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2021-02-22packfile: introduce 'find_kept_pack_entry()'Libravatar Taylor Blau1-0/+5
Future callers will want a function to fill a 'struct pack_entry' for a given object id but _only_ from its position in any kept pack(s). In particular, an new 'git repack' mode which ensures the resulting packs form a geometric progress by object count will mark packs that it does not want to repack as "kept in-core", and it will want to halt a reachability traversal as soon as it visits an object in any of the kept packs. But, it does not want to halt the traversal at non-kept, or .keep packs. The obvious alternative is 'find_pack_entry()', but this doesn't quite suffice since it only returns the first pack it finds, which may or may not be kept (and the mru cache makes it unpredictable which one you'll get if there are options). Short of that, you could walk over all packs looking for the object in each one, but it scales with the number of packs, which may be prohibitive. Introduce 'find_kept_pack_entry()', a function which is like 'find_pack_entry()', but only fills in objects in the kept packs. Handle packs which have .keep files, as well as in-core kept packs separately, since certain callers will want to distinguish one from the other. (Though on-disk and in-core kept packs share the adjective "kept", it is best to think of the two sets as independent.) There is a gotcha when looking up objects that are duplicated in kept and non-kept packs, particularly when the MIDX stores the non-kept version and the caller asked for kept objects only. This could be resolved by teaching the MIDX to resolve duplicates by always favoring the kept pack (if one exists), but this breaks an assumption in existing MIDXs, and so it would require a format change. The benefit to changing the MIDX in this way is marginal, so we instead have a more thorough check here which is explained with a comment. Callers will be added in subsequent patches. Co-authored-by: Jeff King <peff@peff.net> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Taylor Blau <me@ttaylorr.com> Reviewed-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-25packfile: prepare for the existence of '*.rev' filesLibravatar Taylor Blau1-0/+1
Specify the format of the on-disk reverse index 'pack-*.rev' file, as well as prepare the code for the existence of such files. The reverse index maps from pack relative positions (i.e., an index into the array of object which is sorted by their offsets within the packfile) to their position within the 'pack-*.idx' file. Today, this is done by building up a list of (off_t, uint32_t) tuples for each object (the off_t corresponding to that object's offset, and the uint32_t corresponding to its position in the index). To convert between pack and index position quickly, this array of tuples is radix sorted based on its offset. This has two major drawbacks: First, the in-memory cost scales linearly with the number of objects in a pack. Each 'struct revindex_entry' is sizeof(off_t) + sizeof(uint32_t) + padding bytes for a total of 16. To observe this, force Git to load the reverse index by, for e.g., running 'git cat-file --batch-check="%(objectsize:disk)"'. When asking for a single object in a fresh clone of the kernel, Git needs to allocate 120+ MB of memory in order to hold the reverse index in memory. Second, the cost to sort also scales with the size of the pack. Luckily, this is a linear function since 'load_pack_revindex()' uses a radix sort, but this cost still must be paid once per pack per process. As an example, it takes ~60x longer to print the _size_ of an object as it does to print that entire object's _contents_: Benchmark #1: git.compile cat-file --batch <obj Time (mean ± σ): 3.4 ms ± 0.1 ms [User: 3.3 ms, System: 2.1 ms] Range (min … max): 3.2 ms … 3.7 ms 726 runs Benchmark #2: git.compile cat-file --batch-check="%(objectsize:disk)" <obj Time (mean ± σ): 210.3 ms ± 8.9 ms [User: 188.2 ms, System: 23.2 ms] Range (min … max): 193.7 ms … 224.4 ms 13 runs Instead, avoid computing and sorting the revindex once per process by writing it to a file when the pack itself is generated. The format is relatively straightforward. It contains an array of uint32_t's, the length of which is equal to the number of objects in the pack. The ith entry in this table contains the index position of the ith object in the pack, where "ith object in the pack" is determined by pack offset. One thing that the on-disk format does _not_ contain is the full (up to) eight-byte offset corresponding to each object. This is something that the in-memory revindex contains (it stores an off_t in 'struct revindex_entry' along with the same uint32_t that the on-disk format has). Omit it in the on-disk format, since knowing the index position for some object is sufficient to get a constant-time lookup in the pack-*.idx file to ask for an object's offset within the pack. This trades off between the on-disk size of the 'pack-*.rev' file for runtime to chase down the offset for some object. Even though the lookup is constant time, the constant is heavier, since it can potentially involve two pointer walks in v2 indexes (one to access the 4-byte offset table, and potentially a second to access the double wide offset table). Consider trying to map an object's pack offset to a relative position within that pack. In a cold-cache scenario, more page faults occur while switching between binary searching through the reverse index and searching through the *.idx file for an object's offset. Sure enough, with a cold cache (writing '3' into '/proc/sys/vm/drop_caches' after 'sync'ing), printing out the entire object's contents is still marginally faster than printing its size: Benchmark #1: git.compile cat-file --batch-check="%(objectsize:disk)" <obj >/dev/null Time (mean ± σ): 22.6 ms ± 0.5 ms [User: 2.4 ms, System: 7.9 ms] Range (min … max): 21.4 ms … 23.5 ms 41 runs Benchmark #2: git.compile cat-file --batch <obj >/dev/null Time (mean ± σ): 17.2 ms ± 0.7 ms [User: 2.8 ms, System: 5.5 ms] Range (min … max): 15.6 ms … 18.2 ms 45 runs (Numbers taken in the kernel after cheating and using the next patch to generate a reverse index). There are a couple of approaches to improve cold cache performance not pursued here: - We could include the object offsets in the reverse index format. Predictably, this does result in fewer page faults, but it triples the size of the file, while simultaneously duplicating a ton of data already available in the .idx file. (This was the original way I implemented the format, and it did show `--batch-check='%(objectsize:disk)'` winning out against `--batch`.) On the other hand, this increase in size also results in a large block-cache footprint, which could potentially hurt other workloads. - We could store the mapping from pack to index position in more cache-friendly way, like constructing a binary search tree from the table and writing the values in breadth-first order. This would result in much better locality, but the price you pay is trading O(1) lookup in 'pack_pos_to_index()' for an O(log n) one (since you can no longer directly index the table). So, neither of these approaches are taken here. (Thankfully, the format is versioned, so we are free to pursue these in the future.) But, cold cache performance likely isn't interesting outside of one-off cases like asking for the size of an object directly. In real-world usage, Git is often performing many operations in the revindex (i.e., asking about many objects rather than a single one). The trade-off is worth it, since we will avoid the vast majority of the cost of generating the revindex that the extra pointer chase will look like noise in the following patch's benchmarks. This patch describes the format and prepares callers (like in pack-revindex.c) to be able to read *.rev files once they exist. An implementation of the writer will appear in the next patch, and callers will gradually begin to start using the writer in the patches that follow after that. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-28midx: traverse the local MIDX firstLibravatar Taylor Blau1-0/+1
When a repository has an alternate object directory configured, callers can traverse through each alternate's MIDX by walking the '->next' pointer. But, when 'prepare_multi_pack_index_one()' loads multiple MIDXs, it places the new ones at the front of this pointer chain, not at the end. This can be confusing for callers such as 'git repack -ad', causing test failures like in t7700.6 with 'GIT_TEST_MULTI_PACK_INDEX=1'. The occurs when dropping a pack known to the local MIDX with alternates configured that have their own MIDX. Since the alternate's MIDX is returned via 'get_multi_pack_index()', 'midx_contains_pack()' returns true (which is correct, since it traverses through the '->next' pointer to find the MIDX in the chain that does contain the requested object). But, we call 'clear_midx_file()' on 'the_repository', which drops the MIDX at the path of the first MIDX in the chain, which (in the case of t7700.6 is the one in the alternate). This patch addresses that by: - placing the local MIDX first in the chain when calling 'prepare_multi_pack_index_one()', and - introducing a new 'get_local_multi_pack_index()', which explicitly returns the repository-local MIDX, if any. Don't impose an additional order on the MIDX's '->next' pointer beyond that the first item in the chain must be local if one exists so that we avoid a quadratic insertion. Likewise, use 'get_local_multi_pack_index()' in 'remove_redundant_pack()' to fix the formerly broken t7700.6 when run with 'GIT_TEST_MULTI_PACK_INDEX=1'. Finally, note that the MIDX ordering invariant is only preserved by the insertion order in 'prepare_packed_git()', which traverses through the ODB's '->next' pointer, meaning we visit the local object store first. This fragility makes this an undesirable long-term solution if more callers are added, but it is acceptable for now since this is the only caller. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-24packfile: drop nth_packed_object_sha1()Libravatar Jeff King1-9/+3
Once upon a time, nth_packed_object_sha1() was the primary way to get the oid of a packfile's index position. But these days we have the more type-safe nth_packed_object_id() wrapper, and all callers have been converted. Let's drop the "sha1" version (turning the safer wrapper into a single function) so that nobody is tempted to introduce new callers. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-24nth_packed_object_oid(): use customary integer returnLibravatar Jeff King1-3/+2
Our nth_packed_object_sha1() function returns NULL for error. So when we wrapped it with nth_packed_object_oid(), we kept the same semantics. But it's a bit funny, because the caller actually passes in an out parameter, and the pointer we return is just that same struct they passed to us (or NULL). It's not too terrible, but it does make the interface a little non-idiomatic. Let's switch to our usual "0 for success, negative for error" return value. Most callers either don't check it, or are trivially converted. The one that requires the biggest change is actually improved, as we can ditch an extra aliased pointer variable. Since we are changing the interface in a subtle way that the compiler wouldn't catch, let's also change the name to catch any topics in flight. We can drop the 'o' and make it nth_packed_object_id(). That's slightly shorter, but also less redundant since the 'o' stands for "object" already. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-14Merge branch 'jk/packfile-reuse-cleanup'Libravatar Junio C Hamano1-0/+3
