merge with libmdbx master

16 files changed, 338 insertions, 227 deletions

diff --git a/plugins/Dbx_mdbx/dbx_mdbx.vcxproj b/plugins/Dbx_mdbx/dbx_mdbx.vcxproj
index 0ef93cb590..4cc04efd5c 100644
--- a/plugins/Dbx_mdbx/dbx_mdbx.vcxproj
+++ b/plugins/Dbx_mdbx/dbx_mdbx.vcxproj
@@ -21,6 +21,7 @@
   <PropertyGroup Label="Globals">

     <ProjectName>Dbx_mdbx</ProjectName>

     <ProjectGuid>{E0ACDEA0-0AC9-4431-8CA3-6B0CCACB2E18}</ProjectGuid>

+    <WindowsTargetPlatformVersion>8.1</WindowsTargetPlatformVersion>

   </PropertyGroup>

   <ImportGroup Label="PropertySheets">

     <Import Project="$(ProjectDir)..\..\build\vc.common\plugin.props" />

diff --git a/plugins/Dbx_mdbx/src/dbintf.cpp b/plugins/Dbx_mdbx/src/dbintf.cpp
index cb663276c6..86d909a3bd 100644
--- a/plugins/Dbx_mdbx/src/dbintf.cpp
+++ b/plugins/Dbx_mdbx/src/dbintf.cpp
@@ -208,7 +208,7 @@ BOOL CDbxMDBX::Backup(const wchar_t *pwszPath)
 		return 1;

 	}

 

-	int res = mdbx_env_copy2fd(m_env, pFile, 0);

+	int res = mdbx_env_copy2fd(m_env, pFile, MDBX_CP_COMPACT);

 	CloseHandle(pFile);

 	if (res == MDBX_SUCCESS)

 		return 0;

diff --git a/plugins/Dbx_mdbx/src/libmdbx/.circleci/config.yml b/plugins/Dbx_mdbx/src/libmdbx/.circleci/config.yml
new file mode 100644
index 0000000000..91e11a4bfe
--- /dev/null
+++ b/plugins/Dbx_mdbx/src/libmdbx/.circleci/config.yml
@@ -0,0 +1,20 @@
+version: 2
+jobs:
+  build:
+    docker:
+      - image: circleci/buildpack-deps:artful
+    environment:
+      - TESTDB: /tmp/test.db
+      - TESTLOG: /tmp/test.log
+    steps:
+      - checkout
+      - run: make all
+      - run: ulimit -c unlimited && make check
+      - run:
+          command: |
+            mkdir -p /tmp/artifacts
+            mv -t /tmp/artifacts $TESTLOG $TESTDB core.*
+          when: on_fail
+      - store_artifacts:
+          path: /tmp/artifacts
+          destination: test-artifacts
diff --git a/plugins/Dbx_mdbx/src/libmdbx/README.md b/plugins/Dbx_mdbx/src/libmdbx/README.md
index 1a046717ee..92b6542fa7 100644
--- a/plugins/Dbx_mdbx/src/libmdbx/README.md
+++ b/plugins/Dbx_mdbx/src/libmdbx/README.md
@@ -20,6 +20,8 @@ libmdbx
    6. [Asynchronous lazy data flushing](https://sites.fas.harvard.edu/~cs265/papers/kathuria-2008.pdf) to disk(s);
    7. etc...
 
+Don't miss [Java Native Interface](https://github.com/castortech/mdbxjni) by [Castor Technologies](https://castortech.com/).
+
 -----
 
 Nowadays MDBX intended for Linux, and support Windows (since
diff --git a/plugins/Dbx_mdbx/src/libmdbx/appveyor.yml b/plugins/Dbx_mdbx/src/libmdbx/appveyor.yml
index ce817b237f..d002453fdd 100644
--- a/plugins/Dbx_mdbx/src/libmdbx/appveyor.yml
+++ b/plugins/Dbx_mdbx/src/libmdbx/appveyor.yml
@@ -1,4 +1,4 @@
-version: 0.1.5.{build}
+version: 0.2.0.{build}
 
 environment:
   matrix:
diff --git a/plugins/Dbx_mdbx/src/libmdbx/circle.yml b/plugins/Dbx_mdbx/src/libmdbx/circle.yml
deleted file mode 100644
index 77da30e932..0000000000
--- a/plugins/Dbx_mdbx/src/libmdbx/circle.yml
+++ /dev/null
@@ -1,14 +0,0 @@
-machine:
-  timezone:
-    Europe/Moscow
-
-database:
-  override:
-
-compile:
-  override:
-    - make all
-
-test:
-  override:
-    - make check || mv test.log ${CIRCLE_ARTIFACTS}/
diff --git a/plugins/Dbx_mdbx/src/libmdbx/mdbx.h b/plugins/Dbx_mdbx/src/libmdbx/mdbx.h
index 2f28623424..35faed8488 100644
--- a/plugins/Dbx_mdbx/src/libmdbx/mdbx.h
+++ b/plugins/Dbx_mdbx/src/libmdbx/mdbx.h
@@ -105,6 +105,7 @@ typedef DWORD mdbx_tid_t;
 #define MDBX_EIO ERROR_WRITE_FAULT
 #define MDBX_EPERM ERROR_INVALID_FUNCTION
 #define MDBX_EINTR ERROR_CANCELLED
+#define MDBX_ENOFILE ERROR_FILE_NOT_FOUND
 
 #else
 
@@ -125,6 +126,8 @@ typedef pthread_t mdbx_tid_t;
 #define MDBX_EIO EIO
 #define MDBX_EPERM EPERM
 #define MDBX_EINTR EINTR
+#define MDBX_ENOFILE ENOENT
+
 #endif
 
 #ifdef _MSC_VER
@@ -170,7 +173,7 @@ typedef pthread_t mdbx_tid_t;
 /*--------------------------------------------------------------------------*/
 
 #define MDBX_VERSION_MAJOR 0
-#define MDBX_VERSION_MINOR 1
+#define MDBX_VERSION_MINOR 2
 
 #if defined(LIBMDBX_EXPORTS)
 #define LIBMDBX_API __dll_export
@@ -700,7 +703,8 @@ LIBMDBX_API int mdbx_env_open(MDBX_env *env, const char *path, unsigned flags,
  *      NOTE: Currently it fails if the environment has suffered a page leak.
  *
  * Returns A non-zero error value on failure and 0 on success. */
-LIBMDBX_API int mdbx_env_copy(MDBX_env *env, const char *path, unsigned flags);
+LIBMDBX_API int mdbx_env_copy(MDBX_env *env, const char *dest_path,
+                              unsigned flags);
 
 /* Copy an MDBX environment to the specified file descriptor,
  * with options.
@@ -1657,7 +1661,9 @@ typedef int MDBX_pgvisitor_func(uint64_t pgno, unsigned pgnumber, void *ctx,
 LIBMDBX_API int mdbx_env_pgwalk(MDBX_txn *txn, MDBX_pgvisitor_func *visitor,
                                 void *ctx);
 
-typedef struct mdbx_canary { uint64_t x, y, z, v; } mdbx_canary;
+typedef struct mdbx_canary {
+  uint64_t x, y, z, v;
+} mdbx_canary;
 
 LIBMDBX_API int mdbx_canary_put(MDBX_txn *txn, const mdbx_canary *canary);
 LIBMDBX_API int mdbx_canary_get(MDBX_txn *txn, mdbx_canary *canary);
diff --git a/plugins/Dbx_mdbx/src/libmdbx/src/bits.h b/plugins/Dbx_mdbx/src/libmdbx/src/bits.h
index f535d749de..955a583264 100644
--- a/plugins/Dbx_mdbx/src/libmdbx/src/bits.h
+++ b/plugins/Dbx_mdbx/src/libmdbx/src/bits.h
@@ -1,4 +1,4 @@
-/*
+/*
  * Copyright 2015-2018 Leonid Yuriev <leo@yuriev.ru>
  * and other libmdbx authors: please see AUTHORS file.
  * All rights reserved.
@@ -370,19 +370,19 @@ typedef struct MDBX_page {
 #define PAGEHDRSZ ((unsigned)offsetof(MDBX_page, mp_data))
 
 /* The maximum size of a database page.
-*
-* It is 64K, but value-PAGEHDRSZ must fit in MDBX_page.mp_upper.
-*
-* MDBX will use database pages < OS pages if needed.
-* That causes more I/O in write transactions: The OS must
-* know (read) the whole page before writing a partial page.
-*
-* Note that we don't currently support Huge pages. On Linux,
-* regular data files cannot use Huge pages, and in general
-* Huge pages aren't actually pageable. We rely on the OS
-* demand-pager to read our data and page it out when memory
-* pressure from other processes is high. So until OSs have
-* actual paging support for Huge pages, they're not viable. */
+ *
+ * It is 64K, but value-PAGEHDRSZ must fit in MDBX_page.mp_upper.
+ *
+ * MDBX will use database pages < OS pages if needed.
+ * That causes more I/O in write transactions: The OS must
+ * know (read) the whole page before writing a partial page.
+ *
+ * Note that we don't currently support Huge pages. On Linux,
+ * regular data files cannot use Huge pages, and in general
+ * Huge pages aren't actually pageable. We rely on the OS
+ * demand-pager to read our data and page it out when memory
+ * pressure from other processes is high. So until OSs have
+ * actual paging support for Huge pages, they're not viable. */
 #define MAX_PAGESIZE 0x10000u
 #define MIN_PAGESIZE 512u
 
@@ -411,7 +411,7 @@ typedef struct MDBX_lockinfo {
   volatile uint32_t mti_envmode;
 
 #ifdef MDBX_OSAL_LOCK
-  /* Mutex protecting write access to this table. */
+  /* Mutex protecting write-txn. */
   union {
     MDBX_OSAL_LOCK mti_wmutex;
     uint8_t pad_mti_wmutex[MDBX_OSAL_LOCK_SIZE % sizeof(size_t)];
@@ -736,14 +736,17 @@ struct MDBX_env {
   /* Max MDBX_lockinfo.mti_numreaders of interest to mdbx_env_close() */
   unsigned me_close_readers;
   mdbx_fastmutex_t me_dbi_lock;
-  MDBX_dbi me_numdbs;          /* number of DBs opened */
-  MDBX_dbi me_maxdbs;          /* size of the DB table */
-  mdbx_pid_t me_pid;           /* process ID of this env */
-  mdbx_thread_key_t me_txkey;  /* thread-key for readers */
-  char *me_path;               /* path to the DB files */
-  void *me_pbuf;               /* scratch area for DUPSORT put() */
-  MDBX_txn *me_txn;            /* current write transaction */
-  MDBX_txn *me_txn0;           /* prealloc'd write transaction */
+  MDBX_dbi me_numdbs;         /* number of DBs opened */
+  MDBX_dbi me_maxdbs;         /* size of the DB table */
+  mdbx_pid_t me_pid;          /* process ID of this env */
+  mdbx_thread_key_t me_txkey; /* thread-key for readers */
+  char *me_path;              /* path to the DB files */
+  void *me_pbuf;              /* scratch area for DUPSORT put() */
+  MDBX_txn *me_txn;           /* current write transaction */
+  MDBX_txn *me_txn0;          /* prealloc'd write transaction */
+#ifdef MDBX_OSAL_LOCK
+  MDBX_OSAL_LOCK *me_wmutex; /* write-txn mutex */
+#endif
   MDBX_dbx *me_dbxs;           /* array of static DB info */
   uint16_t *me_dbflags;        /* array of flags from MDBX_db.md_flags */
   unsigned *me_dbiseqs;        /* array of dbi sequence numbers */
@@ -788,6 +791,7 @@ struct MDBX_env {
   /* Workaround for LockFileEx and WriteFile multithread bug */
   CRITICAL_SECTION me_windowsbug_lock;
 #else
+  mdbx_fastmutex_t me_lckless_wmutex;
   mdbx_fastmutex_t me_remap_guard;
 #endif
 };
diff --git a/plugins/Dbx_mdbx/src/libmdbx/src/lck-posix.c b/plugins/Dbx_mdbx/src/libmdbx/src/lck-posix.c
index 532505e807..869b98c054 100644
--- a/plugins/Dbx_mdbx/src/libmdbx/src/lck-posix.c
+++ b/plugins/Dbx_mdbx/src/libmdbx/src/lck-posix.c
@@ -86,16 +86,19 @@ static __inline int mdbx_lck_shared(int lfd) {
 }
 
 int mdbx_lck_downgrade(MDBX_env *env, bool complete) {
+  assert(env->me_lfd != INVALID_HANDLE_VALUE);
   return complete ? mdbx_lck_shared(env->me_lfd) : MDBX_SUCCESS;
 }
 
 int mdbx_lck_upgrade(MDBX_env *env) { return mdbx_lck_exclusive(env->me_lfd); }
 
 int mdbx_rpid_set(MDBX_env *env) {
+  assert(env->me_lfd != INVALID_HANDLE_VALUE);
   return mdbx_lck_op(env->me_lfd, F_SETLK, F_WRLCK, env->me_pid, 1);
 }
 
 int mdbx_rpid_clear(MDBX_env *env) {
+  assert(env->me_lfd != INVALID_HANDLE_VALUE);
   return mdbx_lck_op(env->me_lfd, F_SETLKW, F_UNLCK, env->me_pid, 1);
 }
 
@@ -106,6 +109,7 @@ int mdbx_rpid_clear(MDBX_env *env) {
  *   MDBX_RESULT_FALSE, if pid is dead (lock acquired)
  *   or otherwise the errcode. */
 int mdbx_rpid_check(MDBX_env *env, mdbx_pid_t pid) {
+  assert(env->me_lfd != INVALID_HANDLE_VALUE);
   int rc = mdbx_lck_op(env->me_lfd, F_GETLK, F_WRLCK, pid, 1);
   if (rc == 0)
     return MDBX_RESULT_FALSE;
@@ -118,7 +122,7 @@ int mdbx_rpid_check(MDBX_env *env, mdbx_pid_t pid) {
 
 static int mdbx_mutex_failed(MDBX_env *env, pthread_mutex_t *mutex, int rc);
 
-int mdbx_lck_init(MDBX_env *env) {
+int __cold mdbx_lck_init(MDBX_env *env) {
   pthread_mutexattr_t ma;
   int rc = pthread_mutexattr_init(&ma);
   if (rc)
@@ -156,7 +160,7 @@ bailout:
   return rc;
 }
 
-void mdbx_lck_destroy(MDBX_env *env) {
+void __cold mdbx_lck_destroy(MDBX_env *env) {
   if (env->me_lfd != INVALID_HANDLE_VALUE) {
     /* try get exclusive access */
     if (env->me_lck && mdbx_lck_exclusive(env->me_lfd) == 0) {
@@ -166,7 +170,8 @@ void mdbx_lck_destroy(MDBX_env *env) {
         rc = pthread_mutex_destroy(&env->me_lck->mti_wmutex);
       assert(rc == 0);
       (void)rc;
-      /* lock would be released (by kernel) while the me_lfd will be closed */
+      /* file locks would be released (by kernel)
+       * while the me_lfd will be closed */
     }
   }
 }
@@ -209,21 +214,21 @@ void mdbx_rdt_unlock(MDBX_env *env) {
 
 int mdbx_txn_lock(MDBX_env *env, bool dontwait) {
   mdbx_trace(">>");
-  int rc = dontwait ? mdbx_robust_trylock(env, &env->me_lck->mti_wmutex)
-                    : mdbx_robust_lock(env, &env->me_lck->mti_wmutex);
+  int rc = dontwait ? mdbx_robust_trylock(env, env->me_wmutex)
+                    : mdbx_robust_lock(env, env->me_wmutex);
   mdbx_trace("<< rc %d", rc);
   return MDBX_IS_ERROR(rc) ? rc : MDBX_SUCCESS;
 }
 
 void mdbx_txn_unlock(MDBX_env *env) {
   mdbx_trace(">>");
-  int rc = mdbx_robust_unlock(env, &env->me_lck->mti_wmutex);
+  int rc = mdbx_robust_unlock(env, env->me_wmutex);
   mdbx_trace("<< rc %d", rc);
   if (unlikely(MDBX_IS_ERROR(rc)))
     mdbx_panic("%s() failed: errcode %d\n", mdbx_func_, rc);
 }
 
-static int internal_seize_lck(int lfd) {
+static int __cold internal_seize_lck(int lfd) {
   assert(lfd != INVALID_HANDLE_VALUE);
 
   /* try exclusive access */
@@ -249,17 +254,19 @@ static int internal_seize_lck(int lfd) {
   return rc;
 }
 
