Acknowledgements:
-----------------
- [Artem Vorotnikov](https://github.com/vorot93) for support [Rust wrapper](https://github.com/vorot93/mdbx-rs).
- [Andrew Ashikhmin](https://github.com/yperbasis) for contributing to C++ API.
Fixes:
------
- Fixed possibility of looping update GC during transaction commit (no public issue since the problem was discovered inside [Positive Technologies](https://www.ptsecurity.ru).
- Fixed `#pragma pack` to avoid provoking some compilers to generate code with [unaligned access](https://github.com/erthink/libmdbx/issues/235).
- Fixed `noexcept` for potentially throwing `txn::put()` of C++ API.
Minors:
-------
- Added stochastic test script for checking small transactions cases.
- Removed extra transaction commit/restart inside test framework.
- In debugging builds fixed a too small (single page) by default DB shrink threshold.
Acknowledgements:
-----------------
- [Francisco Vallarino](https://github.com/fjvallarino) for [Haskell bindings for libmdbx](https://hackage.haskell.org/package/libmdbx).
- [Alex Sharov](https://github.com/AskAlexSharov) for reporting and testing.
- [Andrea Lanfranchi](https://github.com/AndreaLanfranchi) for contributing.
Extensions and improvements:
----------------------------
- Added `cursor::erase()` overloads for `key` and for `key-value`.
- Resolve minor Coverity Scan issues (no fixes but some hint/comment were added).
- Resolve minor UndefinedBehaviorSanitizer issues (no fixes but some workaround were added).
Fixes:
------
- Always setup `madvise` while opening DB (fixes https://github.com/erthink/libmdbx/issues/231).
- Fixed checking legacy `P_DIRTY` flag (`0x10`) for nested/sub-pages.
Minors:
-------
- Fixed getting revision number from middle of history during amalgamation (GNU Makefile).
- Fixed search GCC tools for LTO (CMake scripts).
- Fixed/reorder dirs list for search CLANG tools for LTO (CMake scripts).
- Fixed/workarounds for CLANG < 9.x
- Fixed CMake warning about compatibility with 3.8.2
Acknowledgements:
-----------------
- [Alex Sharov](https://github.com/AskAlexSharov) for reporting and testing.
- [Andrea Lanfranchi](https://github.com/AndreaLanfranchi) for reporting bugs.
- [Lionel Debroux](https://github.com/debrouxl) for fuzzing tests and reporting bugs.
- [Sergey Fedotov](https://github.com/SergeyFromHell/) for [`node-mdbx` NodeJS bindings](https://www.npmjs.com/package/node-mdbx).
- [Kris Zyp](https://github.com/kriszyp) for [`lmdbx-store` NodeJS bindings](https://github.com/kriszyp/lmdbx-store).
- [Noel Kuntze](https://github.com/Thermi) for [draft Python bindings](https://github.com/erthink/libmdbx/commits/python-bindings).
New features, extensions and improvements:
------------------------------------------
- [Allow to predefine/override `MDBX_BUILD_TIMESTAMP` for builds reproducibility](https://github.com/erthink/libmdbx/issues/201).
- Added options support for `long-stochastic` script.
- Avoided `MDBX_TXN_FULL` error for large transactions when possible.
- The `MDBX_READERS_LIMIT` increased to `32767`.
- Raise `MDBX_TOO_LARGE` under Valgrind/ASAN if being opened DB is 100 larger than RAM (to avoid hangs and OOM).
- Minimized the size of poisoned/unpoisoned regions to avoid Valgrind/ASAN stuck.
- Added more workarounds for QEMU for testing builds for 32-bit platforms, Alpha and Sparc architectures.
- `mdbx_chk` now skips iteration & checking of DB' records if corresponding page-tree is corrupted (to avoid `SIGSEGV`, ASAN failures, etc).
- Added more checks for [rare/fuzzing corruption cases](https://github.com/erthink/libmdbx/issues/217).
Backward compatibility break:
-----------------------------
- Use file `VERSION.txt` for version information instead of `VERSION` to avoid collision with `#include <version>`.
- Rename `slice::from/to_FOO_bytes()` to `slice::envisage_from/to_FOO_length()'.
- Rename `MDBX_TEST_EXTRA` make's variable to `MDBX_SMOKE_EXTRA`.
- Some details of the C++ API have been changed for subsequent freezing.
Fixes:
------
- Fixed excess meta-pages checks in case `mdbx_chk` is called to check the DB for a specific meta page and thus could prevent switching to the selected meta page, even if the check passed without errors.
- Fixed [recursive use of SRW-lock on Windows cause by `MDBX_NOTLS` option](https://github.com/erthink/libmdbx/issues/203).
- Fixed [log a warning during a new DB creation](https://github.com/erthink/libmdbx/issues/205).
- Fixed [false-negative `mdbx_cursor_eof()` result](https://github.com/erthink/libmdbx/issues/207).
- Fixed [`make install` with non-GNU `install` utility (OSX, BSD)](https://github.com/erthink/libmdbx/issues/208).
- Fixed [installation by `CMake` in special cases by complete use `GNUInstallDirs`'s variables](https://github.com/erthink/libmdbx/issues/209).
- Fixed [C++ Buffer issue with `std::string` and alignment](https://github.com/erthink/libmdbx/issues/191).
- Fixed `safe64_reset()` for platforms without atomic 64-bit compare-and-swap.
- Fixed hang/shutdown on big-endian platforms without `__cxa_thread_atexit()`.
- Fixed [using bad meta-pages if DB was partially/recoverable corrupted](https://github.com/erthink/libmdbx/issues/217).
- Fixed extra `noexcept` for `buffer::&assign_reference()`.
- Fixed `bootid` generation on Windows for case of change system' time.
- Fixed [test framework keygen-related issue](https://github.com/erthink/libmdbx/issues/127).
