diff --git a/test/extra/txn.c++ b/test/extra/txn.c++
index 3a616015..e1abb1e6 100644
--- a/test/extra/txn.c++
+++ b/test/extra/txn.c++
@@ -1,4 +1,5 @@
 #include "mdbx.h++"
+#include MDBX_CONFIG_H
 
 #include <iostream>
 
@@ -25,267 +26,301 @@ static void logger_nofmt(MDBX_log_level_t loglevel, const char *function, int li
   fprintf(stdout, "%s:%u %s", function, line, msg);
 }
 
+bool case0(const mdbx::path &path) {
+  mdbx::env_managed::create_parameters createParameters;
+  createParameters.geometry.make_dynamic(21 * mdbx::env::geometry::MiB, 84 * mdbx::env::geometry::MiB);
+
+  mdbx::env::operate_parameters operateParameters(100, 10);
+  operateParameters.options.no_sticky_threads = false;
+  mdbx::env_managed env(path, createParameters, operateParameters);
+  auto txn = env.start_write(false);
+  /* mdbx::map_handle testHandle = */ txn.create_map("xyz", mdbx::key_mode::usual, mdbx::value_mode::single);
+  txn.commit();
+
+  //-------------------------------------
+  txn = env.start_write();
+  MDBX_txn *c_txn = txn;
+  int err = mdbx_txn_reset(txn);
+  assert(err == MDBX_EINVAL);
+  bool ok = err == MDBX_EINVAL;
+
+  err = mdbx_txn_break(txn);
+  assert(err == MDBX_SUCCESS);
+  ok = ok && err == MDBX_SUCCESS;
+
+  err = mdbx_txn_commit(txn);
+  assert(err == MDBX_RESULT_TRUE);
+  ok = ok && err == MDBX_RESULT_TRUE;
+
+  //-------------------------------------
+  err = mdbx_txn_begin(env, nullptr, MDBX_TXN_READWRITE, &c_txn);
+  assert(err == MDBX_SUCCESS);
+  ok = ok && err == MDBX_SUCCESS;
+  assert(c_txn == (const MDBX_txn *)txn);
+
+  err = mdbx_txn_break(txn);
+  assert(err == MDBX_SUCCESS);
+  ok = ok && err == MDBX_SUCCESS;
+
+  err = mdbx_txn_reset(txn);
+  assert(err == MDBX_EINVAL);
+  ok = ok && err == MDBX_EINVAL;
+
+  err = mdbx_txn_commit(txn);
+  assert(err == MDBX_RESULT_TRUE);
+  ok = ok && err == MDBX_RESULT_TRUE;
+
+  err = mdbx_txn_abort(c_txn);
+  assert(err == MDBX_BAD_TXN);
+  ok = ok && err == MDBX_BAD_TXN;
+  //-------------------------------------
+  err = mdbx_txn_begin(env, nullptr, MDBX_TXN_READWRITE, &c_txn);
+  assert(err == MDBX_SUCCESS);
+  ok = ok && err == MDBX_SUCCESS;
+  assert(c_txn == (const MDBX_txn *)txn);
+  txn.commit();
+
+  err = mdbx_txn_reset(c_txn);
+  assert(err == MDBX_BAD_TXN);
+  ok = ok && err == MDBX_BAD_TXN;
+  err = mdbx_txn_break(c_txn);
+  assert(err == MDBX_BAD_TXN);
+  ok = ok && err == MDBX_BAD_TXN;
+  err = mdbx_txn_abort(c_txn);
+  assert(err == MDBX_BAD_TXN);
+  ok = ok && err == MDBX_BAD_TXN;
+
+  //=====================================
+
+  txn = env.start_read();
+  err = mdbx_txn_begin(env, txn, MDBX_TXN_READWRITE, &c_txn);
+  assert(err == MDBX_BAD_TXN);
+  ok = ok && err == MDBX_BAD_TXN;
+  txn.make_broken();
+  err = mdbx_txn_begin(env, txn, MDBX_TXN_READWRITE, &c_txn);
+  assert(err == MDBX_BAD_TXN);
+  ok = ok && err == MDBX_BAD_TXN;
+  txn.reset_reading();
+  err = mdbx_txn_begin(env, txn, MDBX_TXN_READWRITE, &c_txn);
+  assert(err == MDBX_BAD_TXN);
+  ok = ok && err == MDBX_BAD_TXN;
+  txn.abort();
+
+  //-------------------------------------
+
+  txn = env.start_read();
+  txn.reset_reading();
+  txn.make_broken();
+  txn.abort();
+
+  //=====================================
+
+  std::latch s(1);
+  txn = env.start_read();
+  c_txn = txn;
+
+  std::thread t([&]() {
+    s.wait();
+#if MDBX_TXN_CHECKOWNER
+    err = mdbx_txn_reset(c_txn);
+    assert(err == MDBX_THREAD_MISMATCH);
+    ok = ok && err == MDBX_THREAD_MISMATCH;
+    err = mdbx_txn_break(c_txn);
+    assert(err == MDBX_THREAD_MISMATCH);
+    ok = ok && err == MDBX_THREAD_MISMATCH;
+    err = mdbx_txn_commit(c_txn);
+    assert(err == MDBX_THREAD_MISMATCH);
+    ok = ok && err == MDBX_THREAD_MISMATCH;
+    err = mdbx_txn_abort(c_txn);
+    assert(err == MDBX_THREAD_MISMATCH);
+    ok = ok && err == MDBX_THREAD_MISMATCH;
+#endif /* MDBX_TXN_CHECKOWNER */
+
+    err = mdbx_txn_begin(env, txn, MDBX_TXN_READWRITE, &c_txn);
+#if MDBX_TXN_CHECKOWNER
+    assert(err == MDBX_THREAD_MISMATCH);
+    ok = ok && err == MDBX_THREAD_MISMATCH;
+#else
+    assert(err == MDBX_BAD_TXN);
+    ok = ok && err == MDBX_BAD_TXN;
+#endif /* MDBX_TXN_CHECKOWNER */
+  });
+
+  s.count_down();
+  t.join();
+
+  return ok;
+}
+
+bool case1(const mdbx::path &path) {
+  mdbx::env::operate_parameters operateParameters(100, 10);
+  operateParameters.options.no_sticky_threads = true;
+  operateParameters.options.nested_write_transactions = true;
+  mdbx::env_managed env(path, operateParameters);
+
+  //-------------------------------------
+  auto txn = env.start_write();
+  MDBX_txn *c_txn = txn;
+  int err = mdbx_txn_reset(txn);
+  assert(err == MDBX_EINVAL);
+  bool ok = err == MDBX_EINVAL;
+
+  err = mdbx_txn_break(txn);
+  assert(err == MDBX_SUCCESS);
+  ok = ok && err == MDBX_SUCCESS;
+
+  err = mdbx_txn_commit(txn);
+  assert(err == MDBX_RESULT_TRUE);
+  ok = ok && err == MDBX_RESULT_TRUE;
+
+  //-------------------------------------
+  err = mdbx_txn_begin(env, nullptr, MDBX_TXN_READWRITE, &c_txn);
+  assert(err == MDBX_SUCCESS);
+  ok = ok && err == MDBX_SUCCESS;
+  assert(c_txn == (const MDBX_txn *)txn);
+
+  err = mdbx_txn_break(txn);
+  assert(err == MDBX_SUCCESS);
+  ok = ok && err == MDBX_SUCCESS;
+
+  err = mdbx_txn_reset(txn);
+  assert(err == MDBX_EINVAL);
+  ok = ok && err == MDBX_EINVAL;
+
+  err = mdbx_txn_commit(txn);
+  assert(err == MDBX_RESULT_TRUE);
+  ok = ok && err == MDBX_RESULT_TRUE;
+
+  err = mdbx_txn_abort(c_txn);
+  assert(err == MDBX_BAD_TXN);
+  ok = ok && err == MDBX_BAD_TXN;
+  //-------------------------------------
+  err = mdbx_txn_begin(env, nullptr, MDBX_TXN_READWRITE, &c_txn);
