Match multi-pack-index feature from upstream #24
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Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
The multi-pack-index feature generalizes the existing pack-index feature by indexing objects across multiple pack-files. Describe the basic file format, using a 12-byte header followed by a lookup table for a list of "chunks" which will be described later. The file ends with a footer containing a checksum using the hash algorithm. The header allows later versions to create breaking changes by advancing the version number. We can also change the hash algorithm using a different version value. We will add the individual chunk format information as we introduce the code that writes that information. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
This new 'git multi-pack-index' builtin will be the plumbing access for writing, reading, and checking multi-pack-index files. The initial implementation is a no-op. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
In anticipation of writing multi-pack-indexes, add a skeleton 'git multi-pack-index write' subcommand and send the options to a write_midx_file() method. Also create a skeleton test script that tests the 'write' subcommand. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we begin writing the multi-pack-index format to disk, start with the basics: the 12-byte header and the 20-byte checksum footer. Start with these basics so we can add the rest of the format in small increments. As we implement the format, we will use a technique to check that our computed offsets within the multi-pack-index file match what we are actually writing. Each method that writes to the hashfile will return the number of bytes written, and we will track that those values match our expectations. Currently, write_midx_header() returns 12, but is not checked. We will check the return value in a later commit. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Create a new multi_pack_index struct for loading multi-pack-indexes into memory. Create a test-tool builtin for reading basic information about that multi-pack-index to verify the correct data is written. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we build the multi-pack-index file format, we want to test the format on real repositories. Add tests that create repository data including multiple packfiles with both version 1 and version 2 formats. The current 'git multi-pack-index write' command will always write the same file with no "real" data. This will be expanded in future commits, along with the test expectations. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
When constructing a multi-pack-index file for a given object directory, read the files within the enclosed pack directory and find matches that end with ".idx" and find the correct paired packfile using add_packed_git(). Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
The multi-pack-index needs to track which packfiles it indexes. Store these in our first required chunk. Since filenames are not well structured, add padding to keep good alignment in later chunks. Modify the 'git multi-pack-index read' subcommand to output the existence of the pack-file name chunk. Modify t5319-multi-pack-index.sh to reflect this new output and the new expected number of chunks. Defense in depth: A pattern we are using in the multi-pack-index feature is to verify the data as we write it. We want to ensure we never write invalid data to the multi-pack-index. There are many checks that verify that the values we are writing fit the format definitions. This mainly helps developers while working on the feature, but it can also identify issues that only appear when dealing with very large data sets. These large sets are hard to encode into test cases. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
The final pair of chunks for the multi-pack-index file stores the object offsets. We default to using 32-bit offsets as in the pack-index version 1 format, but if there exists an offset larger than 32-bits, we use a trick similar to the pack-index version 2 format by storing all offsets at least 2^31 in a 64-bit table; we use the 32-bit table to point into that 64-bit table as necessary. We only store these 64-bit offsets if necessary, so create a test that manipulates a version 2 pack-index to fake a large offset. This allows us to test that the large offset table is created, but the data does not match the actual packfile offsets. The multi-pack-index offset does match the (corrupted) pack-index offset, so a future feature will compare these offsets during a 'verify' step. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
The core.multiPackIndex config setting controls the multi-pack- index (MIDX) feature. If false, the setting will disable all reads from the multi-pack-index file. Read this config setting in the new prepare_multi_pack_index_one() which is called during prepare_packed_git(). This check is run once per repository. Add comparison commands in t5319-multi-pack-index.sh to check typical Git behavior remains the same as the config setting is turned on and off. This currently includes 'git rev-list' and 'git log' commands to trigger several object database reads. Currently, these would only catch an error in the prepare_multi_pack_index_one(), but with later commits will catch errors in object lookups, abbreviations, and approximate object counts. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Due to how Windows handles replacing a lockfile when there is an open handle, create the close_midx() method to close the existing midx before writing the new one. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
The multi-pack-index, when present, tracks the existence of objects and their offsets within a list of packfiles. This allows us to use the multi-pack-index for object lookups, abbreviations, and object counts. When the multi-pack-index tracks a packfile, then we do not need to add that packfile to the packed_git linked list or the MRU list. We still need to load the packfiles that are not tracked by the multi-pack-index. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
If a 'git repack' command replaces existing packfiles, then we must clear the existing multi-pack-index before moving the packfiles it references. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* 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 ...
