libmdbx: another important bugfix

17 files changed, 162 insertions, 481 deletions

diff --git a/libs/libmdbx/src/CMakeLists.txt b/libs/libmdbx/src/CMakeLists.txt
deleted file mode 100644
index b664075556..0000000000
--- a/libs/libmdbx/src/CMakeLists.txt
+++ /dev/null
@@ -1,193 +0,0 @@
-cmake_minimum_required(VERSION 2.8.7)
-set(TARGET mdbx)
-project(${TARGET})
-
-message(WARNING "
-***************************************************************
-  MDBX is under active development, database format and API
-  aren't stable at least until 2018Q3. New version won't be
-  backwards compatible. Main focus of the rework is to provide
-  clear and robust API and new features.
-***************************************************************
-")
-
-set(MDBX_VERSION_MAJOR 0)
-set(MDBX_VERSION_MINOR 1)
-set(MDBX_VERSION_RELEASE 3)
-set(MDBX_VERSION_REVISION 1)
-
-set(MDBX_VERSION_STRING ${MDBX_VERSION_MAJOR}.${MDBX_VERSION_MINOR}.${MDBX_VERSION_RELEASE})
-
-enable_language(C)
-enable_language(CXX)
-
-set(CMAKE_CXX_STANDARD 11)
-set(CMAKE_CXX_STANDARD_REQUIRED on)
-
-add_definitions(-DNDEBUG=1 -DMDBX_DEBUG=0 -DLIBMDBX_EXPORTS=1 -D_GNU_SOURCE=1)
-
-find_package(Threads REQUIRED)
-
-get_directory_property(hasParent PARENT_DIRECTORY)
-if(hasParent)
-  set(STANDALONE_BUILD 0)
-else()
-  set(STANDALONE_BUILD 1)
-  enable_testing()
-
-  if (CMAKE_C_COMPILER_ID MATCHES GNU)
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O2")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g3")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Werror")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wextra")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -ffunction-sections")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fvisibility=hidden")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu11")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -pthread")
-  endif()
-
-  if (CMAKE_CXX_COMPILER_ID MATCHES GNU)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -W")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wpointer-arith")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-sign-compare")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wformat-security")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Woverloaded-virtual")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wwrite-strings")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fmax-errors=20")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fvisibility=hidden")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-unused-parameter -Wunused-function -Wunused-variable -Wunused-value -Wmissing-declarations")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-missing-field-initializers")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wcast-qual")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -ggdb")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-omit-frame-pointer")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-strict-aliasing")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -finline-functions-called-once")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-packed-bitfield-compat")
-
-    set(CMAKE_CXX_FLAGS_DEBUG "-O0 -g3")
-    set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-O3 -g3")
-  endif()
-
-  if (COVERAGE)
-    if (NOT "${CMAKE_BUILD_TYPE}" STREQUAL "Debug")
-      message(FATAL_ERROR "Coverage requires -DCMAKE_BUILD_TYPE=Debug Current value=${CMAKE_BUILD_TYPE}")
-    endif()
-
-    message(STATUS "Setting coverage compiler flags")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -ggdb3 -O0 --coverage -fprofile-arcs -ftest-coverage")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS}     -g -ggdb3 -O0 --coverage -fprofile-arcs -ftest-coverage")
-    add_definitions(-DCOVERAGE_TEST)
-  endif()
-
-  if (NOT TRAVIS)
-    set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -fsanitize=address -fsanitize=leak -fstack-protector-strong -static-libasan")
-  endif()
-endif()
-
-set(${TARGET}_SRC
-  mdbx.h
-  src/bits.h
-  src/defs.h
-  src/lck-posix.c
-  src/mdbx.c
-  src/osal.c
-  src/osal.h
-  src/version.c
-  )
-
-add_library(${TARGET}_STATIC STATIC
-  ${${TARGET}_SRC}
-  )
-
-add_library(${TARGET} ALIAS ${TARGET}_STATIC)
-
-add_library(${TARGET}_SHARED SHARED
-  ${${TARGET}_SRC}
-  )
-
-set_target_properties(${TARGET}_SHARED PROPERTIES
-  VERSION ${MDBX_VERSION_STRING}
-  SOVERSION ${MDBX_VERSION_MAJOR}
-  OUTPUT_NAME ${TARGET}
-  CLEAN_DIRECT_OUTPUT 1
-  )
-
-set_target_properties(${TARGET}_STATIC PROPERTIES
-  VERSION ${MDBX_VERSION_STRING}
-  SOVERSION ${MDBX_VERSION_MAJOR}
-  OUTPUT_NAME ${TARGET}
-  CLEAN_DIRECT_OUTPUT 1
-  )
-
-target_include_directories(${TARGET}_STATIC PUBLIC
-  ${CMAKE_CURRENT_SOURCE_DIR})
-target_include_directories(${TARGET}_SHARED PUBLIC
-  ${CMAKE_CURRENT_SOURCE_DIR})
-
-target_link_libraries(${TARGET}_STATIC ${CMAKE_THREAD_LIBS_INIT})
-target_link_libraries(${TARGET}_SHARED ${CMAKE_THREAD_LIBS_INIT})
-if(UNIX AND NOT APPLE)
-  target_link_libraries(${TARGET}_STATIC rt)
-  target_link_libraries(${TARGET}_SHARED rt)
-endif()
-
-install(TARGETS ${TARGET}_STATIC DESTINATION ${CMAKE_INSTALL_PREFIX}/lib64 COMPONENT mdbx)
-install(TARGETS ${TARGET}_SHARED DESTINATION ${CMAKE_INSTALL_PREFIX}/lib64 COMPONENT mdbx)
-install(FILES mdbx.h DESTINATION ${CMAKE_INSTALL_PREFIX}/include COMPONENT mdbx-devel)
-
-add_subdirectory(src/tools)
-add_subdirectory(test)
-add_subdirectory(test/pcrf)
-add_subdirectory(tutorial)
-
-##############################################################################
-
-set(CPACK_GENERATOR "RPM")
-set(CPACK_RPM_COMPONENT_INSTALL ON)
-
-# Version
-if (NOT "$ENV{BUILD_NUMBER}" STREQUAL "")
-  set(CPACK_PACKAGE_RELEASE $ENV{BUILD_NUMBER})
-else()
-  if (NOT "$ENV{CI_PIPELINE_ID}" STREQUAL "")
-    set(CPACK_PACKAGE_RELEASE $ENV{CI_PIPELINE_ID})
-  else()
-    set(CPACK_PACKAGE_RELEASE 1)
-  endif()
-endif()
-set(CPACK_RPM_PACKAGE_RELEASE ${CPACK_PACKAGE_RELEASE})
-
-set(CPACK_PACKAGE_VERSION ${MDBX_VERSION_STRING})
-set(CPACK_PACKAGE_VERSION_FULL ${CPACK_PACKAGE_VERSION}-${CPACK_PACKAGE_RELEASE})
-
-set(CPACK_RPM_mdbx-devel_PACKAGE_REQUIRES "mdbx = ${CPACK_PACKAGE_VERSION}")
-
-set(CPACK_RPM_SPEC_INSTALL_POST "/bin/true")
-set(CPACK_RPM_mdbx_PACKAGE_NAME mdbx)
-set(CPACK_RPM_mdbx-devel_PACKAGE_NAME mdbx-devel)
-set(CPACK_PACKAGE_DESCRIPTION_SUMMARY "The revised and extended descendant of Symas LMDB")
-
-set(CPACK_PACKAGE_VENDOR "???")
-set(CPACK_PACKAGE_CONTACT "Vladimir Romanov")
-set(CPACK_PACKAGE_RELOCATABLE false)
-set(CPACK_RPM_PACKAGE_ARCHITECTURE "x86_64")
-set(CPACK_RPM_PACKAGE_REQUIRES "")
-set(CPACK_RPM_PACKAGE_GROUP "Applications/Database")
-
-set(CPACK_RPM_mdbx_FILE_NAME "${CPACK_RPM_mdbx_PACKAGE_NAME}-${CPACK_PACKAGE_VERSION_FULL}.${CPACK_RPM_PACKAGE_ARCHITECTURE}.rpm")
-set(CPACK_RPM_mdbx-devel_FILE_NAME "${CPACK_RPM_mdbx-devel_PACKAGE_NAME}-${CPACK_PACKAGE_VERSION_FULL}.${CPACK_RPM_PACKAGE_ARCHITECTURE}.rpm")
-
-set(CPACK_RPM_EXCLUDE_FROM_AUTO_FILELIST_ADDITION
-  /usr/local
-  /usr/local/bin
-  /usr/local/lib64
-  /usr/local/include
-  /usr/local/man
-  /usr/local/man/man1
-  )
-
-include(CPack)
diff --git a/libs/libmdbx/src/TODO.md b/libs/libmdbx/src/TODO.md
deleted file mode 100644
index 810b18dc4a..0000000000
--- a/libs/libmdbx/src/TODO.md
+++ /dev/null
@@ -1,89 +0,0 @@
-Допеределки
-===========
-- [ ] Перевод mdbx-tools на С++ и сборка для Windows.
-- [ ] Переход на CMake, замена заглушек mdbx_version и mdbx_build.
-- [ ] Актуализация README.md
-- [ ] Переход на C++11, добавление #pramga detect_mismatch().
-- [ ] Убрать MDB_DEBUG (всегда: логирование важный ситуаций и ошибок, опционально: включение ассертов и трассировка).
-- [ ] Заменить mdbx_debug на mdbx_trace, и почистить...
-- [ ] Заметить максимум assert() на mdbx_assert(env, ...).
-
-Качество и CI
-=============
-- [ ] Добавить в CI linux сборки для 32-битных таргетов.
-
-Доработки API
-=============
-- [ ] Поправить/Добавить описание нового API.
-- [ ] Добавить возможность "подбора" режима для mdbx_env_open().
-- [ ] Переименовать в API: env->db, db->tbl.
-
-Тесты
-=====
-- [ ] Тестирование поддержки lockless-режима.
-- [x] Додумать имя и размещение тестовой БД по-умолчанию.
-- [ ] Реализовать cleanup в тесте.
-- [ ] usage для теста.
-- [ ] Логирование в файл, плюс более полный progress bar.
-- [ ] Опция игнорирования (пропуска части теста) при переполнении БД.
-- [ ] Базовый бенчмарк.
-
-Развитие
-========
-- [ ] Отслеживание времени жизни DBI-хендлов.
-- [ ] Отрефакторить mdbx_freelist_save().
-- [ ] Хранить "свободный хвост" не связанный с freeDB в META.
-- [x] Возврат выделенных страниц в unallocated tail-pool.
-- [ ] Валидатор страниц БД по номеру транзакции:
-      ~0 при переработке и номер транзакции при выделении,
-      проверять что этот номер больше головы реклайминга и не-больше текущей транзакции.
-- [ ] Размещение overflow-pages в отдельном mmap/файле с собственной геометрией.
-- [ ] Зафиксировать формат БД.
-- [ ] Валидатор страниц по CRC32, плюс контроль номер транзакии под модулю 2^32.
-- [ ] Валидатор страниц по t1ha c контролем снимков/версий БД на основе Merkle Tree.
-- [ ] Возможность хранения ключей внутри data (libfptu).
-- [ ] Асинхронная фиксация (https://github.com/leo-yuriev/libmdbx/issues/5).
-- [ ] (Пере)Выделять память под IDL-списки с учетом реального кол-ва страниц, т.е. max(MDB_IDL_UM_MAX/MDB_IDL_UM_MAX, npages).
-
------------------------------------------------------------------------
-
-Сделано
-=======
-- [x] разделение errno и GetLastError().
-- [x] CI посредством AppVeyor.
-- [x] тест конкурентного доступа.
-- [x] тест основного функционала (заменить текущий треш).
-- [x] uint32/uint64 в структурах.
-- [x] Завершить переименование.
-- [x] Макросы версионности, сделать как в fpta (cmake?).
-- [x] Попробовать убрать yield (или что там с местом?).
-- [x] trinity для copy/compaction.
-- [x] trinity для mdbx_chk и mdbx_stat.
-- [x] проверки с mdbx_meta_eq.
-- [x] Не проверять режим при открытии в readonly.
-- [x] Поправить выбор tail в mdbx_chk.
-- [x] Там-же проверять позицию реклайминга.
-- [x] поправить проблему открытия после READ-ONLY.
-- [x] static-assertы на размер/выравнивание lck, meta и т.п.
-- [x] Зачистить size_t.
-- [x] Добавить локи вокруг dbi.
-- [x] Привести в порядок volatile.
-- [x] контроль meta.mapsize.
-- [x] переработка формата: заголовки страниц, meta, clk...
-- [x] зачистка Doxygen и бесполезных комментариев.
-- [x] Добавить поле типа контрольной суммы.
-- [x] Добавить поле/флаг размера pgno_t.
-- [x] Поменять сигнатуры.
-- [x] Добавить мета-страницы в coredump, проверить lck.
-- [x] Сделать список для txnid_t, кода sizeof(txnid_t) > sizeof(pgno_t) и вернуть размер pgno_t.
-- [x] Избавиться от умножения на размер страницы (заменить на сдвиг).
-- [x] Устранение всех предупреждений (в том числе под Windows).
-- [x] Добавить 'mti_reader_finished_flag'.
-- [x] Погасить все level4-warnings от MSVC, включить /WX.
-- [x] Проверка посредством Coverity с гашением всех дефектов.
-- [x] Полная матрица Windows-сборок (2013/2015/2017).
-- [x] Дать возможность задавать размер страницы при создании БД.
-- [x] Изменение mapsize через API с блокировкой и увеличением txn.
-- [x] Контроль размера страницы полного размера и кол-ва страниц при создании и обновлении.
-- [x] Инкрементальный mmap.
-- [x] Инкрементальное приращение размера (колбэк стратегии?).
diff --git a/libs/libmdbx/src/build.sh b/libs/libmdbx/src/build.sh
deleted file mode 100644
index 5170882265..0000000000
--- a/libs/libmdbx/src/build.sh
+++ /dev/null
@@ -1,18 +0,0 @@
-#!/bin/bash
-set -e
-CONFIG=$1
-
-if [[ -z "${CONFIG}" ]]; then
-    CONFIG=Debug
-fi
-if [[ -r /opt/rh/devtoolset-6/enable ]]; then
-    source /opt/rh/devtoolset-6/enable
-fi
-#rm -f -r build || true
-mkdir -p cmake-build-${CONFIG}
-pushd  cmake-build-${CONFIG} &> /dev/null
-if [[ ! -r Makefile ]]; then
-    cmake .. -DCMAKE_BUILD_TYPE=${CONFIG}
-fi
-make -j8 || exit 1
-popd &> /dev/null
diff --git a/libs/libmdbx/src/mdbx.h b/libs/libmdbx/src/mdbx.h
index 2d0eeba949..8720f34ae0 100644
--- a/libs/libmdbx/src/mdbx.h
+++ b/libs/libmdbx/src/mdbx.h
@@ -1251,6 +1251,8 @@ LIBMDBX_API int mdbx_drop(MDBX_txn *txn, MDBX_dbi dbi, int del);
  *  - MDBX_EINVAL   - an invalid parameter was specified. */
 LIBMDBX_API int mdbx_get(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key,
                          MDBX_val *data);
+LIBMDBX_API int mdbx_get2(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key,
+                          MDBX_val *data);
 