-int mdbx_lck_seize(MDBX_env *env) {
+int __cold mdbx_lck_seize(MDBX_env *env) {
   assert(env->me_fd != INVALID_HANDLE_VALUE);
 
   if (env->me_lfd == INVALID_HANDLE_VALUE) {
-    /* LY: without-lck mode (e.g. on read-only filesystem) */
-    int rc = mdbx_lck_op(env->me_fd, F_SETLK, F_RDLCK, 0, LCK_WHOLE);
+    /* LY: without-lck mode (e.g. exclusive or on read-only filesystem) */
+    int rc = mdbx_lck_op(env->me_fd, F_SETLK,
+                         (env->me_flags & MDBX_RDONLY) ? F_RDLCK : F_WRLCK, 0,
+                         LCK_WHOLE);
     if (rc != 0) {
       mdbx_error("%s(%s) failed: errcode %u", mdbx_func_, "without-lck", rc);
       return rc;
     }
-    return MDBX_RESULT_FALSE;
+    return MDBX_RESULT_TRUE;
   }
 
   if ((env->me_flags & MDBX_RDONLY) == 0) {
@@ -285,7 +292,7 @@ static int __cold mdbx_mutex_failed(MDBX_env *env, pthread_mutex_t *mutex,
   if (rc == EOWNERDEAD) {
     /* We own the mutex. Clean up after dead previous owner. */
 
-    int rlocked = (mutex == &env->me_lck->mti_rmutex);
+    int rlocked = (env->me_lck && mutex == &env->me_lck->mti_rmutex);
     rc = MDBX_SUCCESS;
     if (!rlocked) {
       if (unlikely(env->me_txn)) {
diff --git a/plugins/Dbx_mdbx/src/libmdbx/src/lck-windows.c b/plugins/Dbx_mdbx/src/libmdbx/src/lck-windows.c
index 6e53212b20..ab3fae57f8 100644
--- a/plugins/Dbx_mdbx/src/libmdbx/src/lck-windows.c
+++ b/plugins/Dbx_mdbx/src/libmdbx/src/lck-windows.c
@@ -1,4 +1,4 @@
-/*
+/*
  * Copyright 2015-2018 Leonid Yuriev <leo@yuriev.ru>
  * and other libmdbx authors: please see AUTHORS file.
  * All rights reserved.
@@ -133,8 +133,9 @@ int mdbx_txn_lock(MDBX_env *env, bool dontwait) {
   }
 
   if ((env->me_flags & MDBX_EXCLUSIVE) ||
-      flock(env->me_fd, dontwait ? (LCK_EXCLUSIVE | LCK_DONTWAIT)
-                                 : (LCK_EXCLUSIVE | LCK_WAITFOR),
+      flock(env->me_fd,
+            dontwait ? (LCK_EXCLUSIVE | LCK_DONTWAIT)
+                     : (LCK_EXCLUSIVE | LCK_WAITFOR),
             LCK_BODY))
     return MDBX_SUCCESS;
   int rc = GetLastError();
@@ -143,8 +144,8 @@ int mdbx_txn_lock(MDBX_env *env, bool dontwait) {
 }
 
 void mdbx_txn_unlock(MDBX_env *env) {
-  int rc = (env->me_flags & MDBX_EXCLUSIVE) ? TRUE
-                                            : funlock(env->me_fd, LCK_BODY);
+  int rc =
+      (env->me_flags & MDBX_EXCLUSIVE) ? TRUE : funlock(env->me_fd, LCK_BODY);
   LeaveCriticalSection(&env->me_windowsbug_lock);
   if (!rc)
     mdbx_panic("%s failed: errcode %u", mdbx_func_, GetLastError());
@@ -362,7 +363,7 @@ static int internal_seize_lck(HANDLE lfd) {
                "?-E(middle) >> S-E(locked)", rc);
 
   /* 8) now on S-E (locked) or still on ?-E (middle),
-  *    transite to S-? (used) or ?-? (free) */
+   *    transite to S-? (used) or ?-? (free) */
   if (!funlock(lfd, LCK_UPPER))
     mdbx_panic("%s(%s) failed: errcode %u", mdbx_func_,
                "X-E(locked/middle) >> X-?(used/free)", GetLastError());
diff --git a/plugins/Dbx_mdbx/src/libmdbx/src/mdbx.c b/plugins/Dbx_mdbx/src/libmdbx/src/mdbx.c
index ce3d7a52ce..e8bdc0085e 100644
--- a/plugins/Dbx_mdbx/src/libmdbx/src/mdbx.c
+++ b/plugins/Dbx_mdbx/src/libmdbx/src/mdbx.c
@@ -1,4 +1,4 @@
-/*
+/*
  * Copyright 2015-2018 Leonid Yuriev <leo@yuriev.ru>
  * and other libmdbx authors: please see AUTHORS file.
  * All rights reserved.
@@ -42,8 +42,8 @@
 int __hot mdbx_e2k_memcmp_bug_workaround(const void *s1, const void *s2,
                                          size_t n) {
   if (unlikely(n > 42
-               /* LY: align followed access if reasonable possible */ &&
-               (((uintptr_t)s1) & 7) != 0 &&
+               /* LY: align followed access if reasonable possible */
+               && (((uintptr_t)s1) & 7) != 0 &&
                (((uintptr_t)s1) & 7) == (((uintptr_t)s2) & 7))) {
     if (((uintptr_t)s1) & 1) {
       const int diff = *(uint8_t *)s1 - *(uint8_t *)s2;
@@ -1142,6 +1142,13 @@ const char *__cold mdbx_strerror(int errnum) {
     if (size)
       msg = buffer;
 #else
+    if (errnum < 0) {
+      static char buffer[32];
+      int rc = snprintf(buffer, sizeof(buffer) - 1, "unknown error %d", errnum);
+      assert(rc > 0);
+      (void)rc;
+      return buffer;
+    }
     msg = strerror(errnum);
 #endif
   }
@@ -1924,13 +1931,16 @@ static const char *mdbx_durable_str(const MDBX_meta *const meta) {
 static txnid_t mdbx_find_oldest(MDBX_txn *txn) {
   mdbx_tassert(txn, (txn->mt_flags & MDBX_RDONLY) == 0);
   const MDBX_env *env = txn->mt_env;
-  MDBX_lockinfo *const lck = env->me_lck;
-
   const txnid_t edge = mdbx_reclaiming_detent(env);
   mdbx_tassert(txn, edge <= txn->mt_txnid - 1);
+
+  MDBX_lockinfo *const lck = env->me_lck;
+  if (unlikely(env->me_lck == NULL /* exclusive mode */))
+    return edge;
+
   const txnid_t last_oldest = lck->mti_oldest;
   mdbx_tassert(txn, edge >= last_oldest);
-  if (last_oldest == edge)
+  if (likely(last_oldest == edge))
     return edge;
 
   const uint32_t nothing_changed = MDBX_STRING_TETRAD("None");
@@ -2041,6 +2051,11 @@ static int mdbx_mapresize(MDBX_env *env, const pgno_t size_pgno,
 
 bailout:
   if (rc == MDBX_SUCCESS) {
+#if defined(_WIN32) || defined(_WIN64)
+    assert(size_bytes == env->me_dxb_mmap.current);
+    assert(size_bytes <= env->me_dxb_mmap.filesize);
+    assert(limit_bytes == env->me_dxb_mmap.length);
+#endif
     env->me_dbgeo.now = size_bytes;
     env->me_dbgeo.upper = limit_bytes;
     if (env->me_txn) {
@@ -2722,9 +2737,6 @@ static int mdbx_env_sync_ex(MDBX_env *env, int force, int nonblock) {
   if (unlikely(flags & (MDBX_RDONLY | MDBX_FATAL_ERROR)))
     return MDBX_EACCESS;
 
-  if (unlikely(!env->me_lck))
-    return MDBX_PANIC;
-
   const bool outside_txn =
       (!env->me_txn0 || env->me_txn0->mt_owner != mdbx_thread_self());
 
@@ -4262,7 +4274,9 @@ int mdbx_txn_commit(MDBX_txn *txn) {
   }
   if (unlikely(rc != MDBX_SUCCESS))
     goto fail;
-  env->me_lck->mti_readers_refresh_flag = false;
+
+  if (likely(env->me_lck))
+    env->me_lck->mti_readers_refresh_flag = false;
   end_mode = MDBX_END_COMMITTED | MDBX_END_UPDATE | MDBX_END_EOTDONE;
 
 done:
@@ -4589,11 +4603,10 @@ static MDBX_page *__cold mdbx_init_metas(const MDBX_env *env, void *buffer) {
   MDBX_page *page1 = mdbx_meta_model(env, page0, 0);
   MDBX_page *page2 = mdbx_meta_model(env, page1, 1);
   mdbx_meta_model(env, page2, 2);
-  page2->mp_meta.mm_datasync_sign = MDBX_DATASIGN_WEAK;
   mdbx_assert(env, !mdbx_meta_eq(env, &page0->mp_meta, &page1->mp_meta));
   mdbx_assert(env, !mdbx_meta_eq(env, &page1->mp_meta, &page2->mp_meta));
   mdbx_assert(env, !mdbx_meta_eq(env, &page2->mp_meta, &page0->mp_meta));
-  return page1;
+  return page2;
 }
 
 static int mdbx_sync_locked(MDBX_env *env, unsigned flags,
@@ -4729,9 +4742,8 @@ static int mdbx_sync_locked(MDBX_env *env, unsigned flags,
   mdbx_assert(env, !mdbx_meta_eq(env, pending, meta2));
 
   mdbx_assert(env, ((env->me_flags ^ flags) & MDBX_WRITEMAP) == 0);
-  mdbx_ensure(env,
-              target == head ||
-                  mdbx_meta_txnid_stable(env, target) < pending->mm_txnid_a);
+  mdbx_ensure(env, target == head || mdbx_meta_txnid_stable(env, target) <
+                                         pending->mm_txnid_a);
   if (env->me_flags & MDBX_WRITEMAP) {
     mdbx_jitter4testing(true);
     if (likely(target != head)) {
@@ -4917,6 +4929,12 @@ int __cold mdbx_env_create(MDBX_env **penv) {
     mdbx_fastmutex_destroy(&env->me_dbi_lock);
     goto bailout;
   }
+  rc = mdbx_fastmutex_init(&env->me_lckless_wmutex);
+  if (unlikely(rc != MDBX_SUCCESS)) {
+    mdbx_fastmutex_destroy(&env->me_remap_guard);
+    mdbx_fastmutex_destroy(&env->me_dbi_lock);
+    goto bailout;
+  }
 #endif /* Windows */
 
   VALGRIND_CREATE_MEMPOOL(env, 0, 0);
@@ -5580,18 +5598,30 @@ static int __cold mdbx_setup_lck(MDBX_env *env, char *lck_pathname,
   assert(env->me_fd != INVALID_HANDLE_VALUE);
   assert(env->me_lfd == INVALID_HANDLE_VALUE);
 
-  uint32_t bExclusive = (env->me_flags & MDBX_EXCLUSIVE);
-  int err = mdbx_openfile(lck_pathname, O_RDWR | O_CREAT, mode, &env->me_lfd,
-                          (bExclusive) ? true : false);
+  const int open_flags =
+      (env->me_flags & MDBX_EXCLUSIVE) ? O_RDWR : O_RDWR | O_CREAT;
+  int err = mdbx_openfile(lck_pathname, open_flags, mode, &env->me_lfd,
+                          (env->me_flags & MDBX_EXCLUSIVE) ? true : false);
   if (err != MDBX_SUCCESS) {
-    if (err != MDBX_EROFS || (env->me_flags & MDBX_RDONLY) == 0)
+    if (!(err == MDBX_ENOFILE && (env->me_flags & MDBX_EXCLUSIVE)) &&
+        !(err == MDBX_EROFS && (env->me_flags & MDBX_RDONLY)))
       return err;
-    /* LY: without-lck mode (e.g. on read-only filesystem) */
+
+    /* LY: without-lck mode (e.g. exclusive or on read-only filesystem) */
     env->me_lfd = INVALID_HANDLE_VALUE;
+    const int rc = mdbx_lck_seize(env);
+    if (MDBX_IS_ERROR(rc))
+      return rc;
+
     env->me_oldest = &env->me_oldest_stub;
     env->me_maxreaders = UINT_MAX;
-    mdbx_debug("lck-setup: %s ", "lockless mode (readonly)");
-    return MDBX_SUCCESS;
+#ifdef MDBX_OSAL_LOCK
+    env->me_wmutex = &env->me_lckless_wmutex;
+#endif
+    mdbx_debug("lck-setup:%s%s%s", " lck-less",
+               (env->me_flags & MDBX_RDONLY) ? " readonly" : "",
+               (rc == MDBX_RESULT_TRUE) ? " exclusive" : " cooperative");
+    return rc;
   }
 
   /* Try to get exclusive lock. If we succeed, then
@@ -5600,8 +5630,9 @@ static int __cold mdbx_setup_lck(MDBX_env *env, char *lck_pathname,
   if (MDBX_IS_ERROR(rc))
     return rc;
 
-  mdbx_debug("lck-setup: %s ",
-             (rc == MDBX_RESULT_TRUE) ? "exclusive" : "shared");
+  mdbx_debug("lck-setup:%s%s%s", " with-lck",
+             (env->me_flags & MDBX_RDONLY) ? " readonly" : "",
+             (rc == MDBX_RESULT_TRUE) ? " exclusive" : " cooperative");
 
   uint64_t size;
   err = mdbx_filesize(env->me_lfd, &size);
@@ -5626,7 +5657,7 @@ static int __cold mdbx_setup_lck(MDBX_env *env, char *lck_pathname,
       size = wanna;
     }
   } else {
-    if (bExclusive)
+    if (env->me_flags & MDBX_EXCLUSIVE)
       return MDBX_BUSY;
     if (size > SSIZE_MAX || (size & (env->me_os_psize - 1)) ||
         size < env->me_os_psize) {
@@ -5643,8 +5674,7 @@ static int __cold mdbx_setup_lck(MDBX_env *env, char *lck_pathname,
   }
   env->me_maxreaders = (unsigned)maxreaders;
 
-  err = mdbx_mmap(MDBX_WRITEMAP | bExclusive, &env->me_lck_mmap, (size_t)size,
-                  (size_t)size);
+  err = mdbx_mmap(MDBX_WRITEMAP, &env->me_lck_mmap, (size_t)size, (size_t)size);
   if (unlikely(err != MDBX_SUCCESS))
     return err;
 
@@ -5693,6 +5723,9 @@ static int __cold mdbx_setup_lck(MDBX_env *env, char *lck_pathname,
 
   mdbx_assert(env, !MDBX_IS_ERROR(rc));
   env->me_oldest = &env->me_lck->mti_oldest;
+#ifdef MDBX_OSAL_LOCK
+  env->me_wmutex = &env->me_lck->mti_wmutex;
+#endif
   return rc;
 }
 
@@ -5798,52 +5831,54 @@ int __cold mdbx_env_open(MDBX_env *env, const char *path, unsigned flags,
   }
 
   mdbx_debug("opened dbenv %p", (void *)env);
-  const unsigned mode_flags =
-      MDBX_WRITEMAP | MDBX_NOSYNC | MDBX_NOMETASYNC | MDBX_MAPASYNC;
-  if (lck_rc == MDBX_RESULT_TRUE) {
-    env->me_lck->mti_envmode = env->me_flags & (mode_flags | MDBX_RDONLY);
-    if ((env->me_flags & MDBX_EXCLUSIVE) == 0) {
-      /* LY: downgrade lock only if exclusive access not requested.
-       *     in case exclusive==1, just leave value as is. */
-      rc = mdbx_lck_downgrade(env, true);
-      mdbx_debug("lck-downgrade-full: rc %i ", rc);
-    } else {
-      rc = mdbx_lck_downgrade(env, false);
-      mdbx_debug("lck-downgrade-partial: rc %i ", rc);
-    }
-    if (rc != MDBX_SUCCESS)
-      goto bailout;
-  } else {
-    if ((env->me_flags & MDBX_RDONLY) == 0) {
-      while (env->me_lck->mti_envmode == MDBX_RDONLY) {
-        if (mdbx_atomic_compare_and_swap32(&env->me_lck->mti_envmode,
-                                           MDBX_RDONLY,
-                                           env->me_flags & mode_flags))
-          break;
-        /* TODO: yield/relax cpu */
+  if (env->me_lck) {
+    const unsigned mode_flags =
+        MDBX_WRITEMAP | MDBX_NOSYNC | MDBX_NOMETASYNC | MDBX_MAPASYNC;
+    if (lck_rc == MDBX_RESULT_TRUE) {
+      env->me_lck->mti_envmode = env->me_flags & (mode_flags | MDBX_RDONLY);
+      if ((env->me_flags & MDBX_EXCLUSIVE) == 0) {
+        /* LY: downgrade lock only if exclusive access not requested.
+         *     in case exclusive==1, just leave value as is. */
+        rc = mdbx_lck_downgrade(env, true);
+        mdbx_debug("lck-downgrade-full: rc %i ", rc);
+      } else {
+        rc = mdbx_lck_downgrade(env, false);
+        mdbx_debug("lck-downgrade-partial: rc %i ", rc);
       }
-      if ((env->me_lck->mti_envmode ^ env->me_flags) & mode_flags) {
-        mdbx_error("current mode/flags incompatible with requested");
-        rc = MDBX_INCOMPATIBLE;
+      if (rc != MDBX_SUCCESS)
         goto bailout;
+    } else {
+      if ((env->me_flags & MDBX_RDONLY) == 0) {
+        while (env->me_lck->mti_envmode == MDBX_RDONLY) {
+          if (mdbx_atomic_compare_and_swap32(&env->me_lck->mti_envmode,
+                                             MDBX_RDONLY,
+                                             env->me_flags & mode_flags))
+            break;
+          /* TODO: yield/relax cpu */
+        }
+        if ((env->me_lck->mti_envmode ^ env->me_flags) & mode_flags) {
+          mdbx_error("current mode/flags incompatible with requested");
+          rc = MDBX_INCOMPATIBLE;
+          goto bailout;
+        }
       }
     }
-  }
 
-  if (env->me_lck && (env->me_flags & MDBX_NOTLS) == 0) {
-    rc = mdbx_rthc_alloc(&env->me_txkey, &env->me_lck->mti_readers[0],
-                         &env->me_lck->mti_readers[env->me_maxreaders]);
-    if (unlikely(rc != MDBX_SUCCESS))
-      goto bailout;
-    env->me_flags |= MDBX_ENV_TXKEY;
+    if ((env->me_flags & MDBX_NOTLS) == 0) {
+      rc = mdbx_rthc_alloc(&env->me_txkey, &env->me_lck->mti_readers[0],
+                           &env->me_lck->mti_readers[env->me_maxreaders]);
+      if (unlikely(rc != MDBX_SUCCESS))
+        goto bailout;
+      env->me_flags |= MDBX_ENV_TXKEY;
+    }
   }
 
   if ((flags & MDBX_RDONLY) == 0) {
     MDBX_txn *txn;
     int tsize = sizeof(MDBX_txn),
-        size = tsize +
-               env->me_maxdbs * (sizeof(MDBX_db) + sizeof(MDBX_cursor *) +
-                                 sizeof(unsigned) + 1);
+        size =
+            tsize + env->me_maxdbs * (sizeof(MDBX_db) + sizeof(MDBX_cursor *) +
+                                      sizeof(unsigned) + 1);
     if ((env->me_pbuf = calloc(1, env->me_psize)) && (txn = calloc(1, size))) {
       txn->mt_dbs = (MDBX_db *)((char *)txn + tsize);
       txn->mt_cursors = (MDBX_cursor **)(txn->mt_dbs + env->me_maxdbs);
@@ -5946,7 +5981,7 @@ int __cold mdbx_env_close_ex(MDBX_env *env, int dont_sync) {
   if (unlikely(env->me_signature != MDBX_ME_SIGNATURE))
     return MDBX_EBADSIGN;
 
-  if (env->me_lck && (env->me_flags & (MDBX_RDONLY | MDBX_FATAL_ERROR)) == 0) {
+  if ((env->me_flags & (MDBX_RDONLY | MDBX_FATAL_ERROR)) == 0) {
     if (env->me_txn0 && env->me_txn0->mt_owner &&
         env->me_txn0->mt_owner != mdbx_thread_self())
       return MDBX_BUSY;
@@ -5982,6 +6017,8 @@ int __cold mdbx_env_close_ex(MDBX_env *env, int dont_sync) {
   DeleteCriticalSection(&env->me_windowsbug_lock);
 #else
   mdbx_ensure(env,
+              mdbx_fastmutex_destroy(&env->me_lckless_wmutex) == MDBX_SUCCESS);
+  mdbx_ensure(env,
               mdbx_fastmutex_destroy(&env->me_remap_guard) == MDBX_SUCCESS);
 #endif /* Windows */
 
@@ -6087,7 +6124,7 @@ static int __hot mdbx_cmp_int_ua(const MDBX_val *a, const MDBX_val *b) {
     } while (pa != a->iov_base);
     return diff;
   }
-#else /* __BYTE_ORDER__ */
+#else  /* __BYTE_ORDER__ */
   return memcmp(a->iov_base, b->iov_base, a->iov_len);
 #endif /* __BYTE_ORDER__ */
 #endif /* UNALIGNED_OK */
@@ -6317,7 +6354,7 @@ static int mdbx_page_get(MDBX_cursor *mc, pgno_t pgno, MDBX_page **ret,
 
 mapped:
   p = pgno2page(env, pgno);
-/* TODO: check p->mp_validator here */
+  /* TODO: check p->mp_validator here */
 
 done:
   *ret = p;
@@ -7718,6 +7755,7 @@ int mdbx_cursor_put(MDBX_cursor *mc, MDBX_val *key, MDBX_val *data,
         offset = env->me_psize - (unsigned)olddata.iov_len;
         flags |= F_DUPDATA | F_SUBDATA;
         dummy.md_root = mp->mp_pgno;
+        dummy.md_seq = dummy.md_merkle = 0;
         sub_root = mp;
       }
       if (mp != fp) {
@@ -10040,9 +10078,8 @@ int mdbx_put(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data,
   if (unlikely(!TXN_DBI_EXIST(txn, dbi, DB_USRVALID)))
     return MDBX_EINVAL;
 
-  if (unlikely(flags &
-               ~(MDBX_NOOVERWRITE | MDBX_NODUPDATA | MDBX_RESERVE |
-                 MDBX_APPEND | MDBX_APPENDDUP | MDBX_CURRENT)))
+  if (unlikely(flags & ~(MDBX_NOOVERWRITE | MDBX_NODUPDATA | MDBX_RESERVE |
+                         MDBX_APPEND | MDBX_APPENDDUP | MDBX_CURRENT)))
     return MDBX_EINVAL;
 
   if (unlikely(txn->mt_flags & (MDBX_TXN_RDONLY | MDBX_TXN_BLOCKED)))
@@ -10086,8 +10123,8 @@ typedef struct mdbx_copy {
   MDBX_env *mc_env;
   MDBX_txn *mc_txn;
   mdbx_condmutex_t mc_condmutex;
-  char *mc_wbuf[2];
-  char *mc_over[2];
+  uint8_t *mc_wbuf[2];
+  uint8_t *mc_over[2];
   size_t mc_wlen[2];
   size_t mc_olen[2];
   mdbx_filehandle_t mc_fd;
@@ -10102,7 +10139,7 @@ typedef struct mdbx_copy {
 /* Dedicated writer thread for compacting copy. */
 static THREAD_RESULT __cold THREAD_CALL mdbx_env_copythr(void *arg) {
   mdbx_copy *my = arg;
-  char *ptr;
+  uint8_t *ptr;
   int toggle = 0;
   int rc;
 
@@ -10263,7 +10300,7 @@ static int __cold mdbx_env_cwalk(mdbx_copy *my, pgno_t *pg, int flags) {
             my->mc_wlen[toggle] += my->mc_env->me_psize;
             if (omp->mp_pages > 1) {
               my->mc_olen[toggle] = pgno2bytes(my->mc_env, omp->mp_pages - 1);
-              my->mc_over[toggle] = (char *)omp + my->mc_env->me_psize;
+              my->mc_over[toggle] = (uint8_t *)omp + my->mc_env->me_psize;
               rc = mdbx_env_cthr_toggle(my, 1);
               if (unlikely(rc != MDBX_SUCCESS))
                 goto done;
@@ -10343,23 +10380,26 @@ done:
 static int __cold mdbx_env_compact(MDBX_env *env, mdbx_filehandle_t fd) {
   MDBX_txn *txn = NULL;
   mdbx_thread_t thr;
-  mdbx_copy my;
-  memset(&my, 0, sizeof(my));
+  mdbx_copy ctx;
+  memset(&ctx, 0, sizeof(ctx));
 
-  int rc = mdbx_condmutex_init(&my.mc_condmutex);
+  int rc = mdbx_condmutex_init(&ctx.mc_condmutex);
   if (unlikely(rc != MDBX_SUCCESS))
     return rc;
-  rc = mdbx_memalign_alloc(env->me_os_psize, MDBX_WBUF * 2,
-                           (void **)&my.mc_wbuf[0]);
+
+  const size_t buffer_size = pgno2bytes(env, NUM_METAS) + MDBX_WBUF * 2;
+  uint8_t *buffer = NULL;
+  rc = mdbx_memalign_alloc(env->me_os_psize, buffer_size, (void **)&buffer);
   if (unlikely(rc != MDBX_SUCCESS))
     goto done;
 
-  memset(my.mc_wbuf[0], 0, MDBX_WBUF * 2);
-  my.mc_wbuf[1] = my.mc_wbuf[0] + MDBX_WBUF;
-  my.mc_next_pgno = NUM_METAS;
-  my.mc_env = env;
-  my.mc_fd = fd;
-  rc = mdbx_thread_create(&thr, mdbx_env_copythr, &my);
+  ctx.mc_wbuf[0] = buffer + pgno2bytes(env, NUM_METAS);
+  memset(ctx.mc_wbuf[0], 0, MDBX_WBUF * 2);
+  ctx.mc_wbuf[1] = ctx.mc_wbuf[0] + MDBX_WBUF;
+  ctx.mc_next_pgno = NUM_METAS;
+  ctx.mc_env = env;
+  ctx.mc_fd = fd;
+  rc = mdbx_thread_create(&thr, mdbx_env_copythr, &ctx);
   if (unlikely(rc != MDBX_SUCCESS))
     goto done;
 
@@ -10367,7 +10407,7 @@ static int __cold mdbx_env_compact(MDBX_env *env, mdbx_filehandle_t fd) {
   if (unlikely(rc != MDBX_SUCCESS))
     goto finish;
 
-  MDBX_page *meta = mdbx_init_metas(env, my.mc_wbuf[0]);
+  MDBX_page *const meta = mdbx_init_metas(env, buffer);
 
   /* Set metapage 1 with current main DB */
   pgno_t new_root, root = txn->mt_dbs[MAIN_DBI].md_root;
@@ -10409,25 +10449,38 @@ static int __cold mdbx_env_compact(MDBX_env *env, mdbx_filehandle_t fd) {
   /* update signature */
   meta->mp_meta.mm_datasync_sign = mdbx_meta_sign(&meta->mp_meta);
 
-  my.mc_wlen[0] = pgno2bytes(env, NUM_METAS);
-  my.mc_txn = txn;
-  rc = mdbx_env_cwalk(&my, &root, 0);
+  ctx.mc_wlen[0] = pgno2bytes(env, NUM_METAS);
+  ctx.mc_txn = txn;
+  rc = mdbx_env_cwalk(&ctx, &root, 0);
   if (rc == MDBX_SUCCESS && root != new_root) {
-    mdbx_error("unexpected root %" PRIaPGNO " (%" PRIaPGNO ")", root, new_root);
-    rc = MDBX_PROBLEM; /* page leak or corrupt DB */
+    if (root > new_root) {
+      mdbx_error("post-compactification root %" PRIaPGNO
+                 " GT expected %" PRIaPGNO " (source DB corrupted)",
+                 root, new_root);
+      rc = MDBX_CORRUPTED; /* page leak or corrupt DB */
+    } else {
+      mdbx_error("post-compactification root %" PRIaPGNO
+                 " LT expected %" PRIaPGNO " (page leak(s) in source DB)",
+                 root, new_root);
+      /* fixup and rewrite metas */
+      meta->mp_meta.mm_dbs[MAIN_DBI].md_root = root;
+      meta->mp_meta.mm_geo.next = meta->mp_meta.mm_geo.now = root + 1;
+      meta->mp_meta.mm_datasync_sign = mdbx_meta_sign(&meta->mp_meta);
+      rc = mdbx_pwrite(fd, buffer, pgno2bytes(env, NUM_METAS), 0);
+    }
   }
 
 finish:
   if (rc != MDBX_SUCCESS)
-    my.mc_error = rc;
-  mdbx_env_cthr_toggle(&my, 1 | MDBX_EOF);
+    ctx.mc_error = rc;
+  mdbx_env_cthr_toggle(&ctx, 1 | MDBX_EOF);
   rc = mdbx_thread_join(thr);
   mdbx_txn_abort(txn);
 
 done:
-  mdbx_memalign_free(my.mc_wbuf[0]);
-  mdbx_condmutex_destroy(&my.mc_condmutex);
-  return rc ? rc : my.mc_error;
+  mdbx_memalign_free(buffer);
+  mdbx_condmutex_destroy(&ctx.mc_condmutex);
+  return rc ? rc : ctx.mc_error;
 }
 
 /* Copy environment as-is. */
@@ -10482,25 +10535,25 @@ int __cold mdbx_env_copy2fd(MDBX_env *env, mdbx_filehandle_t fd,
   return mdbx_env_copy_asis(env, fd);
 }
 
-int __cold mdbx_env_copy(MDBX_env *env, const char *path, unsigned flags) {
-  char *lck_pathname;
+int __cold mdbx_env_copy(MDBX_env *env, const char *dest_path, unsigned flags) {
+  char *dxb_pathname;
   mdbx_filehandle_t newfd = INVALID_HANDLE_VALUE;
 
   if (env->me_flags & MDBX_NOSUBDIR) {
-    lck_pathname = (char *)path;
+    dxb_pathname = (char *)dest_path;
   } else {
-    size_t len = strlen(path);
+    size_t len = strlen(dest_path);
     len += sizeof(MDBX_DATANAME);
-    lck_pathname = malloc(len);
-    if (!lck_pathname)
+    dxb_pathname = malloc(len);
+    if (!dxb_pathname)
       return MDBX_ENOMEM;
-    sprintf(lck_pathname, "%s" MDBX_DATANAME, path);
+    sprintf(dxb_pathname, "%s" MDBX_DATANAME, dest_path);
   }
 
   /* The destination path must exist, but the destination file must not.
    * We don't want the OS to cache the writes, since the source data is
    * already in the OS cache. */
-  int rc = mdbx_openfile(lck_pathname, O_WRONLY | O_CREAT | O_EXCL, 0666,
+  int rc = mdbx_openfile(dxb_pathname, O_WRONLY | O_CREAT | O_EXCL, 0640,
                          &newfd, true);
   if (rc == MDBX_SUCCESS) {
     if (env->me_psize >= env->me_os_psize) {
@@ -10515,15 +10568,17 @@ int __cold mdbx_env_copy(MDBX_env *env, const char *path, unsigned flags) {
     rc = mdbx_env_copy2fd(env, newfd, flags);
   }
 
-  if (!(env->me_flags & MDBX_NOSUBDIR))
-    free(lck_pathname);
-
   if (newfd != INVALID_HANDLE_VALUE) {
     int err = mdbx_closefile(newfd);
     if (rc == MDBX_SUCCESS && err != rc)
       rc = err;
+    if (rc != MDBX_SUCCESS)
+      (void)mdbx_removefile(dxb_pathname);
   }
 
+  if (dxb_pathname != dest_path)
+    free(dxb_pathname);
+
   return rc;
 }
 
@@ -10682,9 +10737,9 @@ int __cold mdbx_env_info(MDBX_env *env, MDBX_envinfo *arg, size_t bytes) {
 }
 
 static MDBX_cmp_func *mdbx_default_keycmp(unsigned flags) {
-  return (flags & MDBX_REVERSEKEY) ? mdbx_cmp_memnr : (flags & MDBX_INTEGERKEY)
-                                                          ? mdbx_cmp_int_a2
-                                                          : mdbx_cmp_memn;
+  return (flags & MDBX_REVERSEKEY)
+             ? mdbx_cmp_memnr
+             : (flags & MDBX_INTEGERKEY) ? mdbx_cmp_int_a2 : mdbx_cmp_memn;
 }
 
 static MDBX_cmp_func *mdbx_default_datacmp(unsigned flags) {
@@ -11220,28 +11275,31 @@ int __cold mdbx_reader_list(MDBX_env *env, MDBX_msg_func *func, void *ctx) {
     return MDBX_EBADSIGN;
 
   const MDBX_lockinfo *const lck = env->me_lck;
-  const unsigned snap_nreaders = lck->mti_numreaders;
-  for (unsigned i = 0; i < snap_nreaders; i++) {
-    if (lck->mti_readers[i].mr_pid) {
-      const txnid_t txnid = lck->mti_readers[i].mr_txnid;
-      if (txnid == ~(txnid_t)0)
-        snprintf(buf, sizeof(buf), "%10" PRIuPTR " %" PRIxPTR " -\n",
-                 (uintptr_t)lck->mti_readers[i].mr_pid,
-                 (uintptr_t)lck->mti_readers[i].mr_tid);
-      else
-        snprintf(buf, sizeof(buf), "%10" PRIuPTR " %" PRIxPTR " %" PRIaTXN "\n",
-                 (uintptr_t)lck->mti_readers[i].mr_pid,
-                 (uintptr_t)lck->mti_readers[i].mr_tid, txnid);
-
-      if (first) {
-        first = 0;
-        rc = func("    pid     thread     txnid\n", ctx);
+  if (likely(lck)) {
+    const unsigned snap_nreaders = lck->mti_numreaders;
+    for (unsigned i = 0; i < snap_nreaders; i++) {
+      if (lck->mti_readers[i].mr_pid) {
+        const txnid_t txnid = lck->mti_readers[i].mr_txnid;
+        if (txnid == ~(txnid_t)0)
+          snprintf(buf, sizeof(buf), "%10" PRIuPTR " %" PRIxPTR " -\n",
+                   (uintptr_t)lck->mti_readers[i].mr_pid,
+                   (uintptr_t)lck->mti_readers[i].mr_tid);
+        else
+          snprintf(buf, sizeof(buf),
+                   "%10" PRIuPTR " %" PRIxPTR " %" PRIaTXN "\n",
+                   (uintptr_t)lck->mti_readers[i].mr_pid,
+                   (uintptr_t)lck->mti_readers[i].mr_tid, txnid);
+
+        if (first) {
+          first = 0;
+          rc = func("    pid     thread     txnid\n", ctx);
+          if (rc < 0)
+            break;
+        }
+        rc = func(buf, ctx);
         if (rc < 0)
           break;
       }
-      rc = func(buf, ctx);
-      if (rc < 0)
-        break;
     }
   }
   if (first)
@@ -11306,6 +11364,13 @@ int __cold mdbx_reader_check0(MDBX_env *env, int rdt_locked, int *dead) {
   }
 
   MDBX_lockinfo *const lck = env->me_lck;
+  if (unlikely(lck == NULL)) {
+    /* exclusive mode */
+    if (dead)
+      *dead = 0;
+    return MDBX_SUCCESS;
+  }
+
   const unsigned snap_nreaders = lck->mti_numreaders;
   mdbx_pid_t *pids = alloca((snap_nreaders + 1) * sizeof(mdbx_pid_t));
   pids[0] = 0;
@@ -11420,7 +11485,7 @@ static txnid_t __cold mdbx_oomkick(MDBX_env *env, const txnid_t laggard) {
     mdbx_assert(env, oldest < env->me_txn0->mt_txnid);
     mdbx_assert(env, oldest >= laggard);
     mdbx_assert(env, oldest >= env->me_oldest[0]);
-    if (oldest == laggard)
+    if (oldest == laggard || unlikely(env->me_lck == NULL /* exclusive mode */))
       return oldest;
 
     if (MDBX_IS_ERROR(mdbx_reader_check0(env, false, NULL)))
@@ -11874,9 +11939,8 @@ int mdbx_replace(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *new_data,
   if (unlikely(!TXN_DBI_EXIST(txn, dbi, DB_USRVALID)))
     return MDBX_EINVAL;
 
-  if (unlikely(flags &
-               ~(MDBX_NOOVERWRITE | MDBX_NODUPDATA | MDBX_RESERVE |
-                 MDBX_APPEND | MDBX_APPENDDUP | MDBX_CURRENT)))
+  if (unlikely(flags & ~(MDBX_NOOVERWRITE | MDBX_NODUPDATA | MDBX_RESERVE |
+                         MDBX_APPEND | MDBX_APPENDDUP | MDBX_CURRENT)))
     return MDBX_EINVAL;
 
   if (unlikely(txn->mt_flags & (MDBX_TXN_RDONLY | MDBX_TXN_BLOCKED)))
diff --git a/plugins/Dbx_mdbx/src/libmdbx/src/osal.c b/plugins/Dbx_mdbx/src/libmdbx/src/osal.c
index 56df979872..c2fced0b4a 100644
--- a/plugins/Dbx_mdbx/src/libmdbx/src/osal.c
+++ b/plugins/Dbx_mdbx/src/libmdbx/src/osal.c
@@ -1,4 +1,4 @@
-/* https://en.wikipedia.org/wiki/Operating_system_abstraction_layer */
+/* https://en.wikipedia.org/wiki/Operating_system_abstraction_layer */
 
 /*
  * Copyright 2015-2018 Leonid Yuriev <leo@yuriev.ru>
@@ -191,7 +191,7 @@ __cold void mdbx_panic(const char *fmt, ...) {
   abort();
 }
 
-  /*----------------------------------------------------------------------------*/
+/*----------------------------------------------------------------------------*/
 
 #ifndef mdbx_asprintf
 int mdbx_asprintf(char **strp, const char *fmt, ...) {
@@ -408,6 +408,13 @@ int mdbx_fastmutex_release(mdbx_fastmutex_t *fastmutex) {
 
 /*----------------------------------------------------------------------------*/
 
+int mdbx_removefile(const char *pathname) {
+#if defined(_WIN32) || defined(_WIN64)
+  return DeleteFileA(pathname) ? MDBX_SUCCESS : GetLastError();
+#else
+  return unlink(pathname) ? errno : MDBX_SUCCESS;
+#endif
+}
 int mdbx_openfile(const char *pathname, int flags, mode_t mode,
                   mdbx_filehandle_t *fd, bool exclusive) {
   *fd = INVALID_HANDLE_VALUE;
@@ -431,8 +438,7 @@ int mdbx_openfile(const char *pathname, int flags, mode_t mode,
     break;
   case O_RDWR:
     DesiredAccess = GENERIC_READ | GENERIC_WRITE;
-    ShareMode =
-        exclusive ? FILE_SHARE_READ : (FILE_SHARE_READ | FILE_SHARE_WRITE);
+    ShareMode = exclusive ? 0 : (FILE_SHARE_READ | FILE_SHARE_WRITE);
     break;
   }
 
@@ -856,13 +862,11 @@ int mdbx_mmap(int flags, mdbx_mmap_t *map, size_t size, size_t limit) {
   map->section = NULL;
   map->address = nullptr;
 
-  if (!(flags & MDBX_EXCLUSIVE)) {
-    NTSTATUS rc = mdbx_check4nonlocal(map->fd, flags);
-    if (rc != MDBX_SUCCESS)
-      return rc;
-  }
+  NTSTATUS rc = mdbx_check4nonlocal(map->fd, flags);
+  if (rc != MDBX_SUCCESS)
+    return rc;
 
-  NTSTATUS rc = mdbx_filesize(map->fd, &map->filesize);
+  rc = mdbx_filesize(map->fd, &map->filesize);
   if (rc != MDBX_SUCCESS)
     return rc;
   if ((flags & MDBX_RDONLY) == 0 && map->filesize != size) {
@@ -878,13 +882,13 @@ int mdbx_mmap(int flags, mdbx_mmap_t *map, size_t size, size_t limit) {
   rc = NtCreateSection(
       &map->section,
       /* DesiredAccess */
-          (flags & MDBX_WRITEMAP)
+      (flags & MDBX_WRITEMAP)
           ? SECTION_QUERY | SECTION_MAP_READ | SECTION_EXTEND_SIZE |
                 SECTION_MAP_WRITE
           : SECTION_QUERY | SECTION_MAP_READ | SECTION_EXTEND_SIZE,
       /* ObjectAttributes */ NULL, /* MaximumSize (InitialSize) */ &SectionSize,
       /* SectionPageProtection */
-          (flags & MDBX_RDONLY) ? PAGE_READONLY : PAGE_READWRITE,
+      (flags & MDBX_RDONLY) ? PAGE_READONLY : PAGE_READWRITE,
       /* AllocationAttributes */ SEC_RESERVE, map->fd);
   if (!NT_SUCCESS(rc))
     return ntstatus2errcode(rc);
@@ -898,7 +902,7 @@ int mdbx_mmap(int flags, mdbx_mmap_t *map, size_t size, size_t limit) {
       /* InheritDisposition */ ViewUnmap,
       /* AllocationType */ (flags & MDBX_RDONLY) ? 0 : MEM_RESERVE,
       /* Win32Protect */
-          (flags & MDBX_WRITEMAP) ? PAGE_READWRITE : PAGE_READONLY);
+      (flags & MDBX_WRITEMAP) ? PAGE_READWRITE : PAGE_READONLY);
   if (!NT_SUCCESS(rc)) {
     NtClose(map->section);
     map->section = 0;
@@ -933,11 +937,6 @@ int mdbx_munmap(mdbx_mmap_t *map) {
   if (!NT_SUCCESS(rc))
     ntstatus2errcode(rc);
 
-  if (map->filesize != map->current &&
-      mdbx_filesize(map->fd, &map->filesize) == MDBX_SUCCESS &&
-      map->filesize != map->current)
-    (void)mdbx_ftruncate(map->fd, map->current);
-
   map->length = 0;
   map->current = 0;
   map->address = nullptr;
@@ -963,8 +962,11 @@ int mdbx_mresize(int flags, mdbx_mmap_t *map, size_t size, size_t limit) {
     /* growth rw-section */
     SectionSize.QuadPart = size;
     status = NtExtendSection(map->section, &SectionSize);
-    if (NT_SUCCESS(status))
-      map->filesize = map->current = size;
+    if (NT_SUCCESS(status)) {
+      map->current = size;
+      if (map->filesize < size)
+        map->filesize = size;
+    }
     return ntstatus2errcode(status);
   }
 
@@ -1040,14 +1042,14 @@ retry_file_and_section:
   status = NtCreateSection(
       &map->section,
       /* DesiredAccess */
-          (flags & MDBX_WRITEMAP)
+      (flags & MDBX_WRITEMAP)
           ? SECTION_QUERY | SECTION_MAP_READ | SECTION_EXTEND_SIZE |
                 SECTION_MAP_WRITE
           : SECTION_QUERY | SECTION_MAP_READ | SECTION_EXTEND_SIZE,
       /* ObjectAttributes */ NULL,
       /* MaximumSize (InitialSize) */ &SectionSize,
       /* SectionPageProtection */
-          (flags & MDBX_RDONLY) ? PAGE_READONLY : PAGE_READWRITE,
+      (flags & MDBX_RDONLY) ? PAGE_READONLY : PAGE_READWRITE,
       /* AllocationAttributes */ SEC_RESERVE, map->fd);
 
   if (!NT_SUCCESS(status))
@@ -1072,7 +1074,7 @@ retry_mapview:;
       /* InheritDisposition */ ViewUnmap,
       /* AllocationType */ (flags & MDBX_RDONLY) ? 0 : MEM_RESERVE,
       /* Win32Protect */
-          (flags & MDBX_WRITEMAP) ? PAGE_READWRITE : PAGE_READONLY);
+      (flags & MDBX_WRITEMAP) ? PAGE_READWRITE : PAGE_READONLY);
 
   if (!NT_SUCCESS(status)) {
     if (status == /* STATUS_CONFLICTING_ADDRESSES */ 0xC0000018 &&
diff --git a/plugins/Dbx_mdbx/src/libmdbx/src/osal.h b/plugins/Dbx_mdbx/src/libmdbx/src/osal.h
index 41e53222d7..daa79064f9 100644
--- a/plugins/Dbx_mdbx/src/libmdbx/src/osal.h
+++ b/plugins/Dbx_mdbx/src/libmdbx/src/osal.h
@@ -1,4 +1,4 @@
-/* https://en.wikipedia.org/wiki/Operating_system_abstraction_layer */
+/* https://en.wikipedia.org/wiki/Operating_system_abstraction_layer */
 
 /*
  * Copyright 2015-2018 Leonid Yuriev <leo@yuriev.ru>
@@ -479,6 +479,7 @@ int mdbx_filesize(mdbx_filehandle_t fd, uint64_t *length);
 int mdbx_openfile(const char *pathname, int flags, mode_t mode,
                   mdbx_filehandle_t *fd, bool exclusive);
 int mdbx_closefile(mdbx_filehandle_t fd);
+int mdbx_removefile(const char *pathname);
 
 typedef struct mdbx_mmap_param {
   union {
diff --git a/plugins/Dbx_mdbx/src/libmdbx/src/tools/mdbx_chk.c b/plugins/Dbx_mdbx/src/libmdbx/src/tools/mdbx_chk.c
index 0fd23ae69f..51096c4053 100644
--- a/plugins/Dbx_mdbx/src/libmdbx/src/tools/mdbx_chk.c
+++ b/plugins/Dbx_mdbx/src/libmdbx/src/tools/mdbx_chk.c
@@ -73,8 +73,7 @@ struct {
 } walk;
 
 uint64_t total_unused_bytes;
-int exclusive = 2;
-int envflags = MDBX_RDONLY;
+int envflags = MDBX_RDONLY | MDBX_EXCLUSIVE;
 
 MDBX_env *env;
 MDBX_txn *txn;
@@ -706,7 +705,7 @@ void verbose_meta(int num, txnid_t txnid, uint64_t sign) {
     print(", stay");
 
   if (txnid > envinfo.mi_recent_txnid &&
-      (exclusive || (envflags & MDBX_RDONLY) == 0))
+      (envflags & (MDBX_EXCLUSIVE | MDBX_RDONLY)) == MDBX_EXCLUSIVE)
     print(", rolled-back %" PRIu64 " (%" PRIu64 " >>> %" PRIu64 ")",
           txnid - envinfo.mi_recent_txnid, txnid, envinfo.mi_recent_txnid);
   print("\n");
@@ -805,7 +804,7 @@ int main(int argc, char *argv[]) {
       envflags &= ~MDBX_RDONLY;
       break;
     case 'c':
-      exclusive = 0;
+      envflags &= ~MDBX_EXCLUSIVE;
       break;
     case 'd':
       dont_traversal = 1;
@@ -853,7 +852,19 @@ int main(int argc, char *argv[]) {
     goto bailout;
   }
 
-  rc = mdbx_env_open_ex(env, envname, envflags, 0664, &exclusive);
+  rc = mdbx_env_open(env, envname, envflags, 0664);
+  if ((envflags & MDBX_EXCLUSIVE) &&
+      (rc == MDBX_BUSY ||
+#if defined(_WIN32) || defined(_WIN64)
+       rc == ERROR_LOCK_VIOLATION || rc == ERROR_SHARING_VIOLATION
+#else
+       rc == EBUSY
+#endif
+       )) {
+    envflags &= ~MDBX_EXCLUSIVE;
+    rc = mdbx_env_open(env, envname, envflags, 0664);
+  }
+
   if (rc) {
     error("mdbx_env_open failed, error %d %s\n", rc, mdbx_strerror(rc));
     if (rc == MDBX_WANNA_RECOVERY && (envflags & MDBX_RDONLY))
@@ -861,7 +872,8 @@ int main(int argc, char *argv[]) {
     goto bailout;
   }
   if (verbose)
-    print(" - %s mode\n", exclusive ? "monopolistic" : "cooperative");
+    print(" - %s mode\n",
+          (envflags & MDBX_EXCLUSIVE) ? "monopolistic" : "cooperative");
 
   if ((envflags & MDBX_RDONLY) == 0) {
     rc = mdbx_txn_lock(env, false);
@@ -946,7 +958,7 @@ int main(int argc, char *argv[]) {
     ++problems_meta;
   }
 
-  if (exclusive > 1) {
+  if (envflags & MDBX_EXCLUSIVE) {
     if (verbose)
       print(" - performs full check recent-txn-id with meta-pages\n");
     problems_meta += check_meta_head(true);
@@ -1079,7 +1091,8 @@ int main(int argc, char *argv[]) {
   }
 
   if (problems_maindb == 0 && problems_freedb == 0) {
-    if (!dont_traversal && (exclusive || (envflags & MDBX_RDONLY) == 0)) {
+    if (!dont_traversal &&
+        (envflags & (MDBX_EXCLUSIVE | MDBX_RDONLY)) != MDBX_RDONLY) {
       if (walk.pgcount != lastpgno - freedb_pages) {
         error("used pages mismatch (%" PRIu64 " != %" PRIu64 ")\n",
               walk.pgcount, lastpgno - freedb_pages);
diff --git a/plugins/Dbx_mdbx/src/libmdbx/src/version.c b/plugins/Dbx_mdbx/src/libmdbx/src/version.c
index aeb15bed4b..dfb4a5724c 100644
--- a/plugins/Dbx_mdbx/src/libmdbx/src/version.c
+++ b/plugins/Dbx_mdbx/src/libmdbx/src/version.c
@@ -14,12 +14,12 @@
 
 #include "./bits.h"
 
-#if MDBX_VERSION_MAJOR != 0 || MDBX_VERSION_MINOR != 1
+#if MDBX_VERSION_MAJOR != 0 || MDBX_VERSION_MINOR != 2
 #error "API version mismatch!"
 #endif
 
-#define MDBX_VERSION_RELEASE 5
-#define MDBX_VERSION_REVISION 1
+#define MDBX_VERSION_RELEASE 0
+#define MDBX_VERSION_REVISION 2
 
 /*LIBMDBX_EXPORTS*/ const mdbx_version_info mdbx_version = {
     MDBX_VERSION_MAJOR,
diff --git a/plugins/Dbx_mdbx/src/libmdbx/test/base.h b/plugins/Dbx_mdbx/src/libmdbx/test/base.h
index bc82ff26c0..b23f776aa3 100644
--- a/plugins/Dbx_mdbx/src/libmdbx/test/base.h
+++ b/plugins/Dbx_mdbx/src/libmdbx/test/base.h
@@ -80,6 +80,10 @@
 #include "../src/defs.h"
 #include "../src/osal.h"
 
+#if !defined(__thread) && (defined(_MSC_VER) || defined(__DMC__))
+#define __thread __declspec(thread)
+#endif /* __thread */
+
 #ifdef _MSC_VER
 #pragma warning(pop)
 #pragma warning(disable : 4201) /* nonstandard extension used :                \