The multi-pack-index builtin has a very simple command-line interface. Instead of simply reporting usage, give the user a hint to why the arguments failed. Reported-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
A pack-file is 'local' if it is stored within the usual object directory. If it is stored in an alternate, it is non-local. Pack-files are stored using a 'pack_local' member in the packed_git struct. Add a similar 'local' member to the multi_pack_index struct and 'local' parameters to the methods that load and prepare multi- pack-indexes. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
When an object fails to decompress from a pack-file, we mark the object as 'bad' so we can retry with a different copy of the object (if such a copy exists). Before now, the multi-pack-index did not update the bad objects list for the pack-files it contains, and we did not check the bad objects list when reading an object. Now, do both. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
When prepare_packed_git is called with the report_garbage method initialized, we report unexpected files in the objects directory as garbage. Stop reporting the multi-pack-index and the pack-files it covers as garbage. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
The logic for constructing the linked list of multi-pack-indexes in the object store is incorrect. If the local object store has a multi-pack-index, but an alternate does not, then the list is dropped. Add tests that would have revealed this bug. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
dscho
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This includes commits that fixup!-revert all the midx-related commits from our GVFS branch and replaces them with the exact commits that are being merged upstream. This should automatically remove the commits during our next version rebase-and-merge action. Changes upstream: - The builtin is called 'git multi-pack-index'. - The command-line takes a 'write' verb and an '--object-dir' parameter. - We no longer have a 'midx-head' or '*.midx' files. - Instead, we have a 'multi-pack-index' file in the pack-dir. - It no longer makes sense to specify '--update-head'
dscho
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This includes commits that fixup!-revert all the midx-related commits from our GVFS branch and replaces them with the exact commits that are being merged upstream. This should automatically remove the commits during our next version rebase-and-merge action. Changes upstream: - The builtin is called 'git multi-pack-index'. - The command-line takes a 'write' verb and an '--object-dir' parameter. - We no longer have a 'midx-head' or '*.midx' files. - Instead, we have a 'multi-pack-index' file in the pack-dir. - It no longer makes sense to specify '--update-head'
dscho
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This includes commits that fixup!-revert all the midx-related commits from our GVFS branch and replaces them with the exact commits that are being merged upstream. This should automatically remove the commits during our next version rebase-and-merge action. Changes upstream: - The builtin is called 'git multi-pack-index'. - The command-line takes a 'write' verb and an '--object-dir' parameter. - We no longer have a 'midx-head' or '*.midx' files. - Instead, we have a 'multi-pack-index' file in the pack-dir. - It no longer makes sense to specify '--update-head'
dscho
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This includes commits that fixup!-revert all the midx-related commits from our GVFS branch and replaces them with the exact commits that are being merged upstream. This should automatically remove the commits during our next version rebase-and-merge action. Changes upstream: - The builtin is called 'git multi-pack-index'. - The command-line takes a 'write' verb and an '--object-dir' parameter. - We no longer have a 'midx-head' or '*.midx' files. - Instead, we have a 'multi-pack-index' file in the pack-dir. - It no longer makes sense to specify '--update-head'
dscho
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This includes commits that fixup!-revert all the midx-related commits from our GVFS branch and replaces them with the exact commits that are being merged upstream. This should automatically remove the commits during our next version rebase-and-merge action. Changes upstream: - The builtin is called 'git multi-pack-index'. - The command-line takes a 'write' verb and an '--object-dir' parameter. - We no longer have a 'midx-head' or '*.midx' files. - Instead, we have a 'multi-pack-index' file in the pack-dir. - It no longer makes sense to specify '--update-head'
derrickstolee
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This includes commits that fixup!-revert all the midx-related commits from our GVFS branch and replaces them with the exact commits that are being merged upstream. This should automatically remove the commits during our next version rebase-and-merge action. Changes upstream: - The builtin is called 'git multi-pack-index'. - The command-line takes a 'write' verb and an '--object-dir' parameter. - We no longer have a 'midx-head' or '*.midx' files. - Instead, we have a 'multi-pack-index' file in the pack-dir. - It no longer makes sense to specify '--update-head'
