size of the packfiles.
It isn't really possible to do better than this when only considering a
packfile itself, as the order of objects is not fixed. But when we have
a packfile with a corresponding bitmap, either because the packfile
itself has one or because the multi-pack index has a bitmap for it, then
we can use these bitmaps to improve the runtime.
While bitmaps are typically used to compute reachability of objects,
they also contain one bitmap per object type that encodes which object
has what type. So instead of reading through the whole packfile(s), we
can use the bitmaps and iterate through the type-specific bitmap.
Typically, only a subset of packfiles will have a bitmap. But this isn't
really much of a problem: we can use bitmaps when available, and then
use the non-bitmap walk for every packfile that isn't covered by one.
Overall, this leads to quite a significant speedup depending on how many
objects of a certain type exist. The following benchmarks have been
executed in the Chromium repository, which has a 50GB packfile with
almost 25 million objects. As expected, there isn't really much of a
change in performance without an object filter:
Benchmark 1: cat-file with no-filter (revision = HEAD~)
Time (mean ± σ): 89.675 s ± 4.527 s [User: 40.807 s, System: 10.782 s]
Range (min … max): 83.052 s … 96.084 s 10 runs
Benchmark 2: cat-file with no-filter (revision = HEAD)
Time (mean ± σ): 88.991 s ± 2.488 s [User: 42.278 s, System: 10.305 s]
Range (min … max): 82.843 s … 91.271 s 10 runs
Summary
cat-file with no-filter (revision = HEAD) ran
1.01 ± 0.06 times faster than cat-file with no-filter (revision = HEAD~)
We still have to scan through all objects as we yield all of them, so
using the bitmap in this case doesn't really buy us anything. What is
noticeable in this benchmark is that we're I/O-bound, not CPU-bound, as
can be seen from the user/system runtimes, which combined are way lower
than the overall benchmarked runtime.
But when we do use a filter we can see a significant improvement:
Benchmark 1: cat-file with filter=object:type=commit (revision = HEAD~)
Time (mean ± σ): 86.444 s ± 4.081 s [User: 36.830 s, System: 11.312 s]
Range (min … max): 80.305 s … 93.104 s 10 runs
Benchmark 2: cat-file with filter=object:type=commit (revision = HEAD)
Time (mean ± σ): 2.089 s ± 0.015 s [User: 1.872 s, System: 0.207 s]
Range (min … max): 2.073 s … 2.119 s 10 runs
Summary
cat-file with filter=object:type=commit (revision = HEAD) ran
41.38 ± 1.98 times faster than cat-file with filter=object:type=commit (revision = HEAD~)
This is because we don't have to scan through all packfiles anymore, but
can instead directly look up relevant objects.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Pull out a common function that allows us to iterate over all objects in
a repository. Right now the logic is trivial and would only require two
function calls, making this refactoring a bit pointless. But in the next
commit we will iterate on this logic to make use of bitmaps, so this is
about to become a bit more complex.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Implement support for the "object:type=" filter in git-cat-file(1),
which causes us to omit all objects that don't match the provided object
type.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Implement support for the "blob:limit=" filter in git-cat-file(1), which
causes us to omit all blobs that are bigger than a certain size.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Implement support for the "blob:none" filter in git-cat-file(1), which
causes us to omit all blobs.
Note that this new filter requires us to read the object type via
`oid_object_info_extended()` in `batch_object_write()`. But as we try to
optimize away reading objects from the database the `data->info.typep`
pointer may not be set. We thus have to adapt the logic to conditionally
set the pointer in cases where the filter is given.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In batch mode, git-cat-file(1) enumerates all objects and prints them
by iterating through both loose and packed objects. This works without
considering their reachability at all, and consequently most options to
filter objects as they exist in e.g. git-rev-list(1) are not applicable.
In some situations it may still be useful though to filter objects based
on properties that are inherent to them. This includes the object size
as well as its type.
Such a filter already exists in git-rev-list(1) with the `--filter=`
command line option. While this option supports a couple of filters that
are not applicable to our usecase, some of them are quite a neat fit.
