Move sdk sessions tests in to separate directory to reduce timeout impact.

Otherwise there is small possibility starting session keep alive tasks during the run.

9 files changed, 905 insertions, 626 deletions

diff --git a/ydb/services/ydb/CMakeLists.darwin.txt b/ydb/services/ydb/CMakeLists.darwin.txt
index 58fbeb4c3cf..813d577ed81 100644
--- a/ydb/services/ydb/CMakeLists.darwin.txt
+++ b/ydb/services/ydb/CMakeLists.darwin.txt
@@ -9,6 +9,7 @@
 find_package(OpenSSL REQUIRED)
 add_subdirectory(index_ut)
 add_subdirectory(sdk_credprovider_ut)
+add_subdirectory(sdk_sessions_ut)
 add_subdirectory(table_split_ut)
 add_subdirectory(ut)
 
diff --git a/ydb/services/ydb/CMakeLists.linux-aarch64.txt b/ydb/services/ydb/CMakeLists.linux-aarch64.txt
index 788ede8cdfc..2f77c61e3d3 100644
--- a/ydb/services/ydb/CMakeLists.linux-aarch64.txt
+++ b/ydb/services/ydb/CMakeLists.linux-aarch64.txt
@@ -9,6 +9,7 @@
 find_package(OpenSSL REQUIRED)
 add_subdirectory(index_ut)
 add_subdirectory(sdk_credprovider_ut)
+add_subdirectory(sdk_sessions_ut)
 add_subdirectory(table_split_ut)
 add_subdirectory(ut)
 
diff --git a/ydb/services/ydb/CMakeLists.linux.txt b/ydb/services/ydb/CMakeLists.linux.txt
index 788ede8cdfc..2f77c61e3d3 100644
--- a/ydb/services/ydb/CMakeLists.linux.txt
+++ b/ydb/services/ydb/CMakeLists.linux.txt
@@ -9,6 +9,7 @@
 find_package(OpenSSL REQUIRED)
 add_subdirectory(index_ut)
 add_subdirectory(sdk_credprovider_ut)
+add_subdirectory(sdk_sessions_ut)
 add_subdirectory(table_split_ut)
 add_subdirectory(ut)
 
diff --git a/ydb/services/ydb/sdk_sessions_ut/CMakeLists.darwin.txt b/ydb/services/ydb/sdk_sessions_ut/CMakeLists.darwin.txt
new file mode 100644
index 00000000000..a55fad0b0da
--- /dev/null
+++ b/ydb/services/ydb/sdk_sessions_ut/CMakeLists.darwin.txt
@@ -0,0 +1,80 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+
+add_executable(ydb-services-ydb-sdk_sessions_ut)
+target_compile_options(ydb-services-ydb-sdk_sessions_ut PRIVATE
+  -DUSE_CURRENT_UDF_ABI_VERSION
+)
+target_include_directories(ydb-services-ydb-sdk_sessions_ut PRIVATE
+  ${CMAKE_SOURCE_DIR}/ydb/services/ydb
+)
+target_link_libraries(ydb-services-ydb-sdk_sessions_ut PUBLIC
+  contrib-libs-cxxsupp
+  yutil
+  cpp-malloc-system
+  library-cpp-cpuid_check
+  cpp-testing-unittest_main
+  ydb-services-ydb
+  cpp-grpc-client
+  core-testlib-default
+  ydb-core-testlib
+  cpp-client-ydb_table
+)
+target_link_options(ydb-services-ydb-sdk_sessions_ut PRIVATE
+  -Wl,-no_deduplicate
+  -Wl,-sdk_version,10.15
+  -fPIC
+  -fPIC
+  -framework
+  CoreFoundation
+)
+target_sources(ydb-services-ydb-sdk_sessions_ut PRIVATE
+  ${CMAKE_SOURCE_DIR}/ydb/services/ydb/sdk_sessions_ut/sdk_sessions_ut.cpp
+)
+set_property(
+  TARGET
+  ydb-services-ydb-sdk_sessions_ut
+  PROPERTY
+  SPLIT_FACTOR
+  10
+)
+add_yunittest(
+  NAME
+  ydb-services-ydb-sdk_sessions_ut
+  TEST_TARGET
+  ydb-services-ydb-sdk_sessions_ut
+  TEST_ARG
+  --print-before-suite
+  --print