The way "git pack-objects" reuses objects stored in existing pack to generate its result has been improved. * jk/packfile-reuse-cleanup: pack-bitmap: don't rely on bitmap_git->reuse_objects pack-objects: add checks for duplicate objects pack-objects: improve partial packfile reuse builtin/pack-objects: introduce obj_is_packed() pack-objects: introduce pack.allowPackReuse csum-file: introduce hashfile_total() pack-bitmap: simplify bitmap_has_oid_in_uninteresting() pack-bitmap: uninteresting oid can be outside bitmapped packfile pack-bitmap: introduce bitmap_walk_contains() ewah/bitmap: introduce bitmap_word_alloc() packfile: expose get_delta_base() builtin/pack-objects: report reused packfile objects
2019-09-13packfile: expose get_delta_base()Libravatar Jeff King1-0/+3
In a following commit get_delta_base() will be used outside packfile.c, so let's make it non static and declare it in packfile.h. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-09-09Merge branch 'ds/midx-expire-repack'Libravatar Junio C Hamano1-1/+1
Code cleanup. * ds/midx-expire-repack: packfile.h: drop extern from function declaration
2019-08-20packfile.h: drop extern from function declarationLibravatar Denton Liu1-1/+1
In 336226c259 (packfile.h: drop extern from function declarations, 2019-04-05), `extern` was removed from function declarations because it's redundant. However, in 8434e85d5f (repack: refactor pack deletion for future use, 2019-06-10), an `extern` was mistakenly included. Remove this spurious `extern`. Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-07-19Merge branch 'ds/midx-expire-repack'Libravatar Junio C Hamano1-0/+7
"git multi-pack-index" learned expire and repack subcommands. * ds/midx-expire-repack: t5319: use 'test-tool path-utils' instead of 'ls -l' t5319-multi-pack-index.sh: test batch size zero midx: add test that 'expire' respects .keep files multi-pack-index: test expire while adding packs midx: implement midx_repack() multi-pack-index: prepare 'repack' subcommand multi-pack-index: implement 'expire' subcommand midx: refactor permutation logic and pack sorting midx: simplify computation of pack name lengths multi-pack-index: prepare for 'expire' subcommand Docs: rearrange subcommands for multi-pack-index repack: refactor pack deletion for future use
2019-07-09Merge branch 'ds/close-object-store'Libravatar Junio C Hamano1-1/+1
The commit-graph file is now part of the "files that the runtime may keep open file descriptors on, all of which would need to be closed when done with the object store", and the file descriptor to an existing commit-graph file now is closed before "gc" finalizes a new instance to replace it. * ds/close-object-store: packfile: rename close_all_packs to close_object_store packfile: close commit-graph in close_all_packs commit-graph: use raw_object_store when closing
2019-06-12packfile: rename close_all_packs to close_object_storeLibravatar Derrick Stolee1-1/+1
The close_all_packs() method is now responsible for more than just pack-files. It also closes the commit-graph and the multi-pack-index. Rename the function to be more descriptive of its larger role. The name also fits because the input parameter is a raw_object_store. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-11repack: refactor pack deletion for future useLibravatar Derrick Stolee1-0/+7
The repack builtin deletes redundant pack-files and their associated .idx, .promisor, .bitmap, and .keep files. We will want to re-use this logic in the future for other types of repack, so pull the logic into 'unlink_pack_path()' in packfile.c. The 'ignore_keep' parameter is enabled for the use in repack, but will be important for a future caller. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-05-09Merge branch 'nd/sha1-name-c-wo-the-repository'Libravatar Junio C Hamano1-1/+2
Further code clean-up to allow the lowest level of name-to-object mapping layer to work with a passed-in repository other than the default one. * nd/sha1-name-c-wo-the-repository: (34 commits) sha1-name.c: remove the_repo from get_oid_mb() sha1-name.c: remove the_repo from other get_oid_* sha1-name.c: remove the_repo from maybe_die_on_misspelt_object_name submodule-config.c: use repo_get_oid for reading .gitmodules sha1-name.c: add repo_get_oid() sha1-name.c: remove the_repo from get_oid_with_context_1() sha1-name.c: remove the_repo from resolve_relative_path() sha1-name.c: remove the_repo from diagnose_invalid_index_path() sha1-name.c: remove the_repo from handle_one_ref() sha1-name.c: remove the_repo from get_oid_1() sha1-name.c: remove the_repo from get_oid_basic() sha1-name.c: remove the_repo from get_describe_name() sha1-name.c: remove the_repo from get_oid_oneline() sha1-name.c: add repo_interpret_branch_name() sha1-name.c: remove the_repo from interpret_branch_mark() sha1-name.c: remove the_repo from interpret_nth_prior_checkout() sha1-name.c: remove the_repo from get_short_oid() sha1-name.c: add repo_for_each_abbrev() sha1-name.c: store and use repo in struct disambiguate_state sha1-name.c: add repo_find_unique_abbrev_r() ...