 /* Store items into a database.
  *
diff --git a/libs/libmdbx/src/package.sh b/libs/libmdbx/src/package.sh
deleted file mode 100644
index d7f9ab297a..0000000000
--- a/libs/libmdbx/src/package.sh
+++ /dev/null
@@ -1,25 +0,0 @@
-#!/bin/bash
-set -e
-
-CONFIG=$1
-
-if [[ -z "${CONFIG}" ]]; then
-    CONFIG=Debug
-fi
-
-DIRNAME=`dirname ${BASH_SOURCE[0]}`
-DIRNAME=`readlink --canonicalize ${DIRNAME}`
-
-if [[ -r /opt/rh/devtoolset-6/enable ]]; then
-    source /opt/rh/devtoolset-6/enable
-fi
-
-mkdir -p cmake-build-${CONFIG}
-pushd  cmake-build-${CONFIG} &> /dev/null
-if [[ ! -r Makefile ]]; then
-    cmake .. -DCMAKE_BUILD_TYPE=${CONFIG}
-fi
-rm -f *.rpm
-make -j8 package || exit 1
-rm -f *-Unspecified.rpm
-popd &> /dev/null
diff --git a/libs/libmdbx/src/src/mdbx.c b/libs/libmdbx/src/src/mdbx.c
index 82e0959134..9cfeba8809 100644
--- a/libs/libmdbx/src/src/mdbx.c
+++ b/libs/libmdbx/src/src/mdbx.c
@@ -3680,6 +3680,25 @@ static int mdbx_update_gc(MDBX_txn *txn) {
   if (unlikely(rc != MDBX_SUCCESS))
     goto bailout;
 
+  txnid_t reclaiming_head_id = env->me_last_reclaimed;
+  if (unlikely(reclaiming_head_id == 0)) {
+    reclaiming_head_id = mdbx_find_oldest(txn) - 1;
+    MDBX_val key;
+    rc = mdbx_cursor_get(&mc, &key, NULL, MDBX_FIRST);
+    if (unlikely(rc != MDBX_SUCCESS)) {
+      if (rc != MDBX_NOTFOUND)
+        goto bailout;
+    } else if (unlikely(key.iov_len != sizeof(txnid_t))) {
+      rc = MDBX_CORRUPTED;
+      goto bailout;
+    } else {
+      txnid_t first_pg;
+      memcpy(&first_pg, key.iov_base, sizeof(txnid_t));
+      if (reclaiming_head_id >= first_pg)
+        reclaiming_head_id = first_pg - 1;
+    }
+  }
+
 retry:
   mdbx_trace(" >> restart");
   mdbx_tassert(txn, mdbx_pnl_check(env->me_reclaimed_pglist, true));
@@ -3687,7 +3706,7 @@ retry:
            filled_gc_slot = ~0u;
   txnid_t cleaned_gc_id = 0, head_gc_id = env->me_last_reclaimed
                                               ? env->me_last_reclaimed
-                                              : ~(txnid_t)0;
+                                              : reclaiming_head_id;
 
   if (unlikely(/* paranoia */ ++loop > 42)) {
     mdbx_error("too more loops %u, bailout", loop);
@@ -3963,7 +3982,7 @@ retry:
     if (0 >= (int)left)
       break;
 
-    const unsigned max_spread = 10;
+    const unsigned prefer_max_scatter = 257;
     txnid_t reservation_gc_id;
     if (lifo) {
       assert(txn->mt_lifo_reclaimed != NULL);
@@ -3976,7 +3995,7 @@ retry:
       }
 
       if (head_gc_id > 1 &&
-          MDBX_PNL_SIZE(txn->mt_lifo_reclaimed) < max_spread &&
+          MDBX_PNL_SIZE(txn->mt_lifo_reclaimed) < prefer_max_scatter &&
           left > ((unsigned)MDBX_PNL_SIZE(txn->mt_lifo_reclaimed) -
                   reused_gc_slots) *
                      env->me_maxgc_ov1page) {
@@ -3995,7 +4014,7 @@ retry:
         /* LY: freedb is empty, will look any free txn-id in high2low order. */
         do {
           --head_gc_id;
-          assert(MDBX_PNL_LAST(txn->mt_lifo_reclaimed) > head_gc_id);
+          mdbx_assert(env, MDBX_PNL_LAST(txn->mt_lifo_reclaimed) > head_gc_id);
           rc = mdbx_txl_append(&txn->mt_lifo_reclaimed, head_gc_id);
           if (unlikely(rc != MDBX_SUCCESS))
             goto bailout;
@@ -4005,7 +4024,7 @@ retry:
                      " to lifo-reclaimed, cleaned-gc-slot = %u",
                      dbg_prefix_mode, head_gc_id, cleaned_gc_slot);
         } while (head_gc_id > 1 &&
-                 MDBX_PNL_SIZE(txn->mt_lifo_reclaimed) < max_spread &&
+                 MDBX_PNL_SIZE(txn->mt_lifo_reclaimed) < prefer_max_scatter &&
                  left > ((unsigned)MDBX_PNL_SIZE(txn->mt_lifo_reclaimed) -
                          reused_gc_slots) *
                             env->me_maxgc_ov1page);
@@ -4045,7 +4064,10 @@ retry:
         if (chunk < env->me_maxgc_ov1page * 2)
           chunk /= 2;
         else {
-          const unsigned threshold = env->me_maxgc_ov1page * avail_gs_slots;
+          const unsigned threshold =
+              env->me_maxgc_ov1page * ((avail_gs_slots < prefer_max_scatter)
+                                           ? avail_gs_slots
+                                           : prefer_max_scatter);
           if (left < threshold)
             chunk = env->me_maxgc_ov1page;
           else {
@@ -4071,7 +4093,7 @@ retry:
 
             chunk = (avail >= tail) ? tail - span
                                     : (avail_gs_slots > 3 &&
-                                       reused_gc_slots < max_spread - 3)
+                                       reused_gc_slots < prefer_max_scatter - 3)
                                           ? avail - span
                                           : tail;
           }
@@ -4112,6 +4134,14 @@ retry:
     settled += chunk;
     mdbx_trace("%s.settled %u (+%u), continue", dbg_prefix_mode, settled,
                chunk);
+
+    if (txn->mt_lifo_reclaimed &&
+        unlikely(amount < MDBX_PNL_SIZE(env->me_reclaimed_pglist))) {
+      mdbx_notice("** restart: reclaimed-list growth %u -> %u", amount,
+                  (unsigned)MDBX_PNL_SIZE(env->me_reclaimed_pglist));
+      goto retry;
+    }
+
     continue;
   }
 
@@ -7142,6 +7172,41 @@ int mdbx_get(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data) {
   return mdbx_cursor_set(&cx.outer, key, data, MDBX_SET, &exact);
 }
 
+int mdbx_get2(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data) {
+  int exact = 0;
+  DKBUF;
+
+  mdbx_debug("===> get db %u key [%s]", dbi, DKEY(key));
+
+  if (unlikely(!key || !data || !txn))
+    return MDBX_EINVAL;
+
+  if (unlikely(txn->mt_signature != MDBX_MT_SIGNATURE))
+    return MDBX_EBADSIGN;
+
+  if (unlikely(txn->mt_owner != mdbx_thread_self()))
+    return MDBX_THREAD_MISMATCH;
+
+  if (unlikely(!TXN_DBI_EXIST(txn, dbi, DB_USRVALID)))
+    return MDBX_EINVAL;
+
+  if (unlikely(txn->mt_flags & MDBX_TXN_BLOCKED))
+    return MDBX_BAD_TXN;
+
+  MDBX_cursor_couple cx;
+  int rc = mdbx_cursor_init(&cx.outer, txn, dbi);
+  if (unlikely(rc != MDBX_SUCCESS))
+    return rc;
+
+  const int op =
+      (txn->mt_dbs[dbi].md_flags & MDBX_DUPSORT) ? MDBX_GET_BOTH : MDBX_SET_KEY;
+  rc = mdbx_cursor_set(&cx.outer, key, data, op, &exact);
+  if (unlikely(rc != MDBX_SUCCESS))
+    return rc;
+
+  return exact ? MDBX_SUCCESS : MDBX_RESULT_TRUE;
+}
+
 /* Find a sibling for a page.
  * Replaces the page at the top of the cursor's stack with the specified
  * sibling, if one exists.
@@ -7739,11 +7804,6 @@ int mdbx_cursor_get(MDBX_cursor *mc, MDBX_val *key, MDBX_val *data,
       return MDBX_INCOMPATIBLE;
   /* FALLTHRU */
   case MDBX_SET:
-#ifndef SLAPD_LMDB_LEGACY
-    if (op == MDBX_SET && unlikely(data != NULL))
-      return MDBX_EINVAL;
-#endif /* SLAPD_LMDB_LEGACY */
-  /* FALLTHRU */
   case MDBX_SET_KEY:
   case MDBX_SET_RANGE:
     if (unlikely(key == NULL))
@@ -8931,131 +8991,6 @@ static int __must_check_result mdbx_node_add_leaf(MDBX_cursor *mc,
   return MDBX_SUCCESS;
 }
 
-#if 0
-/* Add a node to the page pointed to by the cursor.
- * Set MDBX_TXN_ERROR on failure.
- *
- * [in] mc    The cursor for this operation.
- * [in] indx  The index on the page where the new node should be added.
- * [in] key   The key for the new node.
- * [in] data  The data for the new node, if any.
- * [in] pgno  The page number, if adding a branch node.
- * [in] flags Flags for the node.
- *
- * Returns 0 on success, non-zero on failure. Possible errors are:
- *
- * MDBX_ENOMEM    - failed to allocate overflow pages for the node.
- * MDBX_PAGE_FULL  - there is insufficient room in the page. This error
- *                  should never happen since all callers already calculate
- *                  the page's free space before calling this function. */
-static int mdbx_node_add(MDBX_cursor *mc, unsigned indx, const MDBX_val *key,
-                         MDBX_val *data, pgno_t pgno, unsigned flags) {
-  unsigned i;
-  size_t node_size = NODESIZE;
-  intptr_t room;
-  MDBX_node *node;
-  MDBX_page *mp = mc->mc_pg[mc->mc_top];
-  MDBX_page *ofp = NULL; /* overflow page */
-  void *ndata;
-
-  mdbx_cassert(mc, mp->mp_upper >= mp->mp_lower);
-
-  DKBUF;
-  mdbx_debug("add to %s %spage %" PRIaPGNO " index %i, data size %" PRIuPTR
-             " key size %" PRIuPTR " [%s]",
-             IS_LEAF(mp) ? "leaf" : "branch", IS_SUBP(mp) ? "sub-" : "",
-             mp->mp_pgno, indx, data ? data->iov_len : 0,
-             key ? key->iov_len : 0, DKEY(key));
-
-  room = (intptr_t)SIZELEFT(mp) - (intptr_t)sizeof(indx_t);
-  if (key != NULL)
-    node_size += key->iov_len;
-  if (IS_LEAF(mp)) {
-    mdbx_cassert(mc, key && data);
-    if (unlikely(F_ISSET(flags, F_BIGDATA))) {
-      /* Data already on overflow page. */
-      node_size += sizeof(pgno_t);
-    } else if (unlikely(node_size + data->iov_len >
-                        mc->mc_txn->mt_env->me_nodemax)) {
-      pgno_t ovpages = OVPAGES(mc->mc_txn->mt_env, data->iov_len);
-      int rc;
-      /* Put data on overflow page. */
-      mdbx_debug("data size is %" PRIuPTR ", node would be %" PRIuPTR
-                 ", put data on overflow page",
-                 data->iov_len, node_size + data->iov_len);
-      node_size = EVEN(node_size + sizeof(pgno_t));
-      if ((intptr_t)node_size > room)
-        goto full;
-      if ((rc = mdbx_page_new(mc, P_OVERFLOW, ovpages, &ofp)))
-        return rc;
-      mdbx_debug("allocated overflow page %" PRIaPGNO, ofp->mp_pgno);
-      flags |= F_BIGDATA;
-      goto update;
-    } else {
-      node_size += data->iov_len;
-    }
-  }
-  node_size = EVEN(node_size);
-  if (unlikely((intptr_t)node_size > room))
-    goto full;
-
-update:
-  /* Move higher pointers up one slot. */
-  for (i = NUMKEYS(mp); i > indx; i--)
-    mp->mp_ptrs[i] = mp->mp_ptrs[i - 1];
-
-  /* Adjust free space offsets. */
-  size_t ofs = mp->mp_upper - node_size;
-  mdbx_cassert(mc, ofs >= mp->mp_lower + sizeof(indx_t));
-  mdbx_cassert(mc, ofs <= UINT16_MAX);
-  mp->mp_ptrs[indx] = (uint16_t)ofs;
-  mp->mp_upper = (uint16_t)ofs;
-  mp->mp_lower += sizeof(indx_t);
-
-  /* Write the node data. */
-  node = NODEPTR(mp, indx);
-  node->mn_ksize = (key == NULL) ? 0 : (uint16_t)key->iov_len;
-  node->mn_flags = (uint16_t)flags;
-  if (IS_LEAF(mp))
-    SETDSZ(node, data->iov_len);
-  else
-    SETPGNO(node, pgno);
-
-  if (key)
-    memcpy(NODEKEY(node), key->iov_base, key->iov_len);
-
-  if (IS_LEAF(mp)) {
-    ndata = NODEDATA(node);
-    if (likely(ofp == NULL)) {
-      if (unlikely(F_ISSET(flags, F_BIGDATA)))
-        memcpy(ndata, data->iov_base, sizeof(pgno_t));
-      else if (F_ISSET(flags, MDBX_RESERVE))
-        data->iov_base = ndata;
-      else if (likely(ndata != data->iov_base))
-        memcpy(ndata, data->iov_base, data->iov_len);
-    } else {
-      memcpy(ndata, &ofp->mp_pgno, sizeof(pgno_t));
-      ndata = PAGEDATA(ofp);
-      if (F_ISSET(flags, MDBX_RESERVE))
-        data->iov_base = ndata;
-      else if (likely(ndata != data->iov_base))
-        memcpy(ndata, data->iov_base, data->iov_len);
-    }
-  }
-
-  return MDBX_SUCCESS;
-
-full:
-  mdbx_debug("not enough room in page %" PRIaPGNO ", got %u ptrs", mp->mp_pgno,
-             NUMKEYS(mp));
-  mdbx_debug("upper-lower = %u - %u = %" PRIiPTR, mp->mp_upper, mp->mp_lower,
-             room);
-  mdbx_debug("node size = %" PRIuPTR, node_size);
-  mc->mc_txn->mt_flags |= MDBX_TXN_ERROR;
-  return MDBX_PAGE_FULL;
-}
-#endif
-
 /* Delete the specified node from a page.
  * [in] mc Cursor pointing to the node to delete.
  * [in] ksize The size of a node. Only used if the page is
@@ -11751,6 +11686,20 @@ int mdbx_dbi_open_ex(MDBX_txn *txn, const char *table_name, unsigned user_flags,
   if (unlikely(!txn || !dbi || (user_flags & ~VALID_FLAGS) != 0))
     return MDBX_EINVAL;
 
+  switch (user_flags &
+          (MDBX_INTEGERDUP | MDBX_DUPFIXED | MDBX_DUPSORT | MDBX_REVERSEDUP)) {
+  default:
+    return MDBX_EINVAL;
+  case MDBX_DUPSORT:
+  case MDBX_DUPSORT | MDBX_REVERSEDUP:
+  case MDBX_DUPSORT | MDBX_DUPFIXED:
+  case MDBX_DUPSORT | MDBX_DUPFIXED | MDBX_REVERSEDUP:
+  case MDBX_DUPSORT | MDBX_DUPFIXED | MDBX_INTEGERDUP:
+  case MDBX_DUPSORT | MDBX_DUPFIXED | MDBX_INTEGERDUP | MDBX_REVERSEDUP:
+  case 0:
+    break;
+  }
+
   if (unlikely(txn->mt_signature != MDBX_MT_SIGNATURE))
     return MDBX_EBADSIGN;
 
@@ -12983,7 +12932,7 @@ int mdbx_replace(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *new_data,
     rc = mdbx_cursor_get(&cx.outer, &present_key, &present_data, MDBX_SET_KEY);
     if (unlikely(rc != MDBX_SUCCESS)) {
       old_data->iov_base = NULL;
-      old_data->iov_len = rc;
+      old_data->iov_len = 0;
       if (rc != MDBX_NOTFOUND || (flags & MDBX_CURRENT))
         goto bailout;
     } else if (flags & MDBX_NOOVERWRITE) {
diff --git a/libs/libmdbx/src/test/gc.sh b/libs/libmdbx/src/test/gc.sh
index bddd92af24..0625518a4f 100644
--- a/libs/libmdbx/src/test/gc.sh
+++ b/libs/libmdbx/src/test/gc.sh
@@ -32,31 +32,31 @@ function probe {
 
 caption="Failfast #1" probe \
 	--pagesize=min --size=6G --table=+data.dups --keylen.min=min --keylen.max=max --datalen.min=min --datalen.max=max \
-	--nops=99999 --batch.write=9 --mode=-writemap,-coalesce,+lifo --keygen.seed=248240655 --hill
+	--nops=99999 --batch.write=9 --mode=-writemap,-coalesce,+lifo --keygen.seed=248240655 basic
 
 caption="Failfast #2" probe \
 	--pagesize=min --size=6G --table=-data.dups --keylen.min=min --keylen.max=max --datalen.min=min --datalen.max=1111 \
-	--nops=999999 --batch.write=999 --mode=+writemap,+coalesce,+lifo --keygen.seed=259083046 --hill
+	--nops=999999 --batch.write=999 --mode=+writemap,+coalesce,+lifo --keygen.seed=259083046 basic
 
 caption="Failfast #3" probe \
 	--pagesize=min --size=6G --table=-data.dups --keylen.min=min --keylen.max=max --datalen.min=min --datalen.max=1111 \
-	--nops=999999 --batch.write=999 --mode=+writemap,+coalesce,+lifo --keygen.seed=522365681 --hill
+	--nops=999999 --batch.write=999 --mode=+writemap,+coalesce,+lifo --keygen.seed=522365681 basic
 
 caption="Failfast #4" probe \
 	--pagesize=min --size=6G --table=-data.dups --keylen.min=min --keylen.max=max --datalen.min=min --datalen.max=1111 \
-	--nops=999999 --batch.write=9999 --mode=-writemap,+coalesce,+lifo --keygen.seed=866083781 --hill
+	--nops=999999 --batch.write=9999 --mode=-writemap,+coalesce,+lifo --keygen.seed=866083781 basic
 
 caption="Failfast #5" probe \
 	--pagesize=min --size=6G --table=-data.dups --keylen.min=min --keylen.max=max --datalen.min=min --datalen.max=1111 \
-	--nops=999999 --batch.write=999 --mode=+writemap,-coalesce,+lifo --keygen.seed=246539192 --hill
+	--nops=999999 --batch.write=999 --mode=+writemap,-coalesce,+lifo --keygen.seed=246539192 basic
 
 caption="Failfast #6" probe \
 	--pagesize=min --size=6G --table=-data.dups --keylen.min=min --keylen.max=max --datalen.min=min --datalen.max=1111 \
-	--nops=999999 --batch.write=999 --mode=+writemap,+coalesce,+lifo --keygen.seed=540406278 --hill
+	--nops=999999 --batch.write=999 --mode=+writemap,+coalesce,+lifo --keygen.seed=540406278 basic
 
 caption="Failfast #7" probe \
 	--pagesize=min --size=6G --table=+data.dups --keylen.min=min --keylen.max=max --datalen.min=min --datalen.max=max \
-	--nops=999999 --batch.write=999 --mode=-writemap,+coalesce,+lifo --keygen.seed=619798690 --hill
+	--nops=999999 --batch.write=999 --mode=-writemap,+coalesce,+lifo --keygen.seed=619798690 basic
 
 count=0
 for nops in {2..7}; do
@@ -65,14 +65,26 @@ for nops in {2..7}; do
 		for ((rep=0; rep++ < loops; )); do
 			for ((bits=2**${#options[@]}; --bits >= 0; )); do
 				seed=$(date +%N)
+				caption="Probe #$((++count)) int-key,w/o-dups, repeat ${rep} of ${loops}" probe \
+					--pagesize=min --size=6G --table=+key.integer,-data.dups --keylen.min=min --keylen.max=max --datalen.min=min --datalen.max=1111 \
+					--nops=$( rep9 $nops ) --batch.write=$( rep9 $wbatch ) --mode=$(bits2list options $bits) \
+					--keygen.seed=${seed} basic
+				caption="Probe #$((++count)) int-key,with-dups, repeat ${rep} of ${loops}" probe \
+					--pagesize=min --size=6G --table=+key.integer,+data.dups --keylen.min=min --keylen.max=max --datalen.min=min --datalen.max=max \
+					--nops=$( rep9 $nops ) --batch.write=$( rep9 $wbatch ) --mode=$(bits2list options $bits) \
+					--keygen.seed=${seed} basic
+				caption="Probe #$((++count)) int-key,int-data, repeat ${rep} of ${loops}" probe \
+					--pagesize=min --size=6G --table=+key.integer,+data.integer --keylen.min=min --keylen.max=max --datalen.min=min --datalen.max=max \
+					--nops=$( rep9 $nops ) --batch.write=$( rep9 $wbatch ) --mode=$(bits2list options $bits) \
+					--keygen.seed=${seed} basic
 				caption="Probe #$((++count)) w/o-dups, repeat ${rep} of ${loops}" probe \
 					--pagesize=min --size=6G --table=-data.dups --keylen.min=min --keylen.max=max --datalen.min=min --datalen.max=1111 \
 					--nops=$( rep9 $nops ) --batch.write=$( rep9 $wbatch ) --mode=$(bits2list options $bits) \
-					--keygen.seed=${seed} --hill
+					--keygen.seed=${seed} basic
 				caption="Probe #$((++count)) with-dups, repeat ${rep} of ${loops}" probe \
 					--pagesize=min --size=6G --table=+data.dups --keylen.min=min --keylen.max=max --datalen.min=min --datalen.max=max \
 					--nops=$( rep9 $nops ) --batch.write=$( rep9 $wbatch ) --mode=$(bits2list options $bits) \
-					--keygen.seed=${seed} --hill
+					--keygen.seed=${seed} basic
 			done
 		done
 	done
diff --git a/libs/libmdbx/src/test/hill.cc b/libs/libmdbx/src/test/hill.cc
index 0193c4f2f5..10cb308942 100644
--- a/libs/libmdbx/src/test/hill.cc
+++ b/libs/libmdbx/src/test/hill.cc
@@ -53,7 +53,7 @@ bool testcase_hill::run() {
    */
 
   /* TODO: работа в несколько потоков */
-  keyvalue_maker.setup(config.params, 0 /* thread_number */);
+  keyvalue_maker.setup(config.params, config.actor_id, 0 /* thread_number */);
 
   keygen::buffer a_key = keygen::alloc(config.params.keylen_max);
   keygen::buffer a_data_0 = keygen::alloc(config.params.datalen_max);
@@ -114,6 +114,7 @@ bool testcase_hill::run() {
     log_trace("uphill: update-a (age %" PRIu64 "->0) %" PRIu64, age_shift,
               a_serial);
     generate_pair(a_serial, a_key, a_data_0, 0);
+    checkdata("uphill: update-a", dbi, a_key->value, a_data_1->value);
     rc = mdbx_replace(txn_guard.get(), dbi, &a_key->value, &a_data_0->value,
                       &a_data_1->value, update_flags);
     if (unlikely(rc != MDBX_SUCCESS))
@@ -126,6 +127,7 @@ bool testcase_hill::run() {
 
     // удаляем вторую запись
     log_trace("uphill: delete-b %" PRIu64, b_serial);
+    checkdata("uphill: delete-b", dbi, b_key->value, b_data->value);
     rc = mdbx_del(txn_guard.get(), dbi, &b_key->value, &b_data->value);
     if (unlikely(rc != MDBX_SUCCESS))
       failure_perror("mdbx_del(b)", rc);
@@ -158,6 +160,7 @@ bool testcase_hill::run() {
               a_serial);
     generate_pair(a_serial, a_key, a_data_0, 0);
     generate_pair(a_serial, a_key, a_data_1, age_shift);
+    checkdata("downhill: update-a", dbi, a_key->value, a_data_0->value);
     int rc = mdbx_replace(txn_guard.get(), dbi, &a_key->value, &a_data_1->value,
                           &a_data_0->value, update_flags);
     if (unlikely(rc != MDBX_SUCCESS))
@@ -184,6 +187,7 @@ bool testcase_hill::run() {
     // удаляем первую запись
     log_trace("downhill: delete-a (age %" PRIu64 ") %" PRIu64, age_shift,
               a_serial);
+    checkdata("downhill: delete-a", dbi, a_key->value, a_data_1->value);
     rc = mdbx_del(txn_guard.get(), dbi, &a_key->value, &a_data_1->value);
     if (unlikely(rc != MDBX_SUCCESS))
       failure_perror("mdbx_del(a)", rc);
@@ -195,6 +199,7 @@ bool testcase_hill::run() {
 
     // удаляем вторую запись
     log_trace("downhill: delete-b %" PRIu64, b_serial);
+    checkdata("downhill: delete-b", dbi, b_key->value, b_data->value);
     rc = mdbx_del(txn_guard.get(), dbi, &b_key->value, &b_data->value);
     if (unlikely(rc != MDBX_SUCCESS))
       failure_perror("mdbx_del(b)", rc);
diff --git a/libs/libmdbx/src/test/jitter.cc b/libs/libmdbx/src/test/jitter.cc
index e7faf2a3f9..2551400443 100644
--- a/libs/libmdbx/src/test/jitter.cc
+++ b/libs/libmdbx/src/test/jitter.cc
@@ -58,7 +58,11 @@ bool testcase_jitter::run() {
 
     jitter_delay();
     db_close();
-    report(1);
+
+    /* just 'align' nops with other tests with batching */
+    const auto batching =
+        std::max(config.params.batch_read, config.params.batch_write);
+    report(std::max(1u, batching / 2));
   }
   return true;
 }
diff --git a/libs/libmdbx/src/test/keygen.cc b/libs/libmdbx/src/test/keygen.cc
index 0b68194dc1..c7a706065f 100644
--- a/libs/libmdbx/src/test/keygen.cc
+++ b/libs/libmdbx/src/test/keygen.cc
@@ -142,7 +142,7 @@ void __hot maker::pair(serial_t serial, const buffer &key, buffer &value,
   }
 }
 
-void maker::setup(const config::actor_params_pod &actor,
+void maker::setup(const config::actor_params_pod &actor, unsigned actor_id,
                   unsigned thread_number) {
   key_essentials.flags =
       actor.table_flags & (MDBX_INTEGERKEY | MDBX_REVERSEKEY | MDBX_DUPSORT);
@@ -161,7 +161,7 @@ void maker::setup(const config::actor_params_pod &actor,
   assert(thread_number < 2);
   (void)thread_number;
   mapping = actor.keygen;
-  salt = actor.keygen.seed * UINT64_C(14653293970879851569);
+  salt = (actor.keygen.seed + actor_id) * UINT64_C(14653293970879851569);
 
   // FIXME: TODO
   base = 0;
diff --git a/libs/libmdbx/src/test/keygen.h b/libs/libmdbx/src/test/keygen.h
index 449165ae9a..bbd97b29d1 100644
--- a/libs/libmdbx/src/test/keygen.h
+++ b/libs/libmdbx/src/test/keygen.h
@@ -119,7 +119,8 @@ public:
 
   void pair(serial_t serial, const buffer &key, buffer &value,
             serial_t value_age);
-  void setup(const config::actor_params_pod &actor, unsigned thread_number);
+  void setup(const config::actor_params_pod &actor, unsigned actor_id,
+             unsigned thread_number);
 
   bool increment(serial_t &serial, int delta);
 };
diff --git a/libs/libmdbx/src/test/main.cc b/libs/libmdbx/src/test/main.cc
index 7493ab75c3..3384311b3b 100644
--- a/libs/libmdbx/src/test/main.cc
+++ b/libs/libmdbx/src/test/main.cc
@@ -154,8 +154,14 @@ int main(int argc, char *const argv[]) {
                              config::mode_bits))
       continue;
     if (config::parse_option(argc, argv, narg, "table", params.table_flags,
-                             config::table_bits))
+                             config::table_bits)) {
+      if ((params.table_flags & MDBX_DUPFIXED) == 0)
+        params.table_flags &= ~MDBX_INTEGERDUP;
+      if ((params.table_flags & MDBX_DUPSORT) == 0)
+        params.table_flags &=
+            ~(MDBX_DUPFIXED | MDBX_REVERSEDUP | MDBX_INTEGERDUP);
       continue;
+    }
 
     if (config::parse_option(argc, argv, narg, "pagesize", params.pagesize,
                              mdbx_limits_pgsize_min(),
diff --git a/libs/libmdbx/src/test/osal-unix.cc b/libs/libmdbx/src/test/osal-unix.cc
index 8132e267ef..6661ae42c8 100644
--- a/libs/libmdbx/src/test/osal-unix.cc
+++ b/libs/libmdbx/src/test/osal-unix.cc
@@ -182,6 +182,9 @@ void osal_killall_actors(void) {
 }
 
 int osal_actor_poll(mdbx_pid_t &pid, unsigned timeout) {
+  struct timespec ts;
+  ts.tv_nsec = 0;
+  ts.tv_sec = timeout;
 retry:
   int status, options = WNOHANG;
 #ifdef WUNTRACED
@@ -209,9 +212,16 @@ retry:
   }
 
   if (pid == 0) {
-    if (timeout && sleep(timeout))
+    /* child still running */
+    if (ts.tv_sec == 0 && ts.tv_nsec == 0)
+      ts.tv_nsec = 1;
+    if (nanosleep(&ts, &ts) == 0) {
+      /* timeout and no signal fomr child */
+      pid = 0;
+      return 0;
+    }
+    if (errno == EINTR)
       goto retry;
-    return 0;
   }
 
   switch (errno) {
diff --git a/libs/libmdbx/src/test/test.cc b/libs/libmdbx/src/test/test.cc
index c28bbd221e..b9663c2a09 100644
--- a/libs/libmdbx/src/test/test.cc
+++ b/libs/libmdbx/src/test/test.cc
@@ -410,6 +410,16 @@ void testcase::db_table_close(MDBX_dbi handle) {
   log_trace("<< testcase::db_table_close");
 }
 
+void testcase::checkdata(const char *step, MDBX_dbi handle, MDBX_val key2check,
+                         MDBX_val expected_valued) {
+  MDBX_val actual_value = expected_valued;
+  int rc = mdbx_get2(txn_guard.get(), handle, &key2check, &actual_value);
+  if (unlikely(rc != MDBX_SUCCESS))
+    failure_perror(step, rc);
+  if (!is_samedata(&actual_value, &expected_valued))
+    failure("%s data mismatch", step);
+}
+
 //-----------------------------------------------------------------------------
 
 bool test_execute(const actor_config &config) {
diff --git a/libs/libmdbx/src/test/test.h b/libs/libmdbx/src/test/test.h
index ef1c4caa47..4b10a40fef 100644
--- a/libs/libmdbx/src/test/test.h
+++ b/libs/libmdbx/src/test/test.h
@@ -112,6 +112,8 @@ protected:
   void fetch_canary();
   void update_canary(uint64_t increment);
   void kick_progress(bool active) const;
+  void checkdata(const char *step, MDBX_dbi handle, MDBX_val key2check,
+                 MDBX_val expected_valued);
 
   MDBX_dbi db_table_open(bool create);
   void db_table_drop(MDBX_dbi handle);
diff --git a/libs/libmdbx/src/test/utils.cc b/libs/libmdbx/src/test/utils.cc
index 53a750e314..5a5290f057 100644
--- a/libs/libmdbx/src/test/utils.cc
+++ b/libs/libmdbx/src/test/utils.cc
@@ -91,6 +91,11 @@ bool hex2data(const char *hex_begin, const char *hex_end, void *ptr,
   return true;
 }
 
+bool is_samedata(const MDBX_val *a, const MDBX_val *b) {
+  return a->iov_len == b->iov_len &&
+         memcmp(a->iov_base, b->iov_base, a->iov_len) == 0;
+}
+
 //-----------------------------------------------------------------------------
 
 /* TODO: replace my 'libmera' from t1ha. */
diff --git a/libs/libmdbx/src/test/utils.h b/libs/libmdbx/src/test/utils.h
index 5d62909fd5..42d497e86e 100644
--- a/libs/libmdbx/src/test/utils.h
+++ b/libs/libmdbx/src/test/utils.h
@@ -317,7 +317,7 @@ struct simple_checksum {
 std::string data2hex(const void *ptr, size_t bytes, simple_checksum &checksum);
 bool hex2data(const char *hex_begin, const char *hex_end, void *ptr,
               size_t bytes, simple_checksum &checksum);
-
+bool is_samedata(const MDBX_val *a, const MDBX_val *b);
 std::string format(const char *fmt, ...);
 
 uint64_t entropy_ticks(void);