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2026-08-24reftable/stack: rename reftable_stack_new_addition()Karthik Nayak1-1/+1
Rename the function `reftable_stack_new_addition()` to `reftable_stack_addition_new()` to be more inline with our naming scheme. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-08-24reftable/stack: remove `REFTABLE_STACK_NEW_ADDITION_RELOAD`Karthik Nayak1-14/+3
In 80e7342ea8 (reftable/stack: allow locking of outdated stacks, 2024-09-24), the `REFTABLE_STACK_NEW_ADDITION_RELOAD` was introduced so that callers of `reftable_stack_init_addition()` can also reload the stack if there was a concurrent update made before the lock was obtained. Then 16684b6fae (refs/reftable: always reload stacks when creating lock, 2025-08-12) updated all of the remaining call-sites to propagate this flag to ensure that we always reload the stack whenever there was a concurrent update. As all calls to `reftable_stack_init_addition()` inevitably propagate the flag, it is safe to remove the flag and its associated code and make the reloading of the stack the default flow. This makes it easier to follow the flow and simplifies the logic. The only exceptions are: 1. Unit tests, where we explicitly do not propagate the flag. These tests are now modified with the new status quo. 2. `reftable_stack_clean()`, which was propagating 0 to `reftable_stack_new_addition()` but was then manually reloading the stack after. Here the new flow will achieve the same, while also allowing us to remove the manual reload. This also makes two checks for 'REFTABLE_OUTDATED_ERROR' redundant, so remove them also. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-07-10reftable: fix quadratic behavior in the presence of tombstonesKristofer Karlsson1-0/+2
When many tombstones are present in a reftable, operations that need to look up or iterate over refs exhibit quadratic behavior. With 8000 refs deleted and re-created, update-ref takes ~15s, quadrupling for each doubling of input size. The root cause is the merged iterator's suppress_deletions flag. When set, merged_iter_next_void() silently consumes tombstone records in a tight internal loop before returning to the caller. This prevents higher-level code from checking iteration bounds (such as prefix or refname comparisons) until after all tombstones have been scanned. This affects any code path that seeks into a range containing tombstones, including: - refs_verify_refnames_available() seeks to "refs/tags/foo-1/" to check for D/F conflicts and must scan through all subsequent tombstones before the caller can see that they are past the prefix of interest. - reftable_backend_read_ref() seeks to a specific refname and must scan through all subsequent tombstones before returning "not found", because the merged iterator skips the matching tombstone and searches for the next live record. Fix this by making suppress_deletions configurable via reftable_stack_options instead of unconditionally enabling it. Git no longer sets the flag, so tombstones are now returned to callers in the reftable backend, which skip them after their existing bounds checks. This allows iteration to terminate as soon as a tombstone past the relevant bound is encountered. Downstream users of the reftable library (e.g. libgit2) can still enable suppress_deletions through the stack options to retain the previous behavior. This also requires adding deletion checks to the log iteration paths, since suppress_deletions applied to both ref and log iterators. Both tests in p1401 go from ~13s to ~0.2s with this change. Reported-by: Jeff King <peff@peff.net> Signed-off-by: Kristofer Karlsson <krka@spotify.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-06-26reftable: split up write optionsPatrick Steinhardt1-3/+27
When initializing the reftable stack the caller may optionally pass some write options. These write options mix up two different concerns though: - Of course, they allow the caller to configure how new reftables are being written. - But they also allow the caller to configure the stack itself, like its hash ID and the `on_reload` callback. This is somewhat awkward, as it doesn't easily give the caller the flexibility to for example write multiple reftables with different options. Furthermore, this requires us to eagerly parse relevant configuration when initializing the reftable backend. Refactor the code by splitting out those options that configure the stack itself. Creating a new stack will thus only require this limited set of options, whereas the caller is expected to pass write options to all functions that end up writing tables. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-04-02reftable: introduce "reftable-system.h" headerPatrick Steinhardt1-0/+1
We're including a couple of standard headers like <stdint.h> in a bunch of locations, which makes it hard for a project to plug in their own logic for making required functionality available. For us this is for example via "compat/posix.h", which already includes all of the system headers relevant to us. Introduce a new "reftable-system.h" header that allows projects to provide their own headers. This new header is supposed to contain all the project-specific bits to provide the POSIX-like environment, and some additional supporting code. With this change, we thus have the following split in our system-specific code: - "reftable/reftable-system.h" is the project-specific header that provides a POSIX-like environment. Every project is expected to provide their own implementation. - "reftable/system.h" contains the project-independent definition of the interfaces that a project needs to implement. This file should not be touched by a project. - "reftable/system.c" contains the project-specific implementation of the interfaces defined in "system.h". Again, every project is expected to provide their own implementation. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-11-10reftable/stack: add function to check if optimization is requiredKarthik Nayak1-0/+11
The reftable backend performs auto-compaction as part of its regular flow, which is required to keep the number of tables part of a stack at bay. This allows it to stay optimized. Compaction can also be triggered voluntarily by the user via the 'git pack-refs' or the 'git refs optimize' command. However, currently there is no way for the user to check if optimization is required without actually performing it. Extract out the heuristics logic from 'reftable_stack_auto_compact()' into an internal function 'update_segment_if_compaction_required()'. Then use this to add and expose `reftable_stack_compaction_required()` which will allow users to check if the reftable backend can be optimized. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Acked-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-12reftable/stack: allow passing flags to `reftable_stack_add()`Patrick Steinhardt1-3/+6
The `reftable_stack_add()` function is a simple wrapper to lock the stack, add records to it via a callback and then commit the result. One problem with it though is that it doesn't accept any flags for creating the addition. This makes it impossible to automatically reload the stack in case it was modified before we managed to lock the stack. Add a `flags` field to plug this gap and pass it through accordingly. For now this new flag won't be used by us, but it will be used by libgit2. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
2024-11-26reftable/stack: add accessor for the hash IDPatrick Steinhardt1-0/+3
Add an accessor function that allows callers to access the hash ID of a reftable stack. This function will be used in a subsequent commit. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-10-10Merge branch 'ps/reftable-alloc-failures'Junio C Hamano1-4/+4
The reftable library is now prepared to expect that the memory allocation function given to it may fail to allocate and to deal with such an error. * ps/reftable-alloc-failures: (26 commits) reftable/basics: fix segfault when growing `names` array fails reftable/basics: ban standard allocator functions reftable: introduce `REFTABLE_FREE_AND_NULL()` reftable: fix calls to free(3P) reftable: handle trivial allocation failures reftable/tree: handle allocation failures reftable/pq: handle allocation failures when adding entries reftable/block: handle allocation failures reftable/blocksource: handle allocation failures reftable/iter: handle allocation failures when creating indexed table iter reftable/stack: handle allocation failures in auto compaction reftable/stack: handle allocation failures in `stack_compact_range()` reftable/stack: handle allocation failures in `reftable_new_stack()` reftable/stack: handle allocation failures on reload reftable/reader: handle allocation failures in `reader_init_iter()` reftable/reader: handle allocation failures for unindexed reader reftable/merged: handle allocation failures in `merged_table_init_iter()` reftable/writer: handle allocation failures in `reftable_new_writer()` reftable/writer: handle allocation failures in `writer_index_hash()` reftable/record: handle allocation failures when decoding records ...
2024-10-02reftable/merged: handle allocation failures in `merged_table_init_iter()`Patrick Steinhardt1-4/+4
Handle allocation failures in `merged_table_init_iter()`. While at it, merge `merged_iter_init()` into the function. It only has a single caller and merging them makes it easier to handle allocation failures consistently. This change also requires us to adapt `reftable_stack_init_*_iterator()` to bubble up the new error codes of `merged_table_iter_init()`. Adapt callsites accordingly. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-09-24reftable/stack: allow locking of outdated stacksPatrick Steinhardt1-2/+11
In `reftable_stack_new_addition()` we first lock the stack and then check whether it is still up-to-date. If it is not we return an error to the caller indicating that the stack is outdated. This is overly restrictive in our ref transaction interface though: we lock the stack right before we start to verify the transaction, so we do not really care whether it is outdated or not. What we really want is that the stack is up-to-date after it has been locked so that we can verify queued updates against its current state while we know that it is locked for concurrent modification. Introduce a new flag `REFTABLE_STACK_NEW_ADDITION_RELOAD` that alters the behaviour of `reftable_stack_init_addition()` in this case: when we notice that it is out-of-date we reload it instead of returning an error to the caller. This logic will be wired up in the reftable backend in the next commit. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-08-22t/helper: inline `reftable_stack_print_directory()`Patrick Steinhardt1-3/+0
Move `reftable_stack_print_directory()` into the "dump-reftable" helper. This follows the same reasoning as the preceding commit. Note that this requires us to remove the tests for this functionality in `reftable/stack_test.c`. The test does not really add much anyway, because all it verifies is that we do not crash or run into an error, and it specifically doesn't check the outputted data. Also, as the code is now part of the test helper, it doesn't make much sense to have a unit test for it in the first place. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-30Merge branch 'ps/reftable-reusable-iterator'Junio C Hamano1-0/+18
Code clean-up to make the reftable iterator closer to be reusable. * ps/reftable-reusable-iterator: reftable/merged: adapt interface to allow reuse of iterators reftable/stack: provide convenience functions to create iterators reftable/reader: adapt interface to allow reuse of iterators reftable/generic: adapt interface to allow reuse of iterators reftable/generic: move seeking of records into the iterator reftable/merged: simplify indices for subiterators reftable/merged: split up initialization and seeking of records reftable/reader: set up the reader when initializing table iterator reftable/reader: inline `reader_seek_internal()` reftable/reader: separate concerns of table iter and reftable reader reftable/reader: unify indexed and linear seeking reftable/reader: avoid copying index iterator reftable/block: use `size_t` to track restart point index
2024-05-13reftable/stack: provide convenience functions to create iteratorsPatrick Steinhardt1-0/+18
There exist a bunch of call sites in the reftable backend that want to create iterators for a reftable stack. This is rather convoluted right now, where you always have to go via the merged table. And it is about to become even more convoluted when we split up iterator initialization and seeking in the next commit. Introduce convenience functions that allow the caller to create an iterator from a reftable stack directly without going through the merged table. Adapt callers accordingly. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-13reftable: pass opts as constant pointerPatrick Steinhardt1-1/+1
We sometimes pass the refatble write options as value and sometimes as a pointer. This is quite confusing and makes the reader wonder whether the options get modified sometimes. In fact, `reftable_new_writer()` does cause the caller-provided options to get updated when some values aren't set up. This is quite unexpected, but didn't cause any harm until now. Adapt the code so that we do not modify the caller-provided values anymore. While at it, refactor the code to code to consistently pass the options as a constant pointer to clarify that the caller-provided opts will not ever get modified. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-13reftable: consistently refer to `reftable_write_options` as `opts`Patrick Steinhardt1-1/+1
Throughout the reftable library the `reftable_write_options` are sometimes referred to as `cfg` and sometimes as `opts`. Unify these to consistently use `opts` to avoid confusion. While at it, touch up the coding style a bit by removing unneeded braces around one-line statements and newlines between variable declarations. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-08reftable: implement stack, a mutable database of reftable files.Han-Wen Nienhuys1-0/+128
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>