2019-04-25Merge branch 'jk/server-info-rabbit-hole'Libravatar Junio C Hamano1-41/+47
Code clean-up around a much-less-important-than-it-used-to-be update_server_info() funtion. * jk/server-info-rabbit-hole: update_info_refs(): drop unused force parameter server-info: drop objdirlen pointer arithmetic server-info: drop nr_alloc struct member server-info: use strbuf to read old info/packs file server-info: simplify cleanup in parse_pack_def() server-info: fix blind pointer arithmetic http: simplify parsing of remote objects/info/packs packfile: fix pack basename computation midx: check both pack and index names for containment t5319: drop useless --buffer from cat-file t5319: fix bogus cat-file argument pack-revindex: open index if necessary packfile.h: drop extern from function declarations
2019-04-16packfile: fix pack basename computationLibravatar Jeff King1-0/+6
When we have a multi-pack-index that covers many packfiles, we try to avoid opening the .idx for those packfiles. To do that we feed the pack name to midx_contains_pack(). But that function wants to see only the basename, which we compute using strrchr() to find the final slash. But that leaves an extra "/" at the start of our string. We can fix this by incrementing the pointer. That also raises the question of what to do when the name does not have a '/' at all. This should generally not happen (we always find files in "pack/"), but it doesn't hurt to be defensive here. Let's wrap all of that up in a helper function and make it publicly available, since a later patch will need to use it, too. The tests don't notice because there's nothing about opening those .idx files that would cause us to give incorrect output. It's just a little slower. The new test checks this case by corrupting the covered .idx, and then making sure we don't complain about it. We also have to tweak t5570, which intentionally corrupts a .idx file and expects us to notice it. When run with GIT_TEST_MULTI_PACK_INDEX, this will fail since we now will (correctly) not bother opening the .idx at all. We can fix that by unconditionally dropping any midx that's there, which ensures we'll have to read the .idx. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-16packfile.h: drop extern from function declarationsLibravatar Jeff King1-41/+41
As CodingGuidelines recommends, we do not need an "extern" when declaring a public function. Let's drop these. Note that we leave the extern on report_garbage(), as that is actually a function pointer, not a function itself. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-08packfile.c: add repo_approximate_object_count()Libravatar Nguyễn Thái Ngọc Duy1-1/+2
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-22midx: during verify group objects by packfile to speed verificationLibravatar Jeff Hostetler1-0/+2
Teach `multi-pack-index verify` to sort the set of object by packfile so that only one packfile needs to be open at a time. This is a performance improvement. Previously, objects were verified in OID order. This essentially requires all packfiles to be open at the same time. If the number of packfiles exceeds the open file limit, packfiles would be LRU-closed and re-opened many times. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-02-05Merge branch 'sb/more-repo-in-api'Libravatar Junio C Hamano1-1/+1
The in-core repository instances are passed through more codepaths. * sb/more-repo-in-api: (23 commits) t/helper/test-repository: celebrate independence from the_repository path.h: make REPO_GIT_PATH_FUNC repository agnostic commit: prepare free_commit_buffer and release_commit_memory for any repo commit-graph: convert remaining functions to handle any repo submodule: don't add submodule as odb for push submodule: use submodule repos for object lookup pretty: prepare format_commit_message to handle arbitrary repositories commit: prepare logmsg_reencode to handle arbitrary repositories commit: prepare repo_unuse_commit_buffer to handle any repo commit: prepare get_commit_buffer to handle any repo commit-reach: prepare in_merge_bases[_many] to handle any repo commit-reach: prepare get_merge_bases to handle any repo commit-reach.c: allow get_merge_bases_many_0 to handle any repo commit-reach.c: allow remove_redundant to handle any repo commit-reach.c: allow merge_bases_many to handle any repo commit-reach.c: allow paint_down_to_common to handle any repo commit: allow parse_commit* to handle any repo object: parse_object to honor its repository argument object-store: prepare has_{sha1, object}_file to handle any repo object-store: prepare read_object_file to deal with any repo ...
2018-10-19packfile: allow has_packed_and_bad to handle arbitrary repositoriesLibravatar Stefan Beller1-1/+1
has_packed_and_bad is not widely used, so just migrate it all at once. Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-10-15fuzz: add fuzz testing for packfile indices.Libravatar Josh Steadmon1-0/+13
Breaks the majority of check_packed_git_idx() into a separate function, load_idx(). The latter function operates on arbitrary buffers, which makes it suitable as a fuzzing test target. Signed-off-by: Josh Steadmon <steadmon@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-20packfile: add all_packs listLibravatar Derrick Stolee1-0/+1
If a repo contains a multi-pack-index, then the packed_git list does not contain the packfiles that are covered by the multi-pack-index. This is important for doing object lookups, abbreviations, and approximating object count. However, there are many operations that really want to iterate over all packfiles. Create a new 'all_packs' linked list that contains this list, starting with the packfiles in the multi-pack-index and then continuing along the packed_git linked list. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-20Sync 'ds/multi-pack-index' to v2.19.0-rc0Libravatar Junio C Hamano1-0/+9
* ds/multi-pack-index: (23 commits) midx: clear midx on repack packfile: skip loading index if in multi-pack-index midx: prevent duplicate packfile loads midx: use midx in approximate_object_count midx: use existing midx when writing new one midx: use midx in abbreviation calculations midx: read objects from multi-pack-index config: create core.multiPackIndex setting midx: write object offsets midx: write object id fanout chunk midx: write object ids in a chunk midx: sort and deduplicate objects from packfiles midx: read pack names into array multi-pack-index: write pack names in chunk multi-pack-index: read packfile list packfile: generalize pack directory list t5319: expand test data multi-pack-index: load into memory midx: write header information to lockfile multi-pack-index: add 'write' verb ...
2018-08-20Merge branch 'jk/for-each-object-iteration'Libravatar Junio C Hamano1-17/+0
The API to iterate over all objects learned to optionally list objects in the order they appear in packfiles, which helps locality of access if the caller accesses these objects while as objects are enumerated. * jk/for-each-object-iteration: for_each_*_object: move declarations to object-store.h cat-file: use a single strbuf for all output cat-file: split batch "buf" into two variables cat-file: use oidset check-and-insert cat-file: support "unordered" output for --batch-all-objects cat-file: rename batch_{loose,packed}_object callbacks t1006: test cat-file --batch-all-objects with duplicates for_each_packed_object: support iterating in pack-order for_each_*_object: give more comprehensive docstrings for_each_*_object: take flag arguments as enum for_each_*_object: store flag definitions in a single location
2018-08-14for_each_*_object: move declarations to object-store.hLibravatar Jeff King1-20/+0
The for_each_loose_object() and for_each_packed_object() functions are meant to be part of a unified interface: they use the same set of for_each_object_flags, and it's not inconceivable that we might one day add a single for_each_object() wrapper around them. Let's put them together in a single file, so we can avoid awkwardness like saying "the flags for this function are over in cache.h". Moving the loose functions to packfile.h is silly. Moving the packed functions to cache.h works, but makes the "cache.h is a kitchen sink" problem worse. The best place is the recently-created object-store.h, since these are quite obviously related to object storage. The for_each_*_in_objdir() functions do not use the same flags, but they are logically part of the same interface as for_each_loose_object(), and share callback signatures. So we'll move those, as well, as they also make sense in object-store.h. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13for_each_packed_object: support iterating in pack-orderLibravatar Jeff King1-3/+5
We currently iterate over objects within a pack in .idx order, which uses the object hashes. That means that it is effectively random with respect to the location of the object within the pack. If you're going to access the actual object data, there are two reasons to move linearly through the pack itself: 1. It improves the locality of access in the packfile. In the cold-cache case, this may mean fewer disk seeks, or better usage of disk cache. 2. We store related deltas together in the packfile. Which means that the delta base cache can operate much more efficiently if we visit all of those related deltas in sequence, as the earlier items are likely to still be in the cache. Whereas if we visit the objects in random order, our cache entries are much more likely to have been evicted by unrelated deltas in the meantime. So in general, if you're going to access the object contents pack order is generally going to end up more efficient. But if you're simply generating a list of object names, or if you're going to end up sorting the result anyway, you're better off just using the .idx order, as finding the pack order means generating the in-memory pack-revindex. According to the numbers in 8b8dfd5132 (pack-revindex: radix-sort the revindex, 2013-07-11), that takes about 200ms for linux.git, and 20ms for git.git (those numbers are a few years old but are still a good ballpark). That makes it a good optimization for some cases (we can save tens of seconds in git.git by having good locality of delta access, for a 20ms cost), but a bad one for others (e.g., right now "cat-file --batch-all-objects --batch-check="%(objectname)" is 170ms in git.git, so adding 20ms to that is noticeable). Hence this patch makes it an optional flag. You can't actually do any interesting timings yet, as it's not plumbed through to any user-facing tools like cat-file. That will come in a later patch. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13for_each_*_object: give more comprehensive docstringsLibravatar Jeff King1-4/+8
We already mention the local/alternate behavior of these functions, but we can help clarify a few other behaviors: - there's no need to mention LOCAL_ONLY specifically, since we already reference the flags by type (and as we add more flags, we don't want to have to mention each) - clarify that reachability doesn't matter here; this is all accessible objects - what ordering/uniqueness guarantees we give - how pack-specific flags are handled for the loose case Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13for_each_*_object: take flag arguments as enumLibravatar Jeff King1-2/+3
It's not wrong to pass our flags in an "unsigned", as we know it will be at least as large as the enum. However, using the enum in the declaration makes it more obvious where to find the list of flags. While we're here, let's also drop the "extern" noise-words from the declarations, per our modern coding style. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13for_each_*_object: store flag definitions in a single locationLibravatar Jeff King1-6/+2
These flags were split between cache.h and packfile.h, because some of the flags apply only to packs. However, they share a single numeric namespace, since both are respected for the packed variant. Let's make sure they're defined together so that nobody accidentally adds a new flag in one location that duplicates the other. While we're here, let's also put them in an enum (which helps debugger visibility) and use "(1<<n)" rather than counting powers of 2 manually. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-26packfile: ensure that enum object_type is definedLibravatar Beat Bolli1-1/+1
When compiling under Apple LLVM version 9.1.0 (clang-902.0.39.2) with "make DEVELOPER=1 DEVOPTS=pedantic", the compiler says error: redeclaration of already-defined enum 'object_type' is a GNU extension [-Werror,-Wgnu-redeclared-enum] According to https://en.cppreference.com/w/c/language/declarations (section "Redeclaration"), a repeated declaration after the definition is only legal for structs and unions, but not for enums. Drop the belated declaration of enum object_type and include cache.h instead to make sure the enum is defined. Helped-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Beat Bolli <dev+git@drbeat.li> Reviewed-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20midx: use midx in abbreviation calculationsLibravatar Derrick Stolee1-0/+1
Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20midx: sort and deduplicate objects from packfilesLibravatar Derrick Stolee1-0/+2
Before writing a list of objects and their offsets to a multi-pack-index, we need to collect the list of objects contained in the packfiles. There may be multiple copies of some objects, so this list must be deduplicated. It is possible to artificially get into a state where there are many duplicate copies of objects. That can create high memory pressure if we are to create a list of all objects before de-duplication. To reduce this memory pressure without a significant performance drop, automatically group objects by the first byte of their object id. Use the IDX fanout tables to group the data, copy to a local array, then sort. Copy only the de-duplicated entries. Select the duplicate based on the most-recent modified time of a packfile containing the object. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20packfile: generalize pack directory listLibravatar Derrick Stolee1-0/+6
In anticipation of sharing the pack directory listing with the multi-pack-index, generalize prepare_packed_git_one() into for_each_file_in_pack_dir(). Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-18Merge branch 'sb/object-store-grafts'Libravatar Junio C Hamano1-0/+5
The conversion to pass "the_repository" and then "a_repository" throughout the object access API continues. * sb/object-store-grafts: commit: allow lookup_commit_graft to handle arbitrary repositories commit: allow prepare_commit_graft to handle arbitrary repositories shallow: migrate shallow information into the object parser path.c: migrate global git_path_* to take a repository argument cache: convert get_graft_file to handle arbitrary repositories commit: convert read_graft_file to handle arbitrary repositories commit: convert register_commit_graft to handle arbitrary repositories commit: convert commit_graft_pos() to handle arbitrary repositories shallow: add repository argument to is_repository_shallow shallow: add repository argument to check_shallow_file_for_update shallow: add repository argument to register_shallow shallow: add repository argument to set_alternate_shallow_file commit: add repository argument to lookup_commit_graft commit: add repository argument to prepare_commit_graft commit: add repository argument to read_graft_file commit: add repository argument to register_commit_graft commit: add repository argument to commit_graft_pos object: move grafts to object parser object-store: move object access functions to object-store.h
2018-05-30Merge branch 'bc/object-id'Libravatar Junio C Hamano1-2/+2
Conversion from uchar[20] to struct object_id continues. * bc/object-id: (42 commits) merge-one-file: compute empty blob object ID add--interactive: compute the empty tree value Update shell scripts to compute empty tree object ID sha1_file: only expose empty object constants through git_hash_algo dir: use the_hash_algo for empty blob object ID sequencer: use the_hash_algo for empty tree object ID cache-tree: use is_empty_tree_oid sha1_file: convert cached object code to struct object_id builtin/reset: convert use of EMPTY_TREE_SHA1_BIN builtin/receive-pack: convert one use of EMPTY_TREE_SHA1_HEX wt-status: convert two uses of EMPTY_TREE_SHA1_HEX submodule: convert several uses of EMPTY_TREE_SHA1_HEX sequencer: convert one use of EMPTY_TREE_SHA1_HEX merge: convert empty tree constant to the_hash_algo builtin/merge: switch tree functions to use object_id builtin/am: convert uses of EMPTY_TREE_SHA1_BIN to the_hash_algo sha1-file: add functions for hex empty tree and blob OIDs builtin/receive-pack: avoid hard-coded constants for push certs diff: specify abbreviation size in terms of the_hash_algo upload-pack: replace use of several hard-coded constants ...
2018-05-23Merge branch 'sb/oid-object-info'Libravatar Junio C Hamano1-2/+4
The codepath around object-info API has been taught to take the repository object (which in turn tells the API which object store the objects are to be located). * sb/oid-object-info: cache.h: allow oid_object_info to handle arbitrary repositories packfile: add repository argument to cache_or_unpack_entry packfile: add repository argument to unpack_entry packfile: add repository argument to read_object packfile: add repository argument to packed_object_info packfile: add repository argument to packed_to_object_type packfile: add repository argument to retry_bad_packed_offset cache.h: add repository argument to oid_object_info cache.h: add repository argument to oid_object_info_extended
2018-05-16object-store: move object access functions to object-store.hLibravatar Stefan Beller1-0/+5
This should make these functions easier to find and cache.h less overwhelming to read. In particular, this moves: - read_object_file - oid_object_info - write_object_file As a result, most of the codebase needs to #include object-store.h. In this patch the #include is only added to files that would fail to compile otherwise. It would be better to #include wherever identifiers from the header are used. That can happen later when we have better tooling for it. Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-05-08Merge branch 'ds/commit-graph'Libravatar Junio C Hamano1-0/+2
Precompute and store information necessary for ancestry traversal in a separate file to optimize graph walking. * ds/commit-graph: commit-graph: implement "--append" option commit-graph: build graph from starting commits commit-graph: read only from specific pack-indexes commit: integrate commit graph with commit parsing commit-graph: close under reachability commit-graph: add core.commitGraph setting commit-graph: implement git commit-graph read commit-graph: implement git-commit-graph write commit-graph: implement write_commit_graph() commit-graph: create git-commit-graph builtin graph: add commit graph design document commit-graph: add format document csum-file: refactor finalize_hashfile() method csum-file: rename hashclose() to finalize_hashfile()
2018-05-02packfile: convert find_pack_entry to object_idLibravatar brian m. carlson1-1/+1
Convert find_pack_entry and the static function fill_pack_entry to take pointers to struct object_id. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-05-02packfile: convert has_sha1_pack to object_idLibravatar brian m. carlson1-1/+1
Convert this function to take a pointer to struct object_id and rename it has_object_pack for consistency with has_object_file. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-26cache.h: allow oid_object_info to handle arbitrary repositoriesLibravatar Stefan Beller1-4/+4
This involves also adapting oid_object_info_extended and a some internal functions that are used to implement these. It all has to happen in one patch, because of a single recursive chain of calls visits all these functions. oid_object_info_extended is also used in partial clones, which allow fetching missing objects. As this series will not add the repository struct to the transport code and fetch_object(), add a TODO note and omit fetching if a user tries to use a partial clone in a repository other than the_repository. Among the functions modified to handle arbitrary repositories, unpack_entry() is one of them. Note that it still references the globals "delta_base_cache" and "delta_base_cached", but those are safe to be referenced (the former is indexed partly by "struct packed_git *", which is repo-specific, and the latter is only used to limit the size of the former as an optimization). Helped-by: Brandon Williams <bmwill@google.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Stefan Beller <sbeller@google.com> Reviewed-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-26packfile: add repository argument to unpack_entryLibravatar Stefan Beller1-1/+2
