The planned frontward release with new superior features on the day of 20 anniversary of [Positive Technologies](https://ptsecurty.com).
New:
----
- The `Big Foot` feature which significantly reduces GC overhead for processing large lists of retired pages from huge transactions.
Now _libmdbx_ avoid creating large chunks of PNLs (page number lists) which required a long sequences of free pages, aka large/overflow pages.
Thus avoiding searching, allocating and storing such sequences inside GC.
- Improved hot/online validation and checking of database pages both for more robustness and performance.
- New solid and fast method to latch meta-pages called `Troika`.
The minimum of memory barriers, reads, comparisons and conditional transitions are used.
- New `MDBX_VALIDATION` environment options to extra validation of DB structure and pages content for carefully/safe handling damaged or untrusted DB.
- Accelerated ×16/×8/×4 by AVX512/AVX2/SSE2/Neon implementations of search page sequences.
- Added the `gcrtime_seconds16dot16` counter to the "Page Operation Statistics" that accumulates time spent for GC searching and reclaiming.
- Copy-with-compactification now clears/zeroes unused gaps inside database pages.
- The `C` and `C++` APIs has been extended and/or refined to simplify using `wchar_t` pathnames.
On Windows the `mdbx_env_openW()`, `mdbx_env_get_pathW()`, `mdbx_env_copyW()`, `mdbx_env_open_for_recoveryW()` are available for now,
but the `mdbx_env_get_path()` has been replaced in favor of `mdbx_env_get_pathW()`.
- Added explicit error message for Buildroot's Microblaze toolchain maintainers.
- Added `MDBX_MANAGE_BUILD_FLAGS` build options for CMake.
- Speed-up internal `bsearch`/`lower_bound` implementation using branchless tactic, including workaround for CLANG x86 optimiser bug.
- A lot internal refinement and micro-optimisations.
- Internally counted volume of dirty pages (unused for now but for coming features).
Fixes:
------
- Never use modern `__cxa_thread_atexit()` on Apple's OSes.
- Don't check owner for finished transactions.
- Fixed typo in `MDBX_EINVAL` which breaks MingGW builds with CLANG.
37 files changed, 7604 insertions(+), 7417 deletions(-)
Signed-off-by: Леонид Юрьев (Leonid Yuriev) <leo@yuriev.ru>
The stable bugfix release.
It is planned that this will be the last release of the v0.11 branch.
New:
----
- The C++ API has been refined to simplify support for `wchar_t` in path names.
- Added explicit error message for Buildroot's Microblaze toolchain maintainers.
Fixes:
------
- Never use modern `__cxa_thread_atexit()` on Apple's OSes.
- Use `MultiByteToWideChar(CP_THREAD_ACP)` instead of `mbstowcs()`.
- Don't check owner for finished transactions.
- Fixed typo in `MDBX_EINVAL` which breaks MingGW builds with CLANG.
Minors:
-------
- Fixed variable name typo.
- Using `ldd` to check used dso.
- Added `MDBX_WEAK_IMPORT_ATTRIBUTE` macro.
- Use current transaction geometry for untouched parameters when `env_set_geometry()` called within a write transaction.
- Minor clarified `iov_page()` failure case.
14 files changed, 263 insertions(+), 252 deletions(-)
Signed-off-by: Леонид Юрьев (Leonid Yuriev) <leo@yuriev.ru>
Устранение крайне маловероятного регресса после перехода на мета-тройку:
- процесс А открыает БД и читает мета-траницы для формирования тройки;
- процесс Б постоянно коммитит новые транзакции;
- есть шанс что процесс А при чтении разных мета страниц попадет на момент их обновления более одного раза,
это может привести к ложной ошибке коллизии мета-страниц,
так как для обновляемых мета-страниц будет виден нулевой номер транзакции.
