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2025-04-07reftable: fix formatting of the license headerPatrick Steinhardt1-6/+6
The license headers used across the reftable library doesn't follow our typical coding style for multi-line comments. Fix it. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-18reftable/record: don't `BUG()` in `reftable_record_cmp()`Patrick Steinhardt1-1/+1
The reftable library aborts with a bug in case `reftable_record_cmp()` is invoked with two records of differing types. This would cause the program to die without the caller being able to handle the error, which is not something we want in the context of library code. And it ties us to the Git codebase. Refactor the code such that `reftable_record_cmp()` returns an error code separate from the actual comparison result. This requires us to also adapt some callers up the callchain in a similar fashion. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-10-02reftable/pq: handle allocation failures when adding entriesPatrick Steinhardt1-1/+1
Handle allocation failures when adding entries to the pqueue. Adapt its only caller accordingly. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-08-01t-reftable-pq: make merged_iter_pqueue_check() staticChandra Pratap1-1/+0
merged_iter_pqueue_check() is a function previously defined in reftable/pq_test.c (now t/unit-tests/t-reftable-pq.c) and used in the testing of a priority queue as defined by reftable/pq.{c, h}. As such, this function is only called by reftable/pq_test.c and it makes little sense to expose it to non-testing code via reftable/pq.h. Hence, make this function static and remove its prototype from reftable/pq.h. Mentored-by: Patrick Steinhardt <ps@pks.im> Mentored-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Chandra Pratap <chandrapratap3519@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-03-04reftable: allow inlining of a few functionsPatrick Steinhardt1-2/+10
We have a few functions which are basically just accessors to structures. As those functions are executed inside the hot loop when iterating through many refs, the fact that they cannot be inlined is costing us some performance. Move the function definitions into their respective headers so that they can be inlined. This results in a performance improvement when iterating over 1 million refs: Benchmark 1: show-ref: single matching ref (revision = HEAD~) Time (mean ± σ): 105.9 ms ± 3.6 ms [User: 103.0 ms, System: 2.8 ms] Range (min … max): 103.1 ms … 133.4 ms 1000 runs Benchmark 2: show-ref: single matching ref (revision = HEAD) Time (mean ± σ): 100.7 ms ± 3.4 ms [User: 97.8 ms, System: 2.8 ms] Range (min … max): 97.8 ms … 124.0 ms 1000 runs Summary show-ref: single matching ref (revision = HEAD) ran 1.05 ± 0.05 times faster than show-ref: single matching ref (revision = HEAD~) Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-03-04reftable/merged: make subiters own their recordsPatrick Steinhardt1-1/+1
For each subiterator, the merged table needs to track their current record. This record is owned by the priority queue though instead of by the merged iterator. This is not optimal performance-wise. For one, we need to move around records whenever we add or remove a record from the priority queue. Thus, the bigger the entries the more bytes we need to copy around. And compared to pointers, a reftable record is rather on the bigger side. The other issue is that this makes it harder to reuse the records. Refactor the code so that the merged iterator tracks ownership of the records per-subiter. Instead of having records in the priority queue, we can now use mere pointers to the per-subiter records. This also allows us to swap records between the caller and the per-subiter record instead of doing an actual copy via `reftable_record_copy_from()`, which removes the need to release the caller-provided record. This results in a noticeable speedup when iterating through many refs. The following benchmark iterates through 1 million refs: Benchmark 1: show-ref: single matching ref (revision = HEAD~) Time (mean ± σ): 145.5 ms ± 4.5 ms [User: 142.5 ms, System: 2.8 ms] Range (min … max): 141.3 ms … 177.0 ms 1000 runs Benchmark 2: show-ref: single matching ref (revision = HEAD) Time (mean ± σ): 139.0 ms ± 4.7 ms [User: 136.1 ms, System: 2.8 ms] Range (min … max): 134.2 ms … 182.2 ms 1000 runs Summary show-ref: single matching ref (revision = HEAD) ran 1.05 ± 0.05 times faster than show-ref: single matching ref (revision = HEAD~) This refactoring also allows a subsequent refactoring where we start reusing memory allocated by the reftable records because we do not need to release the caller-provided record anymore. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-03-04reftable/pq: use `size_t` to track iterator indexPatrick Steinhardt1-1/+1
The reftable priority queue is used by the merged iterator to yield records from its sub-iterators in the expected order. Each entry has a record corresponding to such a sub-iterator as well as an index that indicates which sub-iterator the record belongs to. But while the sub-iterators are tracked with a `size_t`, we store the index as an `int` in the entry. Fix this and use `size_t` consistently. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-09-15reftable: use a pointer for pq_entry paramElijah Conners1-1/+1
The speed of the merged_iter_pqueue_add() can be improved by using a pointer to the pq_entry struct, which is 96 bytes. Since the pq_entry param is worked directly on the stack and does not currently have a pointer to it, the merged_iter_pqueue_add() function is slightly slower. References to pq_entry in reftable have typically included pointers, such as both of the params for pq_less(). Since we are working with pointers in the pq_entry param, as keenly pointed out, the pq_entry param has also been made into a const since the contents of the pq_entry param are copied and not manipulated. Signed-off-by: Elijah Conners <business@elijahpepe.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-08reftable: add a heap-based priority queue for reftable recordsHan-Wen Nienhuys1-0/+33
This is needed to create a merged view multiple reftables Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>