derrickstolee
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This includes commits that fixup!-revert all the midx-related commits from our GVFS branch and replaces them with the exact commits that are being merged upstream. This should automatically remove the commits during our next version rebase-and-merge action. Changes upstream: - The builtin is called 'git multi-pack-index'. - The command-line takes a 'write' verb and an '--object-dir' parameter. - We no longer have a 'midx-head' or '*.midx' files. - Instead, we have a 'multi-pack-index' file in the pack-dir. - It no longer makes sense to specify '--update-head'
derrickstolee
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This includes commits that fixup!-revert all the midx-related commits from our GVFS branch and replaces them with the exact commits that are being merged upstream. This should automatically remove the commits during our next version rebase-and-merge action. Changes upstream: - The builtin is called 'git multi-pack-index'. - The command-line takes a 'write' verb and an '--object-dir' parameter. - We no longer have a 'midx-head' or '*.midx' files. - Instead, we have a 'multi-pack-index' file in the pack-dir. - It no longer makes sense to specify '--update-head'
derrickstolee
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This includes commits that fixup!-revert all the midx-related commits from our GVFS branch and replaces them with the exact commits that are being merged upstream. This should automatically remove the commits during our next version rebase-and-merge action. Changes upstream: - The builtin is called 'git multi-pack-index'. - The command-line takes a 'write' verb and an '--object-dir' parameter. - We no longer have a 'midx-head' or '*.midx' files. - Instead, we have a 'multi-pack-index' file in the pack-dir. - It no longer makes sense to specify '--update-head'
derrickstolee
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This includes commits that fixup!-revert all the midx-related commits from our GVFS branch and replaces them with the exact commits that are being merged upstream. This should automatically remove the commits during our next version rebase-and-merge action. Changes upstream: - The builtin is called 'git multi-pack-index'. - The command-line takes a 'write' verb and an '--object-dir' parameter. - We no longer have a 'midx-head' or '*.midx' files. - Instead, we have a 'multi-pack-index' file in the pack-dir. - It no longer makes sense to specify '--update-head'
derrickstolee
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This includes commits that fixup!-revert all the midx-related commits from our GVFS branch and replaces them with the exact commits that are being merged upstream. This should automatically remove the commits during our next version rebase-and-merge action. Changes upstream: - The builtin is called 'git multi-pack-index'. - The command-line takes a 'write' verb and an '--object-dir' parameter. - We no longer have a 'midx-head' or '*.midx' files. - Instead, we have a 'multi-pack-index' file in the pack-dir. - It no longer makes sense to specify '--update-head'
dscho
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This includes commits that fixup!-revert all the midx-related commits from our GVFS branch and replaces them with the exact commits that are being merged upstream. This should automatically remove the commits during our next version rebase-and-merge action. Changes upstream: - The builtin is called 'git multi-pack-index'. - The command-line takes a 'write' verb and an '--object-dir' parameter. - We no longer have a 'midx-head' or '*.midx' files. - Instead, we have a 'multi-pack-index' file in the pack-dir. - It no longer makes sense to specify '--update-head'
dscho
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This includes commits that fixup!-revert all the midx-related commits from our GVFS branch and replaces them with the exact commits that are being merged upstream. This should automatically remove the commits during our next version rebase-and-merge action. Changes upstream: - The builtin is called 'git multi-pack-index'. - The command-line takes a 'write' verb and an '--object-dir' parameter. - We no longer have a 'midx-head' or '*.midx' files. - Instead, we have a 'multi-pack-index' file in the pack-dir. - It no longer makes sense to specify '--update-head'
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This includes commits that fixup!-revert all the midx-related commits from our GVFS branch and replaces them with the exact commits that are being merged upstream. This should automatically remove the commits during our next version rebase-and-merge action.
Changes upstream: