mdbx: выпуск 0.12.8 "Владимир Уткин"

Стабилизирующий выпуск с исправлением обнаруженных ошибок и устранением недочетов, в день 100-летия со дня рождения выдающегося советского и российского ученого и конструктора [Влади́мира Фёдоровича У́ткина](https://ru.wikipedia.org/wiki/Уткин,_Владимир_Фёдорович). Исправления и доработки: ------------------------ - Устранение регресса/ошибки в пути обработки `put(MDBX_MULTIPLE)` при пакетном/оптовом помещении в БД множественных значений одного ключа (aka multi-value или dupsort). Проявление проблемы зависит от компилятора и опций оптимизации/кодогенерации, но с большой вероятностью возвращется ошибка `MDBX_BAD_VALSIZE` (`-30781`), а в отладочных сборках срабатывает проверка `cASSERT(mc, !"Invalid key-size")`. Сценарии приводящие к другим проявлениям на данный момент не известны. - Реализована перезапись в `mdbx_put(MDBX_CURRENT)` всех текущих мульти-значений ключа при отсутствии флага `MDBX_NOOVERWRITE`. Ранее в такой ситуации возвращалась ошибка `MDBX_EMULTIVAL`. В текущем понимании новое поведение более удобно и не создаёт проблем совместимости с ранее написанным кодом. - Добавлена возможность использовать `mdbx_cursor_get(MDBX_GET_MULTIPLE)` без предварительной установки курсора, совмещая операцию пакетного получения данных с позиционированием курсора на передаваемый ключ. - Микрооптимизация и рефакторинг `cursor_put_nochecklen()` в продолжение исправления регресса/ошибки в пути обработки `put(MDBX_MULTIPLE)`. - Уточнение формулировок в описании API, в том числе пояснений о `SIGSEGV` и недопустимости прямого изменения данных. Более подробная информация в [ChangeLog](https://libmdbx.dqdkfa.ru/md__change_log.html). git diff' stat: 24 commits, 18 files changed, 624 insertions(+), 94 deletions(-) Signed-off-by: Леонид Юрьев (Leonid Yuriev) <leo@yuriev.ru>
mdbx: обновление ChangeLog.
2025-12-15 04:32:21 +08:00 · 2023-10-17 18:16:29 +03:00 · 2023-10-14 14:37:08 +03:00 · 2023-10-14 14:36:14 +03:00 · 2023-10-14 14:16:49 +03:00 · 2023-10-11 11:14:28 +03:00
21 changed files with 840 additions and 144 deletions
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -512,23 +512,25 @@ else()
  mark_as_advanced(MDBX_USE_OFDLOCKS)
  set(MDBX_AVOID_MSYNC_DEFAULT OFF)
 endif()
-option(MDBX_AVOID_MSYNC "Controls dirty pages tracking, spilling and persisting in MDBX_WRITEMAP mode" ${MDBX_AVOID_MSYNC_DEFAULT})
+add_mdbx_option(MDBX_AVOID_MSYNC "Controls dirty pages tracking, spilling and persisting in MDBX_WRITEMAP mode" ${MDBX_AVOID_MSYNC_DEFAULT})
 add_mdbx_option(MDBX_LOCKING "Locking method (Windows=-1, SysV=5, POSIX=1988, POSIX=2001, POSIX=2008, Futexes=1995)" AUTO)
 mark_as_advanced(MDBX_LOCKING)
 add_mdbx_option(MDBX_TRUST_RTC "Does a system have battery-backed Real-Time Clock or just a fake" AUTO)
 mark_as_advanced(MDBX_TRUST_RTC)
-option(MDBX_FORCE_ASSERTIONS "Force enable assertion checking" OFF)
-option(MDBX_DISABLE_VALIDATION "Disable some checks to reduce an overhead and detection probability of database corruption to a values closer to the LMDB" OFF)
-option(MDBX_ENABLE_REFUND "Zerocost auto-compactification during write-transactions" ON)
-option(MDBX_ENABLE_MADVISE "Using POSIX' madvise() and/or similar hints" ON)
+add_mdbx_option(MDBX_FORCE_ASSERTIONS "Force enable assertion checking" OFF)
+add_mdbx_option(MDBX_DISABLE_VALIDATION "Disable some checks to reduce an overhead and detection probability of database corruption to a values closer to the LMDB" OFF)
+mark_as_advanced(MDBX_DISABLE_VALIDATION)
+add_mdbx_option(MDBX_ENABLE_REFUND "Zerocost auto-compactification during write-transactions" ON)
+add_mdbx_option(MDBX_ENABLE_MADVISE "Using POSIX' madvise() and/or similar hints" ON)
 if (CMAKE_TARGET_BITNESS GREATER 32)
  set(MDBX_BIGFOOT_DEFAULT ON)
 else()
  set(MDBX_BIGFOOT_DEFAULT OFF)
 endif()
-option(MDBX_ENABLE_BIGFOOT "Chunking long list of retired pages during huge transactions commit to avoid use sequences of pages" ${MDBX_BIGFOOT_DEFAULT})
-option(MDBX_ENABLE_PGOP_STAT "Gathering statistics for page operations" ON)
-option(MDBX_ENABLE_PROFGC "Profiling of GC search and updates" OFF)
+add_mdbx_option(MDBX_ENABLE_BIGFOOT "Chunking long list of retired pages during huge transactions commit to avoid use sequences of pages" ${MDBX_BIGFOOT_DEFAULT})
+add_mdbx_option(MDBX_ENABLE_PGOP_STAT "Gathering statistics for page operations" ON)
+add_mdbx_option(MDBX_ENABLE_PROFGC "Profiling of GC search and updates" OFF)
+mark_as_advanced(MDBX_ENABLE_PROFGC)

 if(NOT MDBX_AMALGAMATED_SOURCE)
  if(CMAKE_CONFIGURATION_TYPES OR CMAKE_BUILD_TYPE_UPPERCASE STREQUAL "DEBUG")
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,10 +1,152 @@
 ChangeLog
---------
+=========

 English version [by Google](https://gitflic-ru.translate.goog/project/erthink/libmdbx/blob?file=ChangeLog.md&_x_tr_sl=ru&_x_tr_tl=en)
 and [by Yandex](https://translated.turbopages.org/proxy_u/ru-en.en/https/gitflic.ru/project/erthink/libmdbx/blob?file=ChangeLog.md).


+## v0.12.8 "Владимир Уткин" от 2023-10-17
+
+Стабилизирующий выпуск с исправлением обнаруженных ошибок и устранением недочетов,
+в день 100-летия со дня рождения выдающегося советского и российского ученого и конструктора [Влади́мира Фёдоровича У́ткина](https://ru.wikipedia.org/wiki/Уткин,_Владимир_Фёдорович).
+
+```
+git diff' stat: 24 commits, 18 files changed, 624 insertions(+), 94 deletions(-)
+Signed-off-by: Леонид Юрьев (Leonid Yuriev) <leo@yuriev.ru>
+```
+
+Благодарности:
+
+ - [Alain Picard](https://github.com/castortech) за сообщение о проблеме
+   с обработкой `MDBX_MULTIPLE` и помощь в тестировании.
+
+Исправления и доработки:
+
+ - Устранение регресса/ошибки в пути обработки `put(MDBX_MULTIPLE)` при пакетном/оптовом
+   помещении в БД множественных значений одного ключа (aka multi-value или dupsort).
+   Проявление проблемы зависит от компилятора и опций оптимизации/кодогенерации, но с большой вероятностью возвращется
+   ошибка `MDBX_BAD_VALSIZE` (`-30781`), а в отладочных сборках срабатывает проверка `cASSERT(mc, !"Invalid key-size")`.
+   Сценарии приводящие к другим проявлениям на данный момент не известны.
+
+ - Реализована перезапись в `mdbx_put(MDBX_CURRENT)` всех текущих мульти-значений ключа
+   при отсутствии флага `MDBX_NOOVERWRITE`. Ранее в такой ситуации возвращалась ошибка `MDBX_EMULTIVAL`.
+   В текущем понимании новое поведение более удобно и не создаёт проблем совместимости с ранее написанным кодом.
+
+ - Добавлена возможность использовать `mdbx_cursor_get(MDBX_GET_MULTIPLE)` без предварительной установки
+   курсора, совмещая операцию пакетного получения данных с позиционированием курсора на передаваемый ключ.
+
+ - Микрооптимизация и рефакторинг `cursor_put_nochecklen()` в продолжение исправления
+   регресса/ошибки в пути обработки `put(MDBX_MULTIPLE)`.
+
+ - Уточнение формулировок в описании API, в том числе пояснений о `SIGSEGV`
+   и недопустимости прямого изменения данных.
+
+Мелочи:
+
+ - Исправление несущественных предупреждений при `MDBX_ENABLE_PROFGC=ON`.
+ - Добавление `slice::as_pod<typename>()` в C++ API.
+ - Добавление перегрузки `txn::put_multiple()` и контроля POD в C++ API.
+ - Добавление smoke-теста для `put(MDBX_MULTIPLE)`.
+ - Добавление дополнительных smoke-тестов в область видимости ctest.
+ - Устранение жалоб Valgrind на инвариантное чтение неинициализированной памяти
+   и утечки памяти в одном из тестов.
+ - Костыль для глушения/игнорирования `EDEADLK` в ряде сценариев при
+   использовании Valgrind или ASAN. В частности, это устраняет
+   ложно-негативный результат проверки БД посредством `mdbx_chk -wc`,
+   т.е. проверку БД в кооперативном (не эксклюзивном) режиме чтения-записи
+   в сборках с поддержкой Valgrind или включеным ASAN. Для более подробной
+   информации см. [соответствующий коммит](https://gitflic.ru/project/erthink/libmdbx/commit/1aead6869a7eff1a85e400ab3eeecb4c8b904fe6).
+ - Доработка `mdbx_dump_val()` используемой для логирования и отладки.
+ - Устранение предупреждений Valgrind при логировании в отладочных сборках.
+ - Доработка использования `filesystem` для старых компиляторов.
+ - Сокращение излишнего вызова `osal_thread_self()`.
+ - Вывод информации о большинстве mdbx-опций при сборке посредством CMake.
+ - Добавление определений макросов для Doxygen.
+
+
+--------------------------------------------------------------------------------
+
+
+## v0.12.7 "Артек" от 2023-06-16
+
+Стабилизирующий выпуск с исправлением обнаруженных ошибок и устранением
+недочетов, в день основания международного детского центра [«Арте́к»](https://ru.wikipedia.org/wiki/Артек).
+
+```
+14 files changed, 222 insertions(+), 56 deletions(-)
+Signed-off-by: Леонид Юрьев (Leonid Yuriev) <leo@yuriev.ru>
+```
+
+Исправления и доработки:
+
+  - Исправление опечатки в имени переменной внутри `mdbx_env_turn_for_recovery()`,
+    что приводило к неверному поведению в некоторых ситуациях.
+
+    С точки зрения пользователя, с учетом актуальных сценариев использования
+    утилиты `mdbx_chk`, был только один специфический/редкий сценарий
+    проявления ошибки/проблемы - когда выполнялась проверка и активация
+    слабой/weak мета-страницы с НЕ-последней транзакцией после системной
+    аварии машины, где БД использовалась в хрупком/небезопасном режиме.
+    В сценарии, при успешной проверке целевой страницы и её последующей
+    активации выводилось сообщение об ошибке, связанной со срабатыванием
+    механизма контроля не-когерентности кэша файловой системы и отображенных
+    в ОЗУ данных БД. При этом БД успешно восстанавливалось и не было
+    каких-либо негативных последствия, кроме самого сообщения об ошибке.
+
+    Технически же ошибка проявлялась при "переключении" на мета-страницу,
+    когда у хотя-бы одной из двух других мета-страниц номер транзакции был
+    больше:
+
+      * Если содержимое других мета-страниц было корректным, а номера
+        связанных транзакций были больше, то результирующий номер транзакции в
+        целевой/активируемой мета-страницы устанавливается без учета этих
+        мета-страниц и мог быть меньше-или-равным.
+
+      * В результате, если такие мета-страницы были в статусе слабых/weak, то
+        при закрытии БД после переключения могла срабатывать защита от
+        не-когерентности unified buffer/page cache, а в отладочных сборках могла
+        срабатывать assert-проверка.
+
+      * Если же такие мета-страницы были в статусе сильных/steady, то
+        переключение на новую мета-страницу могло не давать эффекта либо
+        приводить к появлению двух мета-страниц с одинаковым номером транзакции,
+        что является ошибочной ситуацией.
+
+  - Обходное решение проблем сборки посредством GCC с использование опций `-m32 -arch=i686 -Ofast`.
+    Проблема обусловлена ошибкой GCC, из-за которой конструкция `__attribute__((__target__("sse2")))`
+    не включает полноценное использование инструкций SSE и SSE2, если это не было сделано посредством
+    опций командной строки, но была использована опция `-Ofast`. В результате сборка заканчивалась
+    сообщением об ошибке:
+        `error: inlining failed in call to 'always_inline' '_mm_movemask_ps': target specific option mismatch`
+
+  - Доработка режима "восстановления" БД и переключения на заданную мета-страницу:
+      * Устранение обновления без необходимости мета-страницы с увеличением номера транзакции;
+      * Устранение вывода (логирования) бессмысленного/лишнего предупреждения о пропуске обновления геометрии БД;
+      * Более ожидаемое и безопасное поведение при проверке БД с указанием целевой мета-страницы в режиме чтения-записи.
+
+    Теперь при открытии БД посредством `mdbx_env_open_for_recovery()` не
+    выполняется неявное изменение/обновление БД, в том числе при закрытии
+    БД. Это позволяет обезопасить БД (снизить шанс её разрушения) если
+    пользователь при попытке восстановления, либо просто в качестве
+    эксперимента, задал утилите `mdbx_chk` неверную или опасную комбинацию
+    параметров. При этом обычная проверка, как и явное переключение
+    мета-страниц, работают по-прежнему.
+
+Мелочи:
+
+ - Незначительное уточнение CMake-пробника для `std::filesystem`,
+   проверяющего необходимость линковки с дополнительными библиотеками C++.
+ - Устранение минорных предупреждений старых компиляторов в тестах.
+ - Устранение причины ложно-позитивного предупреждения новых версий GCC в C++ API.
+ - Исправление ссылки на репозиторий бенчмарка ioarena.
+ - Добавление перекрестных ссылок в doxygen-документацию по C++ API.
+ - Уточнение ограничений в разделе [Restrictions & Caveats](https://libmdbx.dqdkfa.ru/intro.html#restrictions).
+ - Исправление ссылок на описание `mdbx_canary_put()`.
+
+
+--------------------------------------------------------------------------------
+
+
 ## v0.12.6 "ЦСКА" от 2023-04-29

 Стабилизирующий выпуск с исправлением обнаруженных ошибок и устранением
@@ -354,7 +496,7 @@ Signed-off-by: Леонид Юрьев (Leonid Yuriev) <leo@yuriev.ru>
   суммарный размер пары ключ-значение.

 - Реализовано использование асинхронной (overlapped) записи в Windows,
-   включая использования небуфферизированного ввода-вывода и `WriteGather()`.
+   включая использования небуферизированного ввода-вывода и `WriteGather()`.
   Это позволяет сократить накладные расходы и частично обойти проблемы
   Windows с низкой производительностью ввода-вывода, включая большие
   задержки `FlushFileBuffers()`. Новый код также обеспечивает консолидацию
@@ -483,7 +625,7 @@ New:
 - 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,
+   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.
--- a/README.md
+++ b/README.md
@@ -277,7 +277,7 @@ the user's point of view.
   > and up to 30% faster when _libmdbx_ compiled with specific build options
   > which downgrades several runtime checks to be match with LMDB behaviour.
   >
-   > These and other results could be easily reproduced with [ioArena](https://abf.io/erthink/ioarena.git) just by `make bench-quartet` command,
+   > These and other results could be easily reproduced with [ioArena](https://abf.io/erthink/ioarena) just by `make bench-quartet` command,
   > including comparisons with [RockDB](https://en.wikipedia.org/wiki/RocksDB)
   > and [WiredTiger](https://en.wikipedia.org/wiki/WiredTiger).

@@ -659,7 +659,7 @@ Bindings
 Performance comparison
 ======================

-All benchmarks were done in 2015 by [IOArena](https://abf.io/erthink/ioarena.git)
+All benchmarks were done in 2015 by [IOArena](https://abf.io/erthink/ioarena)
 and multiple [scripts](https://github.com/pmwkaa/ioarena/tree/HL%2B%2B2015)
 runs on Lenovo Carbon-2 laptop, i7-4600U 2.1 GHz (2 physical cores, 4 HyperThreading cores), 8 Gb RAM,
 SSD SAMSUNG MZNTD512HAGL-000L1 (DXT23L0Q) 512 Gb.
--- a/cmake/compiler.cmake
+++ b/cmake/compiler.cmake
@@ -1039,9 +1039,15 @@ macro(probe_libcxx_filesystem)
        #endif

        int main(int argc, const char*argv[]) {
-          fs::path probe(argv[0]);
+          std::string str(argv[0]);
+          fs::path probe(str);
          if (argc != 1) throw fs::filesystem_error(std::string("fake"), std::error_code());
-          return fs::is_directory(probe.relative_path());
+          int r = fs::is_directory(probe.relative_path());
+          for (auto const& i : fs::directory_iterator(probe)) {
+            ++r;
+            (void)i;
+          }
+          return r;
        }
        ]])
      set(LIBCXX_FILESYSTEM "")
--- a/docs/Doxyfile.in
+++ b/docs/Doxyfile.in
@@ -2224,14 +2224,24 @@ INCLUDE_FILE_PATTERNS  =
 # recursively expanded use the := operator instead of the = operator.
 # This tag requires that the tag ENABLE_PREPROCESSING is set to YES.

-PREDEFINED             = DOXYGEN MDBX_DECLARE_EXCEPTION \
-	MDBX_NOTHROW_PURE_FUNCTION MDBX_PURE_FUNCTION \
-	MDBX_NOTHROW_CONST_FUNCTION \
-	MDBX_CXX01_CONSTEXPR MDBX_CXX01_CONSTEXPR_VAR \
-	MDBX_CXX11_CONSTEXPR MDBX_CXX11_CONSTEXPR_VAR \
-	MDBX_CXX14_CONSTEXPR MDBX_CXX14_CONSTEXPR_VAR \
-	MDBX_CXX17_CONSTEXPR MDBX_CXX20_CONSTEXPR \
-	MDBX_CXX17_NOEXCEPT
+
+PREDEFINED             = DOXYGEN \
+	MDBX_CXX20_CONCEPT(CONCEPT,NAME)="CONCEPT NAME" \
+	MDBX_STD_FILESYSTEM_PATH=::mdbx::filesystem::path \
+	MDBX_U128_TYPE=uint128_t MDBX_I128_TYPE=int128_t \
+	MDBX_DECLARE_EXCEPTION(NAME)="struct LIBMDBX_API_TYPE NAME : public exception{NAME(const ::mdbx::error &); virtual ~NAME() noexcept; }" \
+	MDBX_PURE_FUNCTION=[[gnu::pure]] \
+	MDBX_NOTHROW_PURE_FUNCTION="[[gnu::pure, gnu::nothrow]]" \
+	MDBX_CONST_FUNCTION=[[gnu::const]] \
+	MDBX_NOTHROW_CONST_FUNCTION="[[gnu::const, gnu::nothrow]]" \
+	MDBX_CXX01_CONSTEXPR=constexpr MDBX_CXX01_CONSTEXPR_VAR=constexpr \
+	MDBX_CXX11_CONSTEXPR=constexpr MDBX_CXX11_CONSTEXPR_VAR=constexpr \
+	MDBX_CXX14_CONSTEXPR=constexpr MDBX_CXX14_CONSTEXPR_VAR=constexpr \
+	MDBX_CXX17_CONSTEXPR=constexpr MDBX_CXX20_CONSTEXPR=constexpr \
+	MDBX_CXX17_NOEXCEPT=noexcept MDBX_IF_CONSTEXPR=constexpr \
+	MDBX_CXX20_LIKELY=[[likely]] MDBX_CXX20_UNLIKELY=[[unlikely]] \
+	MDBX_MAYBE_UNUSED=[[maybe_unused]] \
+	MDBX_DEPRECATED=[[deprecated]]

 # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then this
 # tag can be used to specify a list of macro names that should be expanded. The
--- a/docs/_restrictions.md
+++ b/docs/_restrictions.md
@@ -35,10 +35,11 @@ or debugging of a client application while retaining an active read
 transaction. LMDB this results in `MDB_MAP_FULL` error and subsequent write
 performance degradation.

-MDBX mostly solve "long-lived" readers issue by using the Handle-Slow-Readers
-\ref MDBX_hsr_func callback which allows to abort long-lived read transactions,
-and using the \ref MDBX_LIFORECLAIM mode which addresses subsequent performance degradation.
-The "next" version of libmdbx (\ref MithrilDB) will completely solve this.
+MDBX mostly solve "long-lived" readers issue by using the
+Handle-Slow-Readers \ref MDBX_hsr_func callback which allows to abort
+long-lived read transactions, and using the \ref MDBX_LIFORECLAIM mode
+which addresses subsequent performance degradation. The "next" version
+of libmdbx (\ref MithrilDB) will completely solve this.

 - Avoid suspending a process with active transactions. These would then be
  "long-lived" as above.
@@ -80,6 +81,19 @@ list of pages to be retired.

 Both of these issues will be addressed in MithrilDB.

+#### Since v0.12.1 and later
+Some aspects related to GC have been refined and improved, in particular:
+
+  - The search for free consecutive/adjacent pages through GC has been
+    significantly speeded, including acceleration using
+    NOEN/SSE2/AVX2/AVX512 instructions.
+
+  - 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.
+

 ## Space reservation
 An MDBX database configuration will often reserve considerable unused
@@ -87,6 +101,10 @@ memory address space and maybe file size for future growth. This does
 not use actual memory or disk space, but users may need to understand
 the difference so they won't be scared off.

+However, on 64-bit systems with a relative small amount of RAM, such
+reservation can deplete system resources (trigger ENOMEM error, etc)
+when setting an inadequately large upper DB size using \ref
+mdbx_env_set_geometry() or \ref mdbx::env::geometry. So just avoid this.

 ## Remote filesystems
 Do not use MDBX databases on remote filesystems, even between processes
--- a/mdbx.h
+++ b/mdbx.h
@@ -1876,7 +1876,8 @@ enum MDBX_error_t {
  MDBX_BAD_RSLOT = -30783,

  /** Transaction is not valid for requested operation,
-   * e.g. had errored and be must aborted, has a child, or is invalid */
+   * e.g. had errored and be must aborted, has a child/nested transaction,
+   * or is invalid */
  MDBX_BAD_TXN = -30782,

  /** Invalid size or alignment of key or data for target database,
@@ -2699,11 +2700,12 @@ MDBX_DEPRECATED LIBMDBX_INLINE_API(int, mdbx_env_info,
 *     success. The \ref MDBX_RESULT_TRUE means no data pending for flush
 *     to disk, and 0 otherwise. Some possible errors are:
 *
- * \retval MDBX_EACCES   the environment is read-only.
- * \retval MDBX_BUSY     the environment is used by other thread
+ * \retval MDBX_EACCES   The environment is read-only.
+ * \retval MDBX_BUSY     The environment is used by other thread
 *                       and `nonblock=true`.
- * \retval MDBX_EINVAL   an invalid parameter was specified.
- * \retval MDBX_EIO      an error occurred during synchronization. */
+ * \retval MDBX_EINVAL   An invalid parameter was specified.
+ * \retval MDBX_EIO      An error occurred during the flushing/writing data
+ *                       to a storage medium/disk. */
 LIBMDBX_API int mdbx_env_sync_ex(MDBX_env *env, bool force, bool nonblock);

 /** \brief The shortcut to calling \ref mdbx_env_sync_ex() with
@@ -2846,9 +2848,9 @@ LIBMDBX_INLINE_API(int, mdbx_env_get_syncperiod,
 *
 * Only a single thread may call this function. All transactions, databases,
 * and cursors must already be closed before calling this function. Attempts
- * to use any such handles after calling this function will cause a `SIGSEGV`.
- * The environment handle will be freed and must not be used again after this
- * call.
+ * to use any such handles after calling this function is UB and would cause
+ * a `SIGSEGV`. The environment handle will be freed and must not be used again
+ * after this call.
 *
 * \param [in] env        An environment handle returned by
 *                        \ref mdbx_env_create().
@@ -2878,7 +2880,8 @@ LIBMDBX_INLINE_API(int, mdbx_env_get_syncperiod,
 *                     is expected, i.e. \ref MDBX_env instance was freed in
 *                     proper manner.
 *
- * \retval MDBX_EIO    An error occurred during synchronization. */
+ * \retval MDBX_EIO    An error occurred during the flushing/writing data
+ *                     to a storage medium/disk. */
 LIBMDBX_API int mdbx_env_close_ex(MDBX_env *env, bool dont_sync);

 /** \brief The shortcut to calling \ref mdbx_env_close_ex() with
@@ -3918,7 +3921,8 @@ LIBMDBX_API int mdbx_txn_commit_ex(MDBX_txn *txn, MDBX_commit_latency *latency);
 *                               by current thread.
 * \retval MDBX_EINVAL           Transaction handle is NULL.
 * \retval MDBX_ENOSPC           No more disk space.
- * \retval MDBX_EIO              A system-level I/O error occurred.
+ * \retval MDBX_EIO              An error occurred during the flushing/writing
+ *                               data to a storage medium/disk.
 * \retval MDBX_ENOMEM           Out of memory. */
 LIBMDBX_INLINE_API(int, mdbx_txn_commit, (MDBX_txn * txn)) {
  return mdbx_txn_commit_ex(txn, NULL);
@@ -4031,7 +4035,7 @@ LIBMDBX_API int mdbx_txn_renew(MDBX_txn *txn);
 /** \brief The fours integers markers (aka "canary") associated with the
 * environment.
 * \ingroup c_crud
- * \see mdbx_canary_set()
+ * \see mdbx_canary_put()
 * \see mdbx_canary_get()
 *
 * The `x`, `y` and `z` values could be set by \ref mdbx_canary_put(), while the
@@ -4069,10 +4073,10 @@ LIBMDBX_API int mdbx_canary_put(MDBX_txn *txn, const MDBX_canary *canary);
 /** \brief Returns fours integers markers (aka "canary") associated with the
 * environment.
 * \ingroup c_crud
- * \see mdbx_canary_set()
+ * \see mdbx_canary_put()
 *
 * \param [in] txn     A transaction handle returned by \ref mdbx_txn_begin().
- * \param [in] canary  The address of an MDBX_canary structure where the
+ * \param [in] canary  The address of an \ref MDBX_canary structure where the
 *                     information will be copied.
 *
 * \returns A non-zero error value on failure and 0 on success. */
@@ -4084,9 +4088,9 @@ LIBMDBX_API int mdbx_canary_get(const MDBX_txn *txn, MDBX_canary *canary);
 * \see mdbx_get_datacmp \see mdbx_dcmp()
 *
 * \anchor avoid_custom_comparators
- * It is recommend not using custom comparison functions, but instead
- * converting the keys to one of the forms that are suitable for built-in
- * comparators (for instance take look to the \ref value2key).
+ * \deprecated It is recommend not using custom comparison functions, but
+ * instead converting the keys to one of the forms that are suitable for
+ * built-in comparators (for instance take look to the \ref value2key).
 * The reasons to not using custom comparators are:
 *   - The order of records could not be validated without your code.
 *     So `mdbx_chk` utility will reports "wrong order" errors
@@ -4316,7 +4320,7 @@ LIBMDBX_API int mdbx_dbi_dupsort_depthmask(MDBX_txn *txn, MDBX_dbi dbi,
 enum MDBX_dbi_state_t {
  /** DB was written in this txn */
  MDBX_DBI_DIRTY = 0x01,
-  /** Named-DB record is older than txnID */
+  /** Cached Named-DB record is older than txnID */
  MDBX_DBI_STALE = 0x02,
  /** Named-DB handle opened in this txn */
  MDBX_DBI_FRESH = 0x04,
@@ -4398,9 +4402,14 @@ LIBMDBX_API int mdbx_drop(MDBX_txn *txn, MDBX_dbi dbi, bool del);
 * items requires the use of \ref mdbx_cursor_get().
 *
 * \note The memory pointed to by the returned values is owned by the
- * database. The caller need not dispose of the memory, and may not
- * modify it in any way. For values returned in a read-only transaction
- * any modification attempts will cause a `SIGSEGV`.
+ * database. The caller MUST not dispose of the memory, and MUST not modify it
+ * in any way regardless in a read-only nor read-write transactions!
+ * For case a database opened without the \ref MDBX_WRITEMAP modification
+ * attempts likely will cause a `SIGSEGV`. However, when a database opened with
+ * the \ref MDBX_WRITEMAP or in case values returned inside read-write
+ * transaction are located on a "dirty" (modified and pending to commit) pages,
+ * such modification will silently accepted and likely will lead to DB and/or
+ * data corruption.
 *
 * \note Values returned from the database are valid only until a
 * subsequent update operation, or the end of the transaction.
@@ -4650,7 +4659,7 @@ LIBMDBX_API int mdbx_replace_ex(MDBX_txn *txn, MDBX_dbi dbi,
 LIBMDBX_API int mdbx_del(MDBX_txn *txn, MDBX_dbi dbi, const MDBX_val *key,
                         const MDBX_val *data);

-/** \brief Create a cursor handle but not bind it to transaction nor DBI handle.
+/** \brief Create a cursor handle but not bind it to transaction nor DBI-handle.
 * \ingroup c_cursors
 *
 * A cursor cannot be used when its database handle is closed. Nor when its
@@ -4674,7 +4683,7 @@ LIBMDBX_API int mdbx_del(MDBX_txn *txn, MDBX_dbi dbi, const MDBX_val *key,
 * \returns Created cursor handle or NULL in case out of memory. */
 LIBMDBX_API MDBX_cursor *mdbx_cursor_create(void *context);

-/** \brief Set application information associated with the \ref MDBX_cursor.
+/** \brief Set application information associated with the cursor.
 * \ingroup c_cursors
 * \see mdbx_cursor_get_userctx()
 *
@@ -4697,11 +4706,11 @@ LIBMDBX_API int mdbx_cursor_set_userctx(MDBX_cursor *cursor, void *ctx);
 MDBX_NOTHROW_PURE_FUNCTION LIBMDBX_API void *
 mdbx_cursor_get_userctx(const MDBX_cursor *cursor);

-/** \brief Bind cursor to specified transaction and DBI handle.
+/** \brief Bind cursor to specified transaction and DBI-handle.
 * \ingroup c_cursors
 *
 * Using of the `mdbx_cursor_bind()` is equivalent to calling
- * \ref mdbx_cursor_renew() but with specifying an arbitrary dbi handle.
+ * \ref mdbx_cursor_renew() but with specifying an arbitrary DBI-handle.
 *
 * A cursor may be associated with a new transaction, and referencing a new or
 * the same database handle as it was created with. This may be done whether the
@@ -4715,7 +4724,7 @@ mdbx_cursor_get_userctx(const MDBX_cursor *cursor);
 *
 * \param [in] txn      A transaction handle returned by \ref mdbx_txn_begin().
 * \param [in] dbi      A database handle returned by \ref mdbx_dbi_open().
- * \param [out] cursor  A cursor handle returned by \ref mdbx_cursor_create().
+ * \param [in] cursor   A cursor handle returned by \ref mdbx_cursor_create().
 *
 * \returns A non-zero error value on failure and 0 on success,
 *          some possible errors are:
@@ -4774,15 +4783,14 @@ LIBMDBX_API int mdbx_cursor_open(MDBX_txn *txn, MDBX_dbi dbi,
 *                     or \ref mdbx_cursor_create(). */
 LIBMDBX_API void mdbx_cursor_close(MDBX_cursor *cursor);

-/** \brief Renew a cursor handle.
+/** \brief Renew a cursor handle for use within the given transaction.
 * \ingroup c_cursors
 *
- * The cursor may be associated with a new transaction, and referencing a new or
- * the same database handle as it was created with. This may be done whether the
- * previous transaction is live or dead.
+ * A cursor may be associated with a new transaction whether the previous
+ * transaction is running or finished.
 *
 * Using of the `mdbx_cursor_renew()` is equivalent to calling
- * \ref mdbx_cursor_bind() with the DBI handle that previously
+ * \ref mdbx_cursor_bind() with the DBI-handle that previously
 * the cursor was used with.
 *
 * \note In contrast to LMDB, the MDBX allow any cursor to be re-used by using
@@ -4796,7 +4804,9 @@ LIBMDBX_API void mdbx_cursor_close(MDBX_cursor *cursor);
 *          some possible errors are:
 * \retval MDBX_THREAD_MISMATCH  Given transaction is not owned
 *                               by current thread.
- * \retval MDBX_EINVAL  An invalid parameter was specified. */
+ * \retval MDBX_EINVAL  An invalid parameter was specified.
+ * \retval MDBX_BAD_DBI The cursor was not bound to a DBI-handle
+ *                      or such a handle became invalid. */
 LIBMDBX_API int mdbx_cursor_renew(MDBX_txn *txn, MDBX_cursor *cursor);

 /** \brief Return the cursor's transaction handle.
@@ -4834,6 +4844,16 @@ LIBMDBX_API int mdbx_cursor_copy(const MDBX_cursor *src, MDBX_cursor *dest);
 * to which data refers.
 * \see mdbx_get()
 *
+ * \note The memory pointed to by the returned values is owned by the
+ * database. The caller MUST not dispose of the memory, and MUST not modify it
+ * in any way regardless in a read-only nor read-write transactions!
+ * For case a database opened without the \ref MDBX_WRITEMAP modification
+ * attempts likely will cause a `SIGSEGV`. However, when a database opened with
+ * the \ref MDBX_WRITEMAP or in case values returned inside read-write
+ * transaction are located on a "dirty" (modified and pending to commit) pages,
+ * such modification will silently accepted and likely will lead to DB and/or
+ * data corruption.
+ *
 * \param [in] cursor    A cursor handle returned by \ref mdbx_cursor_open().
 * \param [in,out] key   The key for a retrieved item.
 * \param [in,out] data  The data of a retrieved item.
@@ -4860,6 +4880,16 @@ LIBMDBX_API int mdbx_cursor_get(MDBX_cursor *cursor, MDBX_val *key,
 * array to which `pairs` refers.
 * \see mdbx_cursor_get()
 *
+ * \note The memory pointed to by the returned values is owned by the
+ * database. The caller MUST not dispose of the memory, and MUST not modify it
+ * in any way regardless in a read-only nor read-write transactions!
+ * For case a database opened without the \ref MDBX_WRITEMAP modification
+ * attempts likely will cause a `SIGSEGV`. However, when a database opened with
+ * the \ref MDBX_WRITEMAP or in case values returned inside read-write
+ * transaction are located on a "dirty" (modified and pending to commit) pages,
+ * such modification will silently accepted and likely will lead to DB and/or
+ * data corruption.
+ *
 * \param [in] cursor     A cursor handle returned by \ref mdbx_cursor_open().
 * \param [out] count     The number of key and value item returned, on success
 *                        it always be the even because the key-value
--- a/mdbx.h++
+++ b/mdbx.h++
@@ -80,7 +80,8 @@

 #if defined(__cpp_lib_filesystem) && __cpp_lib_filesystem >= 201703L
 #include <filesystem>
-#elif __has_include(<experimental/filesystem>)
+#elif defined(__cpp_lib_string_view) && __cpp_lib_string_view >= 201606L &&    \
+    __has_include(<experimental/filesystem>)
 #include <experimental/filesystem>
 #endif

@@ -368,6 +369,7 @@ using string = ::std::basic_string<char, ::std::char_traits<char>, ALLOCATOR>;
 using filehandle = ::mdbx_filehandle_t;
 #if defined(DOXYGEN) ||                                                        \
    (defined(__cpp_lib_filesystem) && __cpp_lib_filesystem >= 201703L &&       \
+     defined(__cpp_lib_string_view) && __cpp_lib_string_view >= 201606L &&     \
     (!defined(__MAC_OS_X_VERSION_MIN_REQUIRED) ||                             \
      __MAC_OS_X_VERSION_MIN_REQUIRED >= 101500) &&                            \
     (!defined(__IPHONE_OS_VERSION_MIN_REQUIRED) ||                            \
@@ -394,6 +396,16 @@ using path = ::std::wstring;
 using path = ::std::string;
 #endif /* mdbx::path */

+#if defined(__SIZEOF_INT128__) ||                                              \
+    (defined(_INTEGRAL_MAX_BITS) && _INTEGRAL_MAX_BITS >= 128)
+#ifndef MDBX_U128_TYPE
+#define MDBX_U128_TYPE __uint128_t
+#endif /* MDBX_U128_TYPE */
+#ifndef MDBX_I128_TYPE
+#define MDBX_I128_TYPE __int128_t
+#endif /* MDBX_I128_TYPE */
+#endif /* __SIZEOF_INT128__ || _INTEGRAL_MAX_BITS >= 128 */
+
 #if __cplusplus >= 201103L || defined(DOXYGEN)
 /// \brief Duration in 1/65536 units of second.
 using duration = ::std::chrono::duration<unsigned, ::std::ratio<1, 65536>>;
@@ -552,6 +564,7 @@ MDBX_DECLARE_EXCEPTION(transaction_overlapping);
 [[noreturn]] LIBMDBX_API void throw_max_length_exceeded();
 [[noreturn]] LIBMDBX_API void throw_out_range();
 [[noreturn]] LIBMDBX_API void throw_allocators_mismatch();
+[[noreturn]] LIBMDBX_API void throw_bad_value_size();
 static MDBX_CXX14_CONSTEXPR size_t check_length(size_t bytes);
 static MDBX_CXX14_CONSTEXPR size_t check_length(size_t headroom,
                                                size_t payload);
@@ -1029,6 +1042,35 @@ struct LIBMDBX_API_TYPE slice : public ::MDBX_val {
    return slice(size_t(-1));
  }

+  template <typename POD> MDBX_CXX14_CONSTEXPR POD as_pod() const {
+    static_assert(::std::is_standard_layout<POD>::value &&
+                      !::std::is_pointer<POD>::value,
+                  "Must be a standard layout type!");
+    if (MDBX_LIKELY(size() == sizeof(POD)))
+      MDBX_CXX20_LIKELY {
+        POD r;
+        memcpy(&r, data(), sizeof(r));
+        return r;
+      }
+    throw_bad_value_size();
+  }
+
+#ifdef MDBX_U128_TYPE
+  MDBX_U128_TYPE as_uint128() const;
+#endif /* MDBX_U128_TYPE */
+  uint64_t as_uint64() const;
+  uint32_t as_uint32() const;
+  uint16_t as_uint16() const;
+  uint8_t as_uint8() const;
+
+#ifdef MDBX_I128_TYPE
+  MDBX_I128_TYPE as_int128() const;
+#endif /* MDBX_I128_TYPE */
+  int64_t as_int64() const;
+  int32_t as_int32() const;
+  int16_t as_int16() const;
+  int8_t as_int8() const;
+
 protected:
  MDBX_CXX11_CONSTEXPR slice(size_t invalid_length) noexcept
      : ::MDBX_val({nullptr, invalid_length}) {}
@@ -2292,6 +2334,10 @@ public:
    return buffer(::mdbx::slice::wrap(pod), make_reference, allocator);
  }

+  template <typename POD> MDBX_CXX14_CONSTEXPR POD as_pod() const {
+    return slice_.as_pod<POD>();
+  }
+
  /// \brief Reserves storage space.
  void reserve(size_t wanna_headroom, size_t wanna_tailroom) {
    wanna_headroom = ::std::min(::std::max(headroom(), wanna_headroom),
@@ -3000,7 +3046,11 @@ public:

  //----------------------------------------------------------------------------

-  /// Database geometry for size management.
+  /// \brief Database geometry for size management.
+  /// \see env_managed::create_parameters
+  /// \see env_managed::env_managed(const ::std::string &pathname, const
+  /// create_parameters &, const operate_parameters &, bool accede)
+
  struct LIBMDBX_API_TYPE geometry {
    enum : int64_t {
      default_value = -1,         ///< Means "keep current or use default"
@@ -3659,6 +3709,8 @@ public:
                       bool accede = true);

  /// \brief Additional parameters for creating a new database.
+  /// \see env_managed(const ::std::string &pathname, const create_parameters &,
+  /// const operate_parameters &, bool accede)
  struct create_parameters {
    env::geometry geometry;
    mdbx_mode_t file_mode_bits{0640};
@@ -3969,10 +4021,20 @@ public:
                      size_t values_count, put_mode mode,
                      bool allow_partial = false);
  template <typename VALUE>
+  size_t put_multiple(map_handle map, const slice &key,
+                      const VALUE *values_array, size_t values_count,
+                      put_mode mode, bool allow_partial = false) {
+    static_assert(::std::is_standard_layout<VALUE>::value &&
+                      !::std::is_pointer<VALUE>::value &&
+                      !::std::is_array<VALUE>::value,
+                  "Must be a standard layout type!");
+    return put_multiple(map, key, sizeof(VALUE), values_array, values_count,
+                        mode, allow_partial);
+  }
+  template <typename VALUE>
  void put_multiple(map_handle map, const slice &key,
                    const ::std::vector<VALUE> &vector, put_mode mode) {
-    put_multiple(map, key, sizeof(VALUE), vector.data(), vector.size(), mode,
-                 false);
+    put_multiple(map, key, vector.data(), vector.size(), mode);
  }

  inline ptrdiff_t estimate(map_handle map, pair from, pair to) const;
@@ -5134,7 +5196,7 @@ inline filehandle env::get_filehandle() const {
 }

 inline MDBX_env_flags_t env::get_flags() const {
-  unsigned bits;
+  unsigned bits = 0;
  error::success_or_throw(::mdbx_env_get_flags(handle_, &bits));
  return MDBX_env_flags_t(bits);
 }
--- a/src/core.c
+++ b/src/core.c
@@ -835,6 +835,9 @@ atomic_store64(MDBX_atomic_uint64_t *p, const uint64_t value,
               enum MDBX_memory_order order) {
  STATIC_ASSERT(sizeof(MDBX_atomic_uint64_t) == 8);
 #if MDBX_64BIT_ATOMIC
+#if __GNUC_PREREQ(11, 0)
+  STATIC_ASSERT(__alignof__(MDBX_atomic_uint64_t) >= sizeof(uint64_t));
+#endif /* GNU C >= 11 */
 #ifdef MDBX_HAVE_C11ATOMICS
  assert(atomic_is_lock_free(MDBX_c11a_rw(uint64_t, p)));
  atomic_store_explicit(MDBX_c11a_rw(uint64_t, p), value, mo_c11_store(order));
@@ -3631,18 +3634,15 @@ const char *mdbx_dump_val(const MDBX_val *key, char *const buf,
    char *const detent = buf + bufsize - 2;
    char *ptr = buf;
    *ptr++ = '<';
-    for (size_t i = 0; i < key->iov_len; i++) {
-      const ptrdiff_t left = detent - ptr;
-      assert(left > 0);
-      int len = snprintf(ptr, left, "%02x", data[i]);
-      if (len < 0 || len >= left)
-        break;
-      ptr += len;
-    }
-    if (ptr < detent) {
-      ptr[0] = '>';
-      ptr[1] = '\0';
+    for (size_t i = 0; i < key->iov_len && ptr < detent; i++) {
+      const char hex[16] = {'0', '1', '2', '3', '4', '5', '6', '7',
+                            '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
+      *ptr++ = hex[data[i] >> 4];
+      *ptr++ = hex[data[i] & 15];
    }
+    if (ptr < detent)
+      *ptr++ = '>';
+    *ptr = '\0';
  }
  return buf;
 }
@@ -6469,27 +6469,47 @@ MDBX_MAYBE_UNUSED static __always_inline size_t __builtin_clzl(size_t value) {
 #define MDBX_ATTRIBUTE_TARGET(target) __attribute__((__target__(target)))
 #endif /* MDBX_ATTRIBUTE_TARGET */

-#if defined(__SSE2__)
+#ifndef MDBX_GCC_FASTMATH_i686_SIMD_WORKAROUND
+/* Workaround for GCC's bug with `-m32 -march=i686 -Ofast`
+ * gcc/i686-buildroot-linux-gnu/12.2.0/include/xmmintrin.h:814:1:
+ *     error: inlining failed in call to 'always_inline' '_mm_movemask_ps':
+ *            target specific option mismatch */
+#if !defined(__FAST_MATH__) || !__FAST_MATH__ || !defined(__GNUC__) ||         \
+    defined(__e2k__) || defined(__clang__) || defined(__amd64__) ||            \
+    defined(__SSE2__)
+#define MDBX_GCC_FASTMATH_i686_SIMD_WORKAROUND 0
+#else
+#define MDBX_GCC_FASTMATH_i686_SIMD_WORKAROUND 1
+#endif
+#endif /* MDBX_GCC_FASTMATH_i686_SIMD_WORKAROUND */
+
+#if defined(__SSE2__) && defined(__SSE__)
 #define MDBX_ATTRIBUTE_TARGET_SSE2 /* nope */
 #elif (defined(_M_IX86_FP) && _M_IX86_FP >= 2) || defined(__amd64__)
 #define __SSE2__
 #define MDBX_ATTRIBUTE_TARGET_SSE2 /* nope */
-#elif defined(MDBX_ATTRIBUTE_TARGET) && defined(__ia32__)
-#define MDBX_ATTRIBUTE_TARGET_SSE2 MDBX_ATTRIBUTE_TARGET("sse2")
+#elif defined(MDBX_ATTRIBUTE_TARGET) && defined(__ia32__) &&                   \
+    !MDBX_GCC_FASTMATH_i686_SIMD_WORKAROUND
+#define MDBX_ATTRIBUTE_TARGET_SSE2 MDBX_ATTRIBUTE_TARGET("sse,sse2")
 #endif /* __SSE2__ */

 #if defined(__AVX2__)
 #define MDBX_ATTRIBUTE_TARGET_AVX2 /* nope */
-#elif defined(MDBX_ATTRIBUTE_TARGET) && defined(__ia32__)
-#define MDBX_ATTRIBUTE_TARGET_AVX2 MDBX_ATTRIBUTE_TARGET("avx2")
+#elif defined(MDBX_ATTRIBUTE_TARGET) && defined(__ia32__) &&                   \
+    !MDBX_GCC_FASTMATH_i686_SIMD_WORKAROUND
+#define MDBX_ATTRIBUTE_TARGET_AVX2 MDBX_ATTRIBUTE_TARGET("sse,sse2,avx,avx2")
 #endif /* __AVX2__ */

+#if defined(MDBX_ATTRIBUTE_TARGET_AVX2)
 #if defined(__AVX512BW__)
 #define MDBX_ATTRIBUTE_TARGET_AVX512BW /* nope */
 #elif defined(MDBX_ATTRIBUTE_TARGET) && defined(__ia32__) &&                   \
+    !MDBX_GCC_FASTMATH_i686_SIMD_WORKAROUND &&                                 \
    (__GNUC_PREREQ(6, 0) || __CLANG_PREREQ(5, 0))
-#define MDBX_ATTRIBUTE_TARGET_AVX512BW MDBX_ATTRIBUTE_TARGET("avx512bw")
+#define MDBX_ATTRIBUTE_TARGET_AVX512BW                                         \
+  MDBX_ATTRIBUTE_TARGET("sse,sse2,avx,avx2,avx512bw")
 #endif /* __AVX512BW__ */
+#endif /* MDBX_ATTRIBUTE_TARGET_AVX2 for MDBX_ATTRIBUTE_TARGET_AVX512BW */

 #ifdef MDBX_ATTRIBUTE_TARGET_SSE2
 MDBX_ATTRIBUTE_TARGET_SSE2 static __always_inline unsigned
@@ -6563,6 +6583,15 @@ diffcmp2mask_avx2(const pgno_t *const ptr, const ptrdiff_t offset,
  return _mm256_movemask_ps(*(const __m256 *)&cmp);
 }

+MDBX_ATTRIBUTE_TARGET_AVX2 static __always_inline unsigned
+diffcmp2mask_sse2avx(const pgno_t *const ptr, const ptrdiff_t offset,
+                     const __m128i pattern) {
+  const __m128i f = _mm_loadu_si128((const __m128i *)ptr);
+  const __m128i l = _mm_loadu_si128((const __m128i *)(ptr + offset));
+  const __m128i cmp = _mm_cmpeq_epi32(_mm_sub_epi32(f, l), pattern);
+  return _mm_movemask_ps(*(const __m128 *)&cmp);
+}
+
 MDBX_MAYBE_UNUSED __hot MDBX_ATTRIBUTE_TARGET_AVX2 static pgno_t *
 scan4seq_avx2(pgno_t *range, const size_t len, const size_t seq) {
  assert(seq > 0 && len > seq);
@@ -6608,7 +6637,7 @@ scan4seq_avx2(pgno_t *range, const size_t len, const size_t seq) {
  }
 #endif /* __SANITIZE_ADDRESS__ */
  if (range - 3 > detent) {
-    mask = diffcmp2mask_sse2(range - 3, offset, *(const __m128i *)&pattern);
+    mask = diffcmp2mask_sse2avx(range - 3, offset, *(const __m128i *)&pattern);
    if (mask)
      return range + 28 - __builtin_clz(mask);
    range -= 4;
@@ -6682,7 +6711,7 @@ scan4seq_avx512bw(pgno_t *range, const size_t len, const size_t seq) {
    range -= 8;
  }
  if (range - 3 > detent) {
-    mask = diffcmp2mask_sse2(range - 3, offset, *(const __m128i *)&pattern);
+    mask = diffcmp2mask_sse2avx(range - 3, offset, *(const __m128i *)&pattern);
    if (mask)
      return range + 28 - __builtin_clz(mask);
    range -= 4;
@@ -7212,7 +7241,7 @@ bailout:
 #if MDBX_ENABLE_PROFGC
  size_t majflt_after;
  prof->xtime_cpu += osal_cputime(&majflt_after) - cputime_before;
-  prof->majflt += majflt_after - majflt_before;
+  prof->majflt += (uint32_t)(majflt_after - majflt_before);
 #endif /* MDBX_ENABLE_PROFGC */
  return ret;
 }
@@ -8086,13 +8115,9 @@ retry:;
  }

  const bool inside_txn = (env->me_txn0->mt_owner == osal_thread_self());
-  meta_ptr_t head;
-  if (inside_txn | locked)
-    head = meta_recent(env, &env->me_txn0->tw.troika);
-  else {
-    const meta_troika_t troika = meta_tap(env);
-    head = meta_recent(env, &troika);
-  }
+  const meta_troika_t troika =
+      (inside_txn | locked) ? env->me_txn0->tw.troika : meta_tap(env);
+  const meta_ptr_t head = meta_recent(env, &troika);
  const uint64_t unsynced_pages =
      atomic_load64(&env->me_lck->mti_unsynced_pages, mo_Relaxed);
  if (unsynced_pages == 0) {
@@ -8105,10 +8130,19 @@ retry:;
  if (!inside_txn && locked && (env->me_flags & MDBX_WRITEMAP) &&
      unlikely(head.ptr_c->mm_geo.next >
               bytes2pgno(env, env->me_dxb_mmap.current))) {
-    rc = dxb_resize(env, head.ptr_c->mm_geo.next, head.ptr_c->mm_geo.now,
-                    head.ptr_c->mm_geo.upper, implicit_grow);
-    if (unlikely(rc != MDBX_SUCCESS))
-      goto bailout;
+
+    if (unlikely(env->me_stuck_meta >= 0) &&
+        troika.recent != (uint8_t)env->me_stuck_meta) {
+      NOTICE("skip %s since wagering meta-page (%u) is mispatch the recent "
+             "meta-page (%u)",
+             "sync datafile", env->me_stuck_meta, troika.recent);
+      rc = MDBX_RESULT_TRUE;
+    } else {
+      rc = dxb_resize(env, head.ptr_c->mm_geo.next, head.ptr_c->mm_geo.now,
+                      head.ptr_c->mm_geo.upper, implicit_grow);
+      if (unlikely(rc != MDBX_SUCCESS))
+        goto bailout;
+    }
  }

  const size_t autosync_threshold =
@@ -8187,6 +8221,14 @@ retry:;
  eASSERT(env, inside_txn || locked);
  eASSERT(env, !inside_txn || (flags & MDBX_SHRINK_ALLOWED) == 0);

+  if (!head.is_steady && unlikely(env->me_stuck_meta >= 0) &&
+      troika.recent != (uint8_t)env->me_stuck_meta) {
+    NOTICE("skip %s since wagering meta-page (%u) is mispatch the recent "
+           "meta-page (%u)",
+           "sync datafile", env->me_stuck_meta, troika.recent);
+    rc = MDBX_RESULT_TRUE;
+    goto bailout;
+  }
  if (!head.is_steady || ((flags & MDBX_SAFE_NOSYNC) == 0 && unsynced_pages)) {
    DEBUG("meta-head %" PRIaPGNO ", %s, sync_pending %" PRIu64,
          data_page(head.ptr_c)->mp_pgno, durable_caption(head.ptr_c),
@@ -9086,7 +9128,7 @@ static int txn_renew(MDBX_txn *txn, const unsigned flags) {
    }
 #if defined(MDBX_USE_VALGRIND) || defined(__SANITIZE_ADDRESS__)
    txn_valgrind(env, txn);
-#endif
+#endif /* MDBX_USE_VALGRIND || __SANITIZE_ADDRESS__ */
    txn->mt_owner = tid;
    return MDBX_SUCCESS;
  }
@@ -9154,7 +9196,7 @@ int mdbx_txn_renew(MDBX_txn *txn) {

  rc = txn_renew(txn, MDBX_TXN_RDONLY);
  if (rc == MDBX_SUCCESS) {
-    txn->mt_owner = osal_thread_self();
+    tASSERT(txn, txn->mt_owner == osal_thread_self());
    DEBUG("renew txn %" PRIaTXN "%c %p on env %p, root page %" PRIaPGNO
          "/%" PRIaPGNO,
          txn->mt_txnid, (txn->mt_flags & MDBX_TXN_RDONLY) ? 'r' : 'w',
@@ -9768,8 +9810,10 @@ static int txn_end(MDBX_txn *txn, const unsigned mode) {
                txn->mt_txnid == slot->mr_txnid.weak &&
                    slot->mr_txnid.weak >= env->me_lck->mti_oldest_reader.weak);
 #if defined(MDBX_USE_VALGRIND) || defined(__SANITIZE_ADDRESS__)
+        atomic_add32(&env->me_ignore_EDEADLK, 1);
        txn_valgrind(env, nullptr);
-#endif
+        atomic_sub32(&env->me_ignore_EDEADLK, 1);
+#endif /* MDBX_USE_VALGRIND || __SANITIZE_ADDRESS__ */
        atomic_store32(&slot->mr_snapshot_pages_used, 0, mo_Relaxed);
        safe64_reset(&slot->mr_txnid, false);
        atomic_store32(&env->me_lck->mti_readers_refresh_flag, true,
@@ -9798,7 +9842,7 @@ static int txn_end(MDBX_txn *txn, const unsigned mode) {
 #if defined(MDBX_USE_VALGRIND) || defined(__SANITIZE_ADDRESS__)
    if (txn == env->me_txn0)
      txn_valgrind(env, nullptr);
-#endif
+#endif /* MDBX_USE_VALGRIND || __SANITIZE_ADDRESS__ */

    txn->mt_flags = MDBX_TXN_FINISHED;
    txn->mt_owner = 0;
@@ -10213,6 +10257,14 @@ static int gcu_prepare_backlog(MDBX_txn *txn, gcu_context_t *ctx) {
 }

 static __inline void gcu_clean_reserved(MDBX_env *env, MDBX_val pnl) {
+#if MDBX_DEBUG && (defined(MDBX_USE_VALGRIND) || defined(__SANITIZE_ADDRESS__))
+  /* Для предотвращения предупреждения Valgrind из mdbx_dump_val()
+   * вызванное через макрос DVAL_DEBUG() на выходе
+   * из cursor_set(MDBX_SET_KEY), которая вызывается ниже внутри update_gc() в
+   * цикле очистки и цикле заполнения зарезервированных элементов. */
+  memset(pnl.iov_base, 0xBB, pnl.iov_len);
+#endif /* MDBX_DEBUG && (MDBX_USE_VALGRIND || __SANITIZE_ADDRESS__) */
+
  /* PNL is initially empty, zero out at least the length */
  memset(pnl.iov_base, 0, sizeof(pgno_t));
  if ((env->me_flags & (MDBX_WRITEMAP | MDBX_NOMEMINIT)) == 0)
@@ -10528,6 +10580,15 @@ retry:
          if (unlikely(rc != MDBX_SUCCESS))
            goto bailout;

+#if MDBX_DEBUG && (defined(MDBX_USE_VALGRIND) || defined(__SANITIZE_ADDRESS__))
+          /* Для предотвращения предупреждения Valgrind из mdbx_dump_val()
+           * вызванное через макрос DVAL_DEBUG() на выходе
+           * из cursor_set(MDBX_SET_KEY), которая вызывается как выше в цикле
+           * очистки, так и ниже в цикле заполнения зарезервированных элементов.
+           */
+          memset(data.iov_base, 0xBB, data.iov_len);
+#endif /* MDBX_DEBUG && (MDBX_USE_VALGRIND || __SANITIZE_ADDRESS__) */
+
          if (retired_pages_before == MDBX_PNL_GETSIZE(txn->tw.retired_pages)) {
            const size_t at = (ctx->lifo == MDBX_PNL_ASCENDING)
                                  ? left - chunk
@@ -10565,6 +10626,16 @@ retry:
        rc = cursor_put_nochecklen(&ctx->cursor, &key, &data, MDBX_RESERVE);
        if (unlikely(rc != MDBX_SUCCESS))
          goto bailout;
+
+#if MDBX_DEBUG && (defined(MDBX_USE_VALGRIND) || defined(__SANITIZE_ADDRESS__))
+        /* Для предотвращения предупреждения Valgrind из mdbx_dump_val()
+         * вызванное через макрос DVAL_DEBUG() на выходе
+         * из cursor_set(MDBX_SET_KEY), которая вызывается как выше в цикле
+         * очистки, так и ниже в цикле заполнения зарезервированных элементов.
+         */
+        memset(data.iov_base, 0xBB, data.iov_len);
+#endif /* MDBX_DEBUG && (MDBX_USE_VALGRIND || __SANITIZE_ADDRESS__) */
+
        /* Retry if tw.retired_pages[] grew during the Put() */
      } while (data.iov_len < MDBX_PNL_SIZEOF(txn->tw.retired_pages));

@@ -11049,7 +11120,7 @@ bailout:

  MDBX_PNL_SETSIZE(txn->tw.relist, 0);
 #if MDBX_ENABLE_PROFGC
-  env->me_lck->mti_pgop_stat.gc_prof.wloops += ctx->loop;
+  env->me_lck->mti_pgop_stat.gc_prof.wloops += (uint32_t)ctx->loop;
 #endif /* MDBX_ENABLE_PROFGC */
  TRACE("<<< %zu loops, rc = %d", ctx->loop, rc);
  return rc;
@@ -11884,6 +11955,7 @@ int mdbx_txn_commit_ex(MDBX_txn *txn, MDBX_commit_latency *latency) {
          (size_t)(commit_txnid - txn->mt_txnid));
  }
 #endif
+  meta.unsafe_sign = MDBX_DATASIGN_NONE;
  meta_set_txnid(env, &meta, commit_txnid);

  rc = sync_locked(env, env->me_flags | txn->mt_flags | MDBX_SHRINK_ALLOWED,
@@ -13732,8 +13804,9 @@ __cold static int setup_dxb(MDBX_env *env, const int lck_rc,
      mdbx_is_readahead_reasonable(used_bytes, 0) == MDBX_RESULT_TRUE;
 #endif /* MDBX_ENABLE_MADVISE */

-  err = osal_mmap(env->me_flags, &env->me_dxb_mmap, env->me_dbgeo.now,
-                  env->me_dbgeo.upper, lck_rc ? MMAP_OPTION_TRUNCATE : 0);
+  err = osal_mmap(
+      env->me_flags, &env->me_dxb_mmap, env->me_dbgeo.now, env->me_dbgeo.upper,
+      (lck_rc && env->me_stuck_meta < 0) ? MMAP_OPTION_TRUNCATE : 0);
  if (unlikely(err != MDBX_SUCCESS))
    return err;

@@ -13933,7 +14006,12 @@ __cold static int setup_dxb(MDBX_env *env, const int lck_rc,
    }

    const meta_ptr_t recent = meta_recent(env, &troika);
-    if (memcmp(&header.mm_geo, &recent.ptr_c->mm_geo, sizeof(header.mm_geo))) {
+    if (/* не учитываем различия в geo.next */
+        header.mm_geo.grow_pv != recent.ptr_c->mm_geo.grow_pv ||
+        header.mm_geo.shrink_pv != recent.ptr_c->mm_geo.shrink_pv ||
+        header.mm_geo.lower != recent.ptr_c->mm_geo.lower ||
+        header.mm_geo.upper != recent.ptr_c->mm_geo.upper ||
+        header.mm_geo.now != recent.ptr_c->mm_geo.now) {
      if ((env->me_flags & MDBX_RDONLY) != 0 ||
          /* recovery mode */ env->me_stuck_meta >= 0) {
        WARNING("skipped update meta.geo in %s mode: from l%" PRIaPGNO
@@ -14383,8 +14461,12 @@ __cold static int __must_check_result override_meta(MDBX_env *env,
  if (unlikely(MDBX_IS_ERROR(rc)))
    return MDBX_PROBLEM;

-  if (shape && memcmp(model, shape, sizeof(MDBX_meta)) == 0)
+  if (shape && memcmp(model, shape, sizeof(MDBX_meta)) == 0) {
+    NOTICE("skip overriding meta-%zu since no changes "
+           "for txnid #%" PRIaTXN,
+           target, txnid);
    return MDBX_SUCCESS;
+  }

  if (env->me_flags & MDBX_WRITEMAP) {
 #if MDBX_ENABLE_PGOP_STAT
@@ -14438,14 +14520,16 @@ __cold int mdbx_env_turn_for_recovery(MDBX_env *env, unsigned target) {
               MDBX_EXCLUSIVE))
    return MDBX_EPERM;

-  const MDBX_meta *target_meta = METAPAGE(env, target);
-  txnid_t new_txnid = safe64_txnid_next(constmeta_txnid(target_meta));
-  for (size_t n = 0; n < NUM_METAS; ++n) {
+  const MDBX_meta *const target_meta = METAPAGE(env, target);
+  txnid_t new_txnid = constmeta_txnid(target_meta);
+  if (new_txnid < MIN_TXNID)
+    new_txnid = MIN_TXNID;
+  for (unsigned n = 0; n < NUM_METAS; ++n) {
    if (n == target)
      continue;
-    MDBX_meta meta = *METAPAGE(env, target);
-    if (validate_meta(env, &meta, pgno2page(env, n), (pgno_t)n, nullptr) !=
-        MDBX_SUCCESS) {
+    MDBX_page *const page = pgno2page(env, n);
+    MDBX_meta meta = *page_meta(page);
+    if (validate_meta(env, &meta, page, n, nullptr) != MDBX_SUCCESS) {
      int err = override_meta(env, n, 0, nullptr);
      if (unlikely(err != MDBX_SUCCESS))
        return err;
@@ -15234,7 +15318,7 @@ bailout:
  } else {
 #if defined(MDBX_USE_VALGRIND) || defined(__SANITIZE_ADDRESS__)
    txn_valgrind(env, nullptr);
-#endif
+#endif /* MDBX_USE_VALGRIND || __SANITIZE_ADDRESS__ */
  }
  osal_free(env_pathname.buffer_for_free);
  return rc;
@@ -16795,11 +16879,13 @@ static __hot int cursor_get(MDBX_cursor *mc, MDBX_val *key, MDBX_val *data,
    }
    break;
  case MDBX_GET_MULTIPLE:
-    if (unlikely(data == NULL || !(mc->mc_flags & C_INITIALIZED)))
+    if (unlikely(!data))
      return MDBX_EINVAL;
-    if (unlikely(!(mc->mc_db->md_flags & MDBX_DUPFIXED)))
+    if (unlikely((mc->mc_db->md_flags & MDBX_DUPFIXED) == 0))
      return MDBX_INCOMPATIBLE;
-    rc = MDBX_SUCCESS;
+    rc = (mc->mc_flags & C_INITIALIZED)
+             ? MDBX_SUCCESS
+             : cursor_set(mc, key, data, MDBX_SET).err;
    if ((mc->mc_xcursor->mx_cursor.mc_flags & (C_INITIALIZED | C_EOF)) !=
        C_INITIALIZED)
      break;
@@ -17158,9 +17244,6 @@ static __hot int cursor_touch(MDBX_cursor *const mc, const MDBX_val *key,

 static __hot int cursor_put_nochecklen(MDBX_cursor *mc, const MDBX_val *key,
                                       MDBX_val *data, unsigned flags) {
-  MDBX_page *sub_root = nullptr;
-  MDBX_val xdata, *rdata, dkey, olddata;
-  MDBX_db nested_dupdb;
  int err;
  DKBUF_DEBUG;
  MDBX_env *const env = mc->mc_txn->mt_env;
@@ -17168,7 +17251,6 @@ static __hot int cursor_put_nochecklen(MDBX_cursor *mc, const MDBX_val *key,
        DDBI(mc), DKEY_DEBUG(key), key->iov_len,
        DVAL_DEBUG((flags & MDBX_RESERVE) ? nullptr : data), data->iov_len);

-  int dupdata_flag = 0;
  if ((flags & MDBX_CURRENT) != 0 && (mc->mc_flags & C_SUB) == 0) {
    if (unlikely(flags & (MDBX_APPEND | MDBX_NOOVERWRITE)))
      return MDBX_EINVAL;
@@ -17227,10 +17309,11 @@ static __hot int cursor_put_nochecklen(MDBX_cursor *mc, const MDBX_val *key,
    rc = MDBX_NO_ROOT;
  } else if ((flags & MDBX_CURRENT) == 0) {
    bool exact = false;
+    MDBX_val lastkey, olddata;
    if ((flags & MDBX_APPEND) && mc->mc_db->md_entries > 0) {
-      rc = cursor_last(mc, &dkey, &olddata);
+      rc = cursor_last(mc, &lastkey, &olddata);
      if (likely(rc == MDBX_SUCCESS)) {
-        const int cmp = mc->mc_dbx->md_cmp(key, &dkey);
+        const int cmp = mc->mc_dbx->md_cmp(key, &lastkey);
        if (likely(cmp > 0)) {
          mc->mc_ki[mc->mc_top]++; /* step forward for appending */
          rc = MDBX_NOTFOUND;
@@ -17295,7 +17378,7 @@ static __hot int cursor_put_nochecklen(MDBX_cursor *mc, const MDBX_val *key,
  }

  mc->mc_flags &= ~C_DEL;
-  rdata = data;
+  MDBX_val xdata, *rdata = data;
  size_t mcount = 0, dcount = 0;
  if (unlikely(flags & MDBX_MULTIPLE)) {
    dcount = data[1].iov_len;
@@ -17340,11 +17423,15 @@ static __hot int cursor_put_nochecklen(MDBX_cursor *mc, const MDBX_val *key,
    mc->mc_flags |= C_INITIALIZED;
  }

-  bool insert_key, insert_data, do_sub = false;
-  insert_key = insert_data = (rc != MDBX_SUCCESS);
+  MDBX_val dkey, olddata;
+  MDBX_db nested_dupdb;
+  MDBX_page *sub_root = nullptr;
+  bool insert_key, insert_data;
  uint16_t fp_flags = P_LEAF;
  MDBX_page *fp = env->me_pbuf;
  fp->mp_txnid = mc->mc_txn->mt_front;
+  insert_key = insert_data = (rc != MDBX_SUCCESS);
+  dkey.iov_base = nullptr;
  if (insert_key) {
    /* The key does not exist */
    DEBUG("inserting key at index %i", mc->mc_ki[mc->mc_top]);
@@ -17519,7 +17606,6 @@ static __hot int cursor_put_nochecklen(MDBX_cursor *mc, const MDBX_val *key,
          /* Back up original data item */
          memcpy(dkey.iov_base = fp + 1, olddata.iov_base,
                 dkey.iov_len = olddata.iov_len);
-          dupdata_flag = 1;

          /* Make sub-page header for the dup items, with dummy body */
          fp->mp_flags = P_LEAF | P_SUBP;
@@ -17623,11 +17709,10 @@ static __hot int cursor_put_nochecklen(MDBX_cursor *mc, const MDBX_val *key,
          }
        }

-        rdata = &xdata;
-        flags |= F_DUPDATA;
-        do_sub = true;
        if (!insert_key)
          node_del(mc, 0);
+        rdata = &xdata;
+        flags |= F_DUPDATA;
        goto new_sub;
      }

@@ -17712,8 +17797,8 @@ new_sub:;
     * storing the user data in the keys field, so there are strict
     * size limits on dupdata. The actual data fields of the child
     * DB are all zero size. */
-    if (do_sub) {
-      int xflags;
+    if (flags & F_DUPDATA) {
+      unsigned xflags;
      size_t ecount;
    put_sub:
      xdata.iov_len = 0;
@@ -17734,13 +17819,11 @@ new_sub:;
      if (sub_root)
        mc->mc_xcursor->mx_cursor.mc_pg[0] = sub_root;
      /* converted, write the original data first */
-      if (dupdata_flag) {
+      if (dkey.iov_base) {
        rc = cursor_put_nochecklen(&mc->mc_xcursor->mx_cursor, &dkey, &xdata,
                                   xflags);
        if (unlikely(rc))
          goto bad_sub;
-        /* we've done our job */
-        dkey.iov_len = 0;
      }
      if (!(node_flags(node) & F_SUBDATA) || sub_root) {
        /* Adjust other cursors pointing to mp */
@@ -17757,7 +17840,7 @@ new_sub:;
            continue;
          if (m2->mc_pg[i] == mp) {
            if (m2->mc_ki[i] == mc->mc_ki[i]) {
-              err = cursor_xinit2(m2, mx, dupdata_flag);
+              err = cursor_xinit2(m2, mx, dkey.iov_base != nullptr);
              if (unlikely(err != MDBX_SUCCESS))
                return err;
            } else if (!insert_key && m2->mc_ki[i] < nkeys) {
@@ -17801,6 +17884,7 @@ new_sub:;
        if (mcount < dcount) {
          data[0].iov_base = ptr_disp(data[0].iov_base, data[0].iov_len);
          insert_key = insert_data = false;
+          dkey.iov_base = nullptr;
          goto more;
        }
      }
@@ -21055,6 +21139,10 @@ int mdbx_put(MDBX_txn *txn, MDBX_dbi dbi, const MDBX_val *key, MDBX_val *data,
        tASSERT(txn, XCURSOR_INITED(&cx.outer) &&
                         cx.outer.mc_xcursor->mx_db.md_entries > 1);
        rc = MDBX_EMULTIVAL;
+        if ((flags & MDBX_NOOVERWRITE) == 0) {
+          flags -= MDBX_CURRENT;
+          rc = cursor_del(&cx.outer, MDBX_ALLDUPS);
+        }
      }
    }
  }
--- a/src/internals.h
+++ b/src/internals.h
@@ -1482,6 +1482,7 @@ struct MDBX_env {
  int me_valgrind_handle;
 #endif
 #if defined(MDBX_USE_VALGRIND) || defined(__SANITIZE_ADDRESS__)
+  MDBX_atomic_uint32_t me_ignore_EDEADLK;
  pgno_t me_poison_edge;
 #endif /* MDBX_USE_VALGRIND || __SANITIZE_ADDRESS__ */