+  assert(err == MDBX_SUCCESS);
+  ok = ok && err == MDBX_SUCCESS;
+  assert(c_txn == (const MDBX_txn *)txn);
+  txn.commit();
+
+  err = mdbx_txn_reset(c_txn);
+  assert(err == MDBX_BAD_TXN);
+  ok = ok && err == MDBX_BAD_TXN;
+  err = mdbx_txn_break(c_txn);
+  assert(err == MDBX_BAD_TXN);
+  ok = ok && err == MDBX_BAD_TXN;
+  err = mdbx_txn_abort(c_txn);
+  assert(err == MDBX_BAD_TXN);
+  ok = ok && err == MDBX_BAD_TXN;
+
+  //=====================================
+
+  txn = env.start_read();
+  err = mdbx_txn_begin(env, txn, MDBX_TXN_READWRITE, &c_txn);
+  assert(err == MDBX_BAD_TXN);
+  ok = ok && err == MDBX_BAD_TXN;
+  txn.make_broken();
+  err = mdbx_txn_begin(env, txn, MDBX_TXN_READWRITE, &c_txn);
+  assert(err == MDBX_BAD_TXN);
+  ok = ok && err == MDBX_BAD_TXN;
+  txn.reset_reading();
+  err = mdbx_txn_begin(env, txn, MDBX_TXN_READWRITE, &c_txn);
+  assert(err == MDBX_BAD_TXN);
+  ok = ok && err == MDBX_BAD_TXN;
+  txn.abort();
+
+  //-------------------------------------
+
+  txn = env.start_read();
+  txn.reset_reading();
+  txn.make_broken();
+  txn.abort();
+
+  //=====================================
+
+  std::latch s1(1), s2(1), s3(1);
+  txn = env.start_read();
+  c_txn = txn;
+
+  std::thread t([&]() {
+    s1.wait();
+    err = mdbx_txn_break(c_txn);
+    assert(err == MDBX_SUCCESS);
+    ok = ok && err == MDBX_SUCCESS;
+    err = mdbx_txn_reset(c_txn);
+    assert(err == MDBX_SUCCESS);
+    ok = ok && err == MDBX_SUCCESS;
+    txn.renew_reading();
+    s2.count_down();
+
+    s3.wait();
+    err = mdbx_txn_begin(env, txn, MDBX_TXN_READWRITE, &c_txn);
+    assert(err == MDBX_SUCCESS);
+    ok = ok && err == MDBX_SUCCESS;
+    err = mdbx_txn_commit(c_txn);
+    assert(err == MDBX_SUCCESS);
+    ok = ok && err == MDBX_SUCCESS;
+    c_txn = txn;
+    err = mdbx_txn_commit(c_txn);
+    assert(err == MDBX_THREAD_MISMATCH);
+    ok = ok && err == MDBX_THREAD_MISMATCH;
+    err = mdbx_txn_abort(c_txn);
+    assert(err == MDBX_THREAD_MISMATCH);
+    ok = ok && err == MDBX_THREAD_MISMATCH;
+    err = mdbx_txn_break(c_txn);
+    assert(err == MDBX_SUCCESS);
+    ok = ok && err == MDBX_SUCCESS;
+    err = mdbx_txn_reset(c_txn);
+    assert(err == MDBX_EINVAL);
+    ok = ok && err == MDBX_EINVAL;
+  });
+
+  s1.count_down();
+  s2.wait();
+  txn.commit();
+  txn = env.start_write();
+  s3.count_down();
+
+  t.join();
+  txn.abort();
+
+  return ok;
+}
+
+bool case2(const mdbx::path &path, bool no_sticky_threads) {
+  mdbx::env::operate_parameters operateParameters(100, 10);
+  operateParameters.options.no_sticky_threads = no_sticky_threads;
+  mdbx::env_managed env(path, operateParameters);
+
+  std::latch s(1);
+  std::vector<std::thread> l;
+  for (size_t n = 0; n < 8; ++n)
+    l.push_back(std::thread([&]() {
+      s.wait();
+      for (size_t i = 0; i < 1000000; ++i) {
+        auto txn = env.start_read();
+        txn.abort();
+      }
+    }));
+
+  s.count_down();
+  for (auto &t : l)
+    t.join();
+
+  return true;
+}
+
 int main(int argc, const char *argv[]) {
   (void)argc;
   (void)argv;
-  bool ok = true;
-  int err;
 
   mdbx_setup_debug_nofmt(MDBX_LOG_VERBOSE, MDBX_DBG_ASSERT, logger_nofmt, log_buffer, sizeof(log_buffer));
 
   mdbx::path path = "test-txn";
   mdbx::env::remove(path);
-  mdbx::env::operate_parameters operateParameters(100, 10);
 
-  {
-    mdbx::env_managed::create_parameters createParameters;
-    createParameters.geometry.make_dynamic(21 * mdbx::env::geometry::MiB, 84 * mdbx::env::geometry::MiB);
-
-    operateParameters.options.no_sticky_threads = false;
-    mdbx::env_managed env(path, createParameters, operateParameters);
-    auto txn = env.start_write(false);
-    /* mdbx::map_handle testHandle = */ txn.create_map("xyz", mdbx::key_mode::usual, mdbx::value_mode::single);
-    txn.commit();
-
-    //-------------------------------------
-    txn = env.start_write();
-    MDBX_txn *c_txn = txn;
-    err = mdbx_txn_reset(txn);
-    assert(err == MDBX_EINVAL);
-    ok = ok && err == MDBX_EINVAL;
-
-    err = mdbx_txn_break(txn);
-    assert(err == MDBX_SUCCESS);
-    ok = ok && err == MDBX_SUCCESS;
-
-    err = mdbx_txn_commit(txn);
-    assert(err == MDBX_RESULT_TRUE);
-    ok = ok && err == MDBX_RESULT_TRUE;
-
-    //-------------------------------------
-    err = mdbx_txn_begin(env, nullptr, MDBX_TXN_READWRITE, &c_txn);
-    assert(err == MDBX_SUCCESS);
-    ok = ok && err == MDBX_SUCCESS;
-    assert(c_txn == (const MDBX_txn *)txn);
-
-    err = mdbx_txn_break(txn);
-    assert(err == MDBX_SUCCESS);
-    ok = ok && err == MDBX_SUCCESS;
-
-    err = mdbx_txn_reset(txn);
-    assert(err == MDBX_EINVAL);
-    ok = ok && err == MDBX_EINVAL;
-
-    err = mdbx_txn_commit(txn);
-    assert(err == MDBX_RESULT_TRUE);
-    ok = ok && err == MDBX_RESULT_TRUE;
-
-    err = mdbx_txn_abort(c_txn);
-    assert(err == MDBX_BAD_TXN);
-    ok = ok && err == MDBX_BAD_TXN;
-    //-------------------------------------
-    err = mdbx_txn_begin(env, nullptr, MDBX_TXN_READWRITE, &c_txn);
-    assert(err == MDBX_SUCCESS);
-    ok = ok && err == MDBX_SUCCESS;
-    assert(c_txn == (const MDBX_txn *)txn);
-    txn.commit();
-
-    err = mdbx_txn_reset(c_txn);
-    assert(err == MDBX_BAD_TXN);
-    ok = ok && err == MDBX_BAD_TXN;
-    err = mdbx_txn_break(c_txn);
-    assert(err == MDBX_BAD_TXN);
-    ok = ok && err == MDBX_BAD_TXN;
-    err = mdbx_txn_abort(c_txn);
-    assert(err == MDBX_BAD_TXN);
-    ok = ok && err == MDBX_BAD_TXN;
-
-    //=====================================
-
-    txn = env.start_read();
-    err = mdbx_txn_begin(env, txn, MDBX_TXN_READWRITE, &c_txn);
-    assert(err == MDBX_BAD_TXN);
-    ok = ok && err == MDBX_BAD_TXN;
-    txn.make_broken();
-    err = mdbx_txn_begin(env, txn, MDBX_TXN_READWRITE, &c_txn);
-    assert(err == MDBX_BAD_TXN);
-    ok = ok && err == MDBX_BAD_TXN;
-    txn.reset_reading();
-    err = mdbx_txn_begin(env, txn, MDBX_TXN_READWRITE, &c_txn);
-    assert(err == MDBX_BAD_TXN);
-    ok = ok && err == MDBX_BAD_TXN;
-    txn.abort();
-
-    //-------------------------------------
-
-    txn = env.start_read();
-    txn.reset_reading();
-    txn.make_broken();
-    txn.abort();
-
-    //=====================================
-
-    std::latch s(1);
-    txn = env.start_read();
-    c_txn = txn;
-
-    std::thread t([&]() {
-      s.wait();
-#if MDBX_TXN_CHECKOWNER
-      err = mdbx_txn_reset(c_txn);
-      assert(err == MDBX_THREAD_MISMATCH);
-      ok = ok && err == MDBX_THREAD_MISMATCH;
-      err = mdbx_txn_break(c_txn);
-      assert(err == MDBX_THREAD_MISMATCH);
-      ok = ok && err == MDBX_THREAD_MISMATCH;
-      err = mdbx_txn_commit(c_txn);
-      assert(err == MDBX_THREAD_MISMATCH);
-      ok = ok && err == MDBX_THREAD_MISMATCH;
-      err = mdbx_txn_abort(c_txn);
-      assert(err == MDBX_THREAD_MISMATCH);
-      ok = ok && err == MDBX_THREAD_MISMATCH;
-#endif /* MDBX_TXN_CHECKOWNER */
-      err = mdbx_txn_begin(env, txn, MDBX_TXN_READWRITE, &c_txn);
-      assert(err == MDBX_BAD_TXN);
-      ok = ok && err == MDBX_BAD_TXN;
-    });
-
-    s.count_down();
-    t.join();
-  }
-
-  //=====================================
-  //=====================================
-
-  {
-    operateParameters.options.no_sticky_threads = true;
-    operateParameters.options.nested_write_transactions = true;
-    mdbx::env_managed env(path, operateParameters);
-
-    //-------------------------------------
-    auto txn = env.start_write();
-    MDBX_txn *c_txn = txn;
-    err = mdbx_txn_reset(txn);
-    assert(err == MDBX_EINVAL);
-    ok = ok && err == MDBX_EINVAL;
-
-    err = mdbx_txn_break(txn);
-    assert(err == MDBX_SUCCESS);
-    ok = ok && err == MDBX_SUCCESS;
-
-    err = mdbx_txn_commit(txn);
-    assert(err == MDBX_RESULT_TRUE);
-    ok = ok && err == MDBX_RESULT_TRUE;
-
-    //-------------------------------------
-    err = mdbx_txn_begin(env, nullptr, MDBX_TXN_READWRITE, &c_txn);
-    assert(err == MDBX_SUCCESS);
-    ok = ok && err == MDBX_SUCCESS;
-    assert(c_txn == (const MDBX_txn *)txn);
-
-    err = mdbx_txn_break(txn);
-    assert(err == MDBX_SUCCESS);
-    ok = ok && err == MDBX_SUCCESS;
-
-    err = mdbx_txn_reset(txn);
-    assert(err == MDBX_EINVAL);
-    ok = ok && err == MDBX_EINVAL;
-
-    err = mdbx_txn_commit(txn);
-    assert(err == MDBX_RESULT_TRUE);
-    ok = ok && err == MDBX_RESULT_TRUE;
-
-    err = mdbx_txn_abort(c_txn);
-    assert(err == MDBX_BAD_TXN);
-    ok = ok && err == MDBX_BAD_TXN;
-    //-------------------------------------