Wire up the filter as an option for git-cat-file(1). This allows us to
reuse the same syntax as in git-rev-list(1) so that we don't have to
reinvent the wheel. For now, we die when any of the filter options has
been passed by the user, but they will be wired up in subsequent
commits.
Further note that the filters that we are about to introduce don't
significantly speed up the runtime of git-cat-file(1). While we can skip
emitting a lot of objects in case they are uninteresting to us, the
majority of time is spent reading the packfile, which is bottlenecked by
I/O and not the processor. This will change though once we start to make
use of bitmaps, which will allow us to skip reading the whole packfile.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We have multiple callsites that report the status of an object, for
example when the objec tis missing or its name is ambiguous. We're about
to add a couple more such callsites to report on "excluded" objects.
Prepare for this by introducing a new function `report_object_status()`
that encapsulates the functionality.
Note that this function also flushes stdout, which is a requirement so
that request-response style batched modes can learn about the status
before proceeding to the next object. We already flush correctly at all
existing callsites, even though the flush in `batch_one_object()` only
comes after the switch statement. That flush is now redundant, and we
could in theory deduplicate it by moving it into all branches that don't
use `report_object_status()`. But that doesn't quite feel sensible:
- The duplicate flush should ultimately just be a no-op for us and
thus shouldn't impact performance significantly.
- By keeping the flush in `report_object_status()` we ensure that all
future callers get semantics correct.
So let's just be pragmatic and live with the duplicated flush.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The usage strings for git-cat-file(1) that we pass to `parse_options()`
and `usage_msg_optf()` are stored in a variable called `usage`. This
variable shadows the declaration of `usage()`, which we'll want to use
in a subsequent commit.
Rename the variable to `builtin_catfile_usage`, which is in line with
how the variable is typically called in other builtins.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Start working to make the codebase buildable with -Wsign-compare.
* ps/build-sign-compare:
t/helper: don't depend on implicit wraparound
scalar: address -Wsign-compare warnings
builtin/patch-id: fix type of `get_one_patchid()`
builtin/blame: fix type of `length` variable when emitting object ID
gpg-interface: address -Wsign-comparison warnings
daemon: fix type of `max_connections`
daemon: fix loops that have mismatching integer types
global: trivial conversions to fix `-Wsign-compare` warnings
pkt-line: fix -Wsign-compare warning on 32 bit platform
csum-file: fix -Wsign-compare warning on 32-bit platform
diff.h: fix index used to loop through unsigned integer
config.mak.dev: drop `-Wno-sign-compare`
global: mark code units that generate warnings with `-Wsign-compare`
compat/win32: fix -Wsign-compare warning in "wWinMain()"
compat/regex: explicitly ignore "-Wsign-compare" warnings
git-compat-util: introduce macros to disable "-Wsign-compare" warnings
Mark code units that generate warnings with `-Wsign-compare`. This
allows for a structured approach to get rid of all such warnings over
time in a way that can be easily measured.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The function `for_each_packed_object` currently relies on the global
variable `the_repository`. To eliminate global variable usage in
`packfile.c`, we should progressively shift the dependency on
the_repository to higher layers. Let's remove its usage from this
function and closely related function `is_promisor_object`.
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The convention to calling into built-in command implementation has
been updated to pass the repository, if known, together with the
prefix value.
* jc/pass-repo-to-builtins:
add: pass in repo variable instead of global the_repository
builtin: remove USE_THE_REPOSITORY for those without the_repository
builtin: remove USE_THE_REPOSITORY_VARIABLE from builtin.h
builtin: add a repository parameter for builtin functions
Instead of including USE_THE_REPOSITORY_VARIABLE by default on every
builtin, remove it from builtin.h and add it to all the builtins that
include builtin.h (by definition, that means all builtins/*.c).
Also, remove the include statement for repository.h since it gets
brought in through builtin.h.
The next step will be to migrate each builtin
from having to use the_repository.
Signed-off-by: John Cai <johncai86@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