Add a repository argument to allow the callers of unpack_entry to be more specific about which repository to act on. This is a small mechanical change; it doesn't change the implementation to handle repositories other than the_repository yet. As with the previous commits, use a macro to catch callers passing a repository other than the_repository at compile time. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Stefan Beller <sbeller@google.com> Reviewed-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-26packfile: add repository argument to packed_object_infoLibravatar Jonathan Nieder1-1/+2
Add a repository argument to allow callers of packed_object_info to be more specific about which repository to handle. This is a small mechanical change; it doesn't change the implementation to handle repositories other than the_repository yet. As with the previous commits, use a macro to catch callers passing a repository other than the_repository at compile time. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Stefan Beller <sbeller@google.com> Reviewed-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-11Merge branch 'sb/packfiles-in-repository'Libravatar Junio C Hamano1-4/+7
Refactoring of the internal global data structure continues. * sb/packfiles-in-repository: packfile: keep prepare_packed_git() private packfile: allow find_pack_entry to handle arbitrary repositories packfile: add repository argument to find_pack_entry packfile: allow reprepare_packed_git to handle arbitrary repositories packfile: allow prepare_packed_git to handle arbitrary repositories packfile: allow prepare_packed_git_one to handle arbitrary repositories packfile: add repository argument to reprepare_packed_git packfile: add repository argument to prepare_packed_git packfile: add repository argument to prepare_packed_git_one packfile: allow install_packed_git to handle arbitrary repositories packfile: allow rearrange_packed_git to handle arbitrary repositories packfile: allow prepare_packed_git_mru to handle arbitrary repositories
2018-04-11Merge branch 'sb/object-store'Libravatar Junio C Hamano1-1/+4
Refactoring the internal global data structure to make it possible to open multiple repositories, work with and then close them. Rerolled by Duy on top of a separate preliminary clean-up topic. The resulting structure of the topics looked very sensible. * sb/object-store: (27 commits) sha1_file: allow sha1_loose_object_info to handle arbitrary repositories sha1_file: allow map_sha1_file to handle arbitrary repositories sha1_file: allow map_sha1_file_1 to handle arbitrary repositories sha1_file: allow open_sha1_file to handle arbitrary repositories sha1_file: allow stat_sha1_file to handle arbitrary repositories sha1_file: allow sha1_file_name to handle arbitrary repositories sha1_file: add repository argument to sha1_loose_object_info sha1_file: add repository argument to map_sha1_file sha1_file: add repository argument to map_sha1_file_1 sha1_file: add repository argument to open_sha1_file sha1_file: add repository argument to stat_sha1_file sha1_file: add repository argument to sha1_file_name sha1_file: allow prepare_alt_odb to handle arbitrary repositories sha1_file: allow link_alt_odb_entries to handle arbitrary repositories sha1_file: add repository argument to prepare_alt_odb sha1_file: add repository argument to link_alt_odb_entries sha1_file: add repository argument to read_info_alternates sha1_file: add repository argument to link_alt_odb_entry sha1_file: add raw_object_store argument to alt_odb_usable pack: move approximate object count to object store ...
2018-04-11commit-graph: read only from specific pack-indexesLibravatar Derrick Stolee1-0/+2
Teach git-commit-graph to inspect the objects only in a certain list of pack-indexes within the given pack directory. This allows updating the commit graph iteratively. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-03-26packfile: keep prepare_packed_git() privateLibravatar Nguyễn Thái Ngọc Duy1-1/+0
The reason callers have to call this is to make sure either packed_git or packed_git_mru pointers are initialized since we don't do that by default. Sometimes it's hard to see this connection between where the function is called and where packed_git pointer is used (sometimes in separate functions). Keep this dependency internal because now all access to packed_git and packed_git_mru must go through get_xxx() wrappers. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-03-26packfile: allow find_pack_entry to handle arbitrary repositoriesLibravatar Stefan Beller1-2/+1
Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-03-26packfile: add repository argument to find_pack_entryLibravatar Stefan Beller1-1/+6
While at it move the documentation to the header and mention which pack files are searched. Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>