-    err = mdbx_txn_begin(env, nullptr, MDBX_TXN_READWRITE, &c_txn);
-    assert(err == MDBX_SUCCESS);
-    ok = ok && err == MDBX_SUCCESS;
-    assert(c_txn == (const MDBX_txn *)txn);
-    txn.commit();
-
-    err = mdbx_txn_reset(c_txn);
-    assert(err == MDBX_BAD_TXN);
-    ok = ok && err == MDBX_BAD_TXN;
-    err = mdbx_txn_break(c_txn);
-    assert(err == MDBX_BAD_TXN);
-    ok = ok && err == MDBX_BAD_TXN;
-    err = mdbx_txn_abort(c_txn);
-    assert(err == MDBX_BAD_TXN);
-    ok = ok && err == MDBX_BAD_TXN;
-
-    //=====================================
-
-    txn = env.start_read();
-    err = mdbx_txn_begin(env, txn, MDBX_TXN_READWRITE, &c_txn);
-    assert(err == MDBX_BAD_TXN);
-    ok = ok && err == MDBX_BAD_TXN;
-    txn.make_broken();
-    err = mdbx_txn_begin(env, txn, MDBX_TXN_READWRITE, &c_txn);
-    assert(err == MDBX_BAD_TXN);
-    ok = ok && err == MDBX_BAD_TXN;
-    txn.reset_reading();
-    err = mdbx_txn_begin(env, txn, MDBX_TXN_READWRITE, &c_txn);
-    assert(err == MDBX_BAD_TXN);
-    ok = ok && err == MDBX_BAD_TXN;
-    txn.abort();
-
-    //-------------------------------------
-
-    txn = env.start_read();
-    txn.reset_reading();
-    txn.make_broken();
-    txn.abort();
-
-    //=====================================
-
-    std::latch s1(1), s2(1), s3(1);
-    txn = env.start_read();
-    c_txn = txn;
-
-    std::thread t([&]() {
-      s1.wait();
-      err = mdbx_txn_break(c_txn);
-      assert(err == MDBX_SUCCESS);
-      ok = ok && err == MDBX_SUCCESS;
-      err = mdbx_txn_reset(c_txn);
-      assert(err == MDBX_SUCCESS);
-      ok = ok && err == MDBX_SUCCESS;
-      txn.renew_reading();
-      s2.count_down();
-
-      s3.wait();
-      err = mdbx_txn_begin(env, txn, MDBX_TXN_READWRITE, &c_txn);
-      assert(err == MDBX_SUCCESS);
-      ok = ok && err == MDBX_SUCCESS;
-      err = mdbx_txn_commit(c_txn);
-      assert(err == MDBX_SUCCESS);
-      ok = ok && err == MDBX_SUCCESS;
-      c_txn = txn;
-      err = mdbx_txn_commit(c_txn);
-      assert(err == MDBX_THREAD_MISMATCH);
-      ok = ok && err == MDBX_THREAD_MISMATCH;
-      err = mdbx_txn_abort(c_txn);
-      assert(err == MDBX_THREAD_MISMATCH);
-      ok = ok && err == MDBX_THREAD_MISMATCH;
-      err = mdbx_txn_break(c_txn);
-      assert(err == MDBX_SUCCESS);
-      ok = ok && err == MDBX_SUCCESS;
-      err = mdbx_txn_reset(c_txn);
-      assert(err == MDBX_EINVAL);
-      ok = ok && err == MDBX_EINVAL;
-    });
-
-    s1.count_down();
-    s2.wait();
-    txn.commit();
-    txn = env.start_write();
-    s3.count_down();
-
-    t.join();
-    txn.abort();
-  }
+  bool ok = case0(path);
+  ok = case1(path) && ok;
+  ok = case2(path, false) && ok;
+  ok = case2(path, true) && ok;
 
   std::cout << (ok ? "OK\n" : "FAIL\n");
   return ok ? EXIT_SUCCESS : EXIT_FAILURE;