--- a/src/lck-posix.c
+++ b/src/lck-posix.c
@@ -822,6 +822,11 @@ __cold static int mdbx_ipclock_failed(MDBX_env *env, osal_ipclock_t *ipc,
 #error "FIXME"
 #endif /* MDBX_LOCKING */

+#if defined(MDBX_USE_VALGRIND) || defined(__SANITIZE_ADDRESS__)
+  if (rc == EDEADLK && atomic_load32(&env->me_ignore_EDEADLK, mo_Relaxed) > 0)
+    return rc;
+#endif /* MDBX_USE_VALGRIND || __SANITIZE_ADDRESS__ */
+
  ERROR("mutex (un)lock failed, %s", mdbx_strerror(err));
  if (rc != EDEADLK)
    env->me_flags |= MDBX_FATAL_ERROR;
--- a/src/man1/mdbx_chk.1
+++ b/src/man1/mdbx_chk.1
@@ -1,6 +1,6 @@
 .\" Copyright 2015-2023 Leonid Yuriev <leo@yuriev.ru>.
 .\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
-.TH MDBX_CHK 1 "2023-04-29" "MDBX 0.12.6"
+.TH MDBX_CHK 1 "2023-10-17" "MDBX 0.12.8"
 .SH NAME
 mdbx_chk \- MDBX checking tool
 .SH SYNOPSIS
--- a/src/man1/mdbx_copy.1
+++ b/src/man1/mdbx_copy.1
@@ -2,7 +2,7 @@
 .\" Copyright 2015,2016 Peter-Service R&D LLC <http://billing.ru/>.
 .\" Copyright 2012-2015 Howard Chu, Symas Corp. All Rights Reserved.
 .\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
-.TH MDBX_COPY 1 "2023-04-29" "MDBX 0.12.6"
+.TH MDBX_COPY 1 "2023-10-17" "MDBX 0.12.8"
 .SH NAME
 mdbx_copy \- MDBX environment copy tool
 .SH SYNOPSIS
--- a/src/man1/mdbx_drop.1
+++ b/src/man1/mdbx_drop.1
@@ -1,7 +1,7 @@
 .\" Copyright 2021-2023 Leonid Yuriev <leo@yuriev.ru>.
 .\" Copyright 2014-2021 Howard Chu, Symas Corp. All Rights Reserved.
 .\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
-.TH MDBX_DROP 1 "2023-04-29" "MDBX 0.12.6"
+.TH MDBX_DROP 1 "2023-10-17" "MDBX 0.12.8"
 .SH NAME
 mdbx_drop \- MDBX database delete tool
 .SH SYNOPSIS
--- a/src/man1/mdbx_dump.1
+++ b/src/man1/mdbx_dump.1
@@ -2,7 +2,7 @@
 .\" Copyright 2015,2016 Peter-Service R&D LLC <http://billing.ru/>.
 .\" Copyright 2014-2015 Howard Chu, Symas Corp. All Rights Reserved.
 .\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
-.TH MDBX_DUMP 1 "2023-04-29" "MDBX 0.12.6"
+.TH MDBX_DUMP 1 "2023-10-17" "MDBX 0.12.8"
 .SH NAME
 mdbx_dump \- MDBX environment export tool
 .SH SYNOPSIS
--- a/src/man1/mdbx_load.1
+++ b/src/man1/mdbx_load.1
@@ -2,7 +2,7 @@
 .\" Copyright 2015,2016 Peter-Service R&D LLC <http://billing.ru/>.
 .\" Copyright 2014-2015 Howard Chu, Symas Corp. All Rights Reserved.
 .\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
-.TH MDBX_LOAD 1 "2023-04-29" "MDBX 0.12.6"
+.TH MDBX_LOAD 1 "2023-10-17" "MDBX 0.12.8"
 .SH NAME
 mdbx_load \- MDBX environment import tool
 .SH SYNOPSIS
--- a/src/man1/mdbx_stat.1
+++ b/src/man1/mdbx_stat.1
@@ -2,7 +2,7 @@
 .\" Copyright 2015,2016 Peter-Service R&D LLC <http://billing.ru/>.
 .\" Copyright 2012-2015 Howard Chu, Symas Corp. All Rights Reserved.
 .\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
-.TH MDBX_STAT 1 "2023-04-29" "MDBX 0.12.6"
+.TH MDBX_STAT 1 "2023-10-17" "MDBX 0.12.8"
 .SH NAME
 mdbx_stat \- MDBX environment status tool
 .SH SYNOPSIS
--- a/src/mdbx.c++
+++ b/src/mdbx.c++
@@ -233,6 +233,10 @@ namespace mdbx {
      "into an incompatible memory allocation scheme.");
 }

+[[noreturn]] __cold void throw_bad_value_size() {
+  throw bad_value_size(MDBX_BAD_VALSIZE);
+}
+
 __cold exception::exception(const ::mdbx::error &error) noexcept
    : base(error.what()), error_(error) {}

@@ -483,6 +487,109 @@ bool slice::is_printable(bool disable_utf8) const noexcept {
  return true;
 }

+#ifdef MDBX_U128_TYPE
+MDBX_U128_TYPE slice::as_uint128() const {
+  static_assert(sizeof(MDBX_U128_TYPE) == 16, "WTF?");
+  if (size() == 16) {
+    MDBX_U128_TYPE r;
+    memcpy(&r, data(), sizeof(r));
+    return r;
+  } else
+    return as_uint64();
+}
+#endif /* MDBX_U128_TYPE */
+
+uint64_t slice::as_uint64() const {
+  static_assert(sizeof(uint64_t) == 8, "WTF?");
+  if (size() == 8) {
+    uint64_t r;
+    memcpy(&r, data(), sizeof(r));
+    return r;
+  } else
+    return as_uint32();
+}
+
+uint32_t slice::as_uint32() const {
+  static_assert(sizeof(uint32_t) == 4, "WTF?");
+  if (size() == 4) {
+    uint32_t r;
+    memcpy(&r, data(), sizeof(r));
+    return r;
+  } else
+    return as_uint16();
+}
+
+uint16_t slice::as_uint16() const {
+  static_assert(sizeof(uint16_t) == 2, "WTF?");
+  if (size() == 2) {
+    uint16_t r;
+    memcpy(&r, data(), sizeof(r));
+    return r;
+  } else
+    return as_uint8();
+}
+
+uint8_t slice::as_uint8() const {
+  static_assert(sizeof(uint8_t) == 1, "WTF?");
+  if (size() == 1)
+    return *static_cast<const uint8_t *>(data());
+  else if (size() == 0)
+    return 0;
+  else
+    MDBX_CXX20_UNLIKELY throw_bad_value_size();
+}
+
+#ifdef MDBX_I128_TYPE
+MDBX_I128_TYPE slice::as_int128() const {
+  static_assert(sizeof(MDBX_I128_TYPE) == 16, "WTF?");
+  if (size() == 16) {
+    MDBX_I128_TYPE r;
+    memcpy(&r, data(), sizeof(r));
+    return r;
+  } else
+    return as_int64();
+}
+#endif /* MDBX_I128_TYPE */
+
+int64_t slice::as_int64() const {
+  static_assert(sizeof(int64_t) == 8, "WTF?");
+  if (size() == 8) {
+    uint64_t r;
+    memcpy(&r, data(), sizeof(r));
+    return r;
+  } else
+    return as_int32();
+}
+
+int32_t slice::as_int32() const {
+  static_assert(sizeof(int32_t) == 4, "WTF?");
+  if (size() == 4) {
+    int32_t r;
+    memcpy(&r, data(), sizeof(r));
+    return r;
+  } else
+    return as_int16();
+}
+
+int16_t slice::as_int16() const {
+  static_assert(sizeof(int16_t) == 2, "WTF?");
+  if (size() == 2) {
+    int16_t r;
+    memcpy(&r, data(), sizeof(r));
+    return r;
+  } else
+    return as_int8();
+}
+
+int8_t slice::as_int8() const {
+  if (size() == 1)
+    return *static_cast<const int8_t *>(data());
+  else if (size() == 0)
+    return 0;
+  else
+    MDBX_CXX20_UNLIKELY throw_bad_value_size();
+}
+
 //------------------------------------------------------------------------------

 char *to_hex::write_bytes(char *__restrict const dest, size_t dest_size) const {
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -80,6 +80,13 @@ if(UNIX AND NOT SUBPROJECT)
      set_target_properties(test_extra_maindb_ordinal PROPERTIES
        CXX_STANDARD ${MDBX_CXX_STANDARD} CXX_STANDARD_REQUIRED ON)
    endif()
+    add_executable(test_extra_dupfixed_multiple extra/dupfixed_multiple.c++)
+    target_include_directories(test_extra_dupfixed_multiple PRIVATE "${PROJECT_SOURCE_DIR}")
+    target_link_libraries(test_extra_dupfixed_multiple ${TOOL_MDBX_LIB})
+    if(MDBX_CXX_STANDARD)
+      set_target_properties(test_extra_dupfixed_multiple PROPERTIES
+        CXX_STANDARD ${MDBX_CXX_STANDARD} CXX_STANDARD_REQUIRED ON)
+    endif()
  endif()
 endif()

@@ -159,4 +166,12 @@ else()
      REQUIRED_FILES uniq_nested.db-copy)
  endif()

+  if(UNIX AND NOT SUBPROJECT)
+    add_test(NAME extra_upsert_alldups COMMAND test_extra_upsert_alldups)
+    if(MDBX_BUILD_CXX)
+      add_test(NAME extra_maindb_ordinal COMMAND test_extra_maindb_ordinal)
+      add_test(NAME extra_dupfixed_multiple COMMAND test_extra_dupfixed_multiple)
+    endif()
+  endif()
+
 endif()
--- a/test/extra/dupfixed_multiple.c++
+++ b/test/extra/dupfixed_multiple.c++
@@ -0,0 +1,210 @@
+#include "mdbx.h++"
+#include <array>
+#include <iostream>
+#include <unistd.h>
+
+int main(int argc, const char *argv[]) {
+  (void)argc;
+  (void)argv;
+
+  unlink("." MDBX_DATANAME);
+  unlink("." MDBX_LOCKNAME);
+
+  mdbx::env_managed env(".", mdbx::env_managed::create_parameters(),
+                        mdbx::env::operate_parameters());
+
+  using buffer =
+      mdbx::buffer<mdbx::default_allocator, mdbx::default_capacity_policy>;
+  auto txn = env.start_write();
+  auto map = txn.create_map(nullptr, mdbx::key_mode::ordinal,
+                            mdbx::value_mode::multi_ordinal);
+
+  txn.insert(map, buffer::key_from_u64(21), buffer::key_from_u64(18));
+  txn.insert(map, buffer::key_from_u64(7), buffer::key_from_u64(19));
+  txn.insert(map, buffer::key_from_u64(22), buffer::key_from_u64(17));
+  txn.insert(map, buffer::key_from_u64(26), buffer::key_from_u64(13));
+  txn.insert(map, buffer::key_from_u64(24), buffer::key_from_u64(15));
+  txn.insert(map, buffer::key_from_u64(23), buffer::key_from_u64(16));
+  txn.insert(map, buffer::key_from_u64(25), buffer::key_from_u64(14));
+  txn.insert(map, buffer::key_from_u64(27), buffer::key_from_u64(12));
+  txn.commit();
+
+  txn = env.start_read();
+  auto cursor = txn.open_cursor(map);
+  if (cursor.to_first().value.as_uint64() != 19 ||
+      cursor.to_next().value.as_uint64() != 18 ||
+      cursor.to_next().value.as_uint64() != 17 ||
+      cursor.to_next().value.as_uint64() != 16 ||
+      cursor.to_next().value.as_uint64() != 15 ||
+      cursor.to_next().value.as_uint64() != 14 ||
+      cursor.to_next().value.as_uint64() != 13 ||
+      cursor.to_next().value.as_uint64() != 12 || cursor.to_next(false).done ||
+      !cursor.eof()) {
+    std::cerr << "Fail\n";
+    return EXIT_FAILURE;
+  }
+  txn.abort();
+
+  const uint64_t array[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 42, 17, 99, 0, 33, 333};
+  txn = env.start_write();
+  txn.put_multiple(map, buffer::key_from_u64(13), array + 3, 4, mdbx::upsert);
+  txn.put_multiple(map, buffer::key_from_u64(10), array + 0, 1, mdbx::upsert);
+  txn.put_multiple(map, buffer::key_from_u64(12), array + 2, 3, mdbx::upsert);
+  txn.put_multiple(map, buffer::key_from_u64(15), array + 5, 6, mdbx::upsert);
+  txn.put_multiple(map, buffer::key_from_u64(14), array + 4, 5, mdbx::upsert);
+  txn.put_multiple(map, buffer::key_from_u64(11), array + 1, 2, mdbx::upsert);
+  txn.put_multiple(map, buffer::key_from_u64(16), array + 6, 7, mdbx::upsert);
+  txn.commit();
+
+  txn = env.start_read();
+  cursor = txn.open_cursor(map);
+  if (/* key = 7 */ cursor.to_first().value.as_uint64() != 19 ||
+
+      /* key = 10: 1 элемент */
+      cursor.to_next().value.as_uint64() != 1 ||
+
+      /* key = 11: 2 элемента, пропуск 1 */
+      cursor.to_next().value.as_uint64() != 2 ||
+      cursor.to_next().value.as_uint64() != 3 ||
+
+      /* key = 12: 3 элемента, пропуск 2 */
+      cursor.to_next().value.as_uint64() != 3 ||
+      cursor.to_next().value.as_uint64() != 4 ||
+      cursor.to_next().value.as_uint64() != 5 ||
+
+      /* key = 13: 4 элемента, пропуск 3 */
+      cursor.to_next().value.as_uint64() != 4 ||
+      cursor.to_next().value.as_uint64() != 5 ||
+      cursor.to_next().value.as_uint64() != 6 ||
+      cursor.to_next().value.as_uint64() != 7 ||
+
+      /* key = 14: 5 элементов, пропуск 4 */
+      cursor.to_next().value.as_uint64() != 5 ||
+      cursor.to_next().value.as_uint64() != 6 ||
+      cursor.to_next().value.as_uint64() != 7 ||
+      cursor.to_next().value.as_uint64() != 8 ||
+      cursor.to_next().value.as_uint64() != 9 ||
+
+      /* key = 15: 6 элементов, пропуск 5 */
+      cursor.to_next().value.as_uint64() != 6 ||
+      cursor.to_next().value.as_uint64() != 7 ||
+      cursor.to_next().value.as_uint64() != 8 ||
+      cursor.to_next().value.as_uint64() != 9 ||
+      cursor.to_next().value.as_uint64() != 17 ||
+      cursor.to_next().value.as_uint64() != 42 ||
+
+      /* key = 16: 7 элементов, пропуск 6 */
+      cursor.to_next().value.as_uint64() != 0 ||
+      cursor.to_next().value.as_uint64() != 7 ||
+      cursor.to_next().value.as_uint64() != 8 ||
+      cursor.to_next().value.as_uint64() != 9 ||
+      cursor.to_next().value.as_uint64() != 17 ||
+      cursor.to_next().value.as_uint64() != 42 ||
+      cursor.to_next().value.as_uint64() != 99 ||
+
+      /* key = 21 */ cursor.to_next().value.as_uint64() != 18 ||
+      /* key = 22 */ cursor.to_next().value.as_uint64() != 17 ||
+      /* key = 23 */ cursor.to_next().value.as_uint64() != 16 ||
+      /* key = 24 */ cursor.to_next().value.as_uint64() != 15 ||
+      /* key = 25 */ cursor.to_next().value.as_uint64() != 14 ||
+      /* key = 26 */ cursor.to_next().value.as_uint64() != 13 ||
+      /* key = 27 */ cursor.to_next().value.as_uint64() != 12 ||
+      cursor.to_next(false).done || !cursor.eof()) {
+    std::cerr << "Fail\n";
+    return EXIT_FAILURE;
+  }
+  txn.abort();
+
+  txn = env.start_write();
+  txn.put_multiple(map, buffer::key_from_u64(7), array + 3, 4, mdbx::update);
+  txn.upsert(map, buffer::key_from_u64(10), buffer::key_from_u64(14));
+  txn.put_multiple(map, buffer::key_from_u64(11), array + 4, 5, mdbx::upsert);
+  txn.put_multiple(map, buffer::key_from_u64(12), array + 0, 1, mdbx::update);
+  txn.update(map, buffer::key_from_u64(13), buffer::key_from_u64(18));
+  txn.put_multiple(map, buffer::key_from_u64(14), array + 2, 3, mdbx::update);
+  txn.update(map, buffer::key_from_u64(15), buffer::key_from_u64(13));
+  txn.put_multiple(map, buffer::key_from_u64(16), array + 6, 9, mdbx::update);
+  txn.update(map, buffer::key_from_u64(21), buffer::key_from_u64(17));
+  txn.update(map, buffer::key_from_u64(22), buffer::key_from_u64(15));
+  txn.put_multiple(map, buffer::key_from_u64(23), array + 1, 2, mdbx::update);
+  txn.update(map, buffer::key_from_u64(24), buffer::key_from_u64(16));
+  txn.put_multiple(map, buffer::key_from_u64(25), array + 5, 6, mdbx::update);
+  txn.upsert(map, buffer::key_from_u64(26), buffer::key_from_u64(12));
+  txn.put_multiple(map, buffer::key_from_u64(27), array + 12, 3, mdbx::update);
+  txn.commit();
+
+  txn = env.start_read();
+  cursor = txn.open_cursor(map);
+  if (/* key = 7 */
+      cursor.to_first().value.as_uint64() != 4 ||
+      cursor.to_next().value.as_uint64() != 5 ||
+      cursor.to_next().value.as_uint64() != 6 ||
+      cursor.to_next().value.as_uint64() != 7 ||
+
+      /* key = 10: 1 элемент */
+      cursor.to_next().value.as_uint64() != 1 ||
+      /* +1 upsert */
+      cursor.to_next().value.as_uint64() != 14 ||
+
+      /* key = 11: 2 элемента, пропуск 1 */
+      cursor.to_next().value.as_uint64() != 2 ||
+      cursor.to_next().value.as_uint64() != 3 ||
+      /* +5 элементов, пропуск 4 */
+      cursor.to_next().value.as_uint64() != 5 ||
+      cursor.to_next().value.as_uint64() != 6 ||
+      cursor.to_next().value.as_uint64() != 7 ||
+      cursor.to_next().value.as_uint64() != 8 ||
+      cursor.to_next().value.as_uint64() != 9 ||
+
+      /* key = 12: 1 элемент */
+      cursor.to_next().value.as_uint64() != 1 ||
+      /* key = 13 */ cursor.to_next().value.as_uint64() != 18 ||
+
+      /* key = 14: 3 элемента, пропуск 2 */
+      cursor.to_next().value.as_uint64() != 3 ||
+      cursor.to_next().value.as_uint64() != 4 ||
+      cursor.to_next().value.as_uint64() != 5 ||
+
+      /* key = 15 */ cursor.to_next().value.as_uint64() != 13 ||
+
+      /* key = 16: 9 элементов, пропуск 6 */
+      cursor.to_next().value.as_uint64() != 0 ||
+      cursor.to_next().value.as_uint64() != 7 ||
+      cursor.to_next().value.as_uint64() != 8 ||
+      cursor.to_next().value.as_uint64() != 9 ||
+      cursor.to_next().value.as_uint64() != 17 ||
+      cursor.to_next().value.as_uint64() != 33 ||
+      cursor.to_next().value.as_uint64() != 42 ||
+      cursor.to_next().value.as_uint64() != 99 ||
+      cursor.to_next().value.as_uint64() != 333 ||
+
+      /* key = 21 */ cursor.to_next().value.as_uint64() != 17 ||
+      /* key = 22 */ cursor.to_next().value.as_uint64() != 15 ||
+      /* key = 23: 2 элемента, пропуск 1 */
+      cursor.to_next().value.as_uint64() != 2 ||
+      cursor.to_next().value.as_uint64() != 3 ||
+      /* key = 24 */ cursor.to_next().value.as_uint64() != 16 ||
+      /* key = 25: 6 элемента, пропуск 5 */
+      cursor.to_next().value.as_uint64() != 6 ||
+      cursor.to_next().value.as_uint64() != 7 ||
+      cursor.to_next().value.as_uint64() != 8 ||
+      cursor.to_next().value.as_uint64() != 9 ||
+      cursor.to_next().value.as_uint64() != 17 ||
+      cursor.to_next().value.as_uint64() != 42 ||
+
+      /* key = 26, 1+1 upsert */
+      cursor.to_next().value.as_uint64() != 12 ||
+      cursor.to_next().value.as_uint64() != 13 ||
+
+      /* key = 27: 3 элемента, пропуск 12 */
+      cursor.to_next().value.as_uint64() != 0 ||
+      cursor.to_next().value.as_uint64() != 33 ||
+      cursor.to_next().value.as_uint64() != 333 ||
+
+      cursor.to_next(false).done || !cursor.eof()) {
+    std::cerr << "Fail\n";
+    return EXIT_FAILURE;
+  }
+  std::cout << "OK\n";
+  return EXIT_SUCCESS;
+}
--- a/test/extra/upsert_alldups.c
+++ b/test/extra/upsert_alldups.c
@@ -12,8 +12,8 @@
 #include <unistd.h>

 static int dump(MDBX_cursor *cur) {
-  MDBX_val key = {};
-  MDBX_val data = {};
+  MDBX_val key = {NULL, 0};
+  MDBX_val data = {NULL, 0};
  int rc = mdbx_cursor_get(cur, &key, &data, MDBX_FIRST);

  while (rc == 0) {
@@ -25,15 +25,14 @@ static int dump(MDBX_cursor *cur) {
 }

 static int clear(MDBX_cursor *cur) {
-  MDBX_val key = {};
-  MDBX_val data = {};
+  MDBX_val key = {NULL, 0};
+  MDBX_val data = {NULL, 0};
  int rc = mdbx_cursor_get(cur, &key, &data, MDBX_FIRST);

  while (rc == 0) {
    rc = mdbx_cursor_del(cur, MDBX_ALLDUPS);
-    if (rc) {
+    if (rc)
      return rc;
-    }
    rc = mdbx_cursor_get(cur, &key, &data, MDBX_NEXT);
  }
  return (rc == MDBX_NOTFOUND) ? 0 : rc;
@@ -183,6 +182,7 @@ int main(int argc, const char *argv[]) {
    errmsg = "failed to mdbx_txn_commit: %s\n";
    goto Fail;
  }
+  mdbx_cursor_close(cur);
  if ((rc = mdbx_env_close(env))) {
    errmsg = "failed to mdbx_env_close: %s\n";
    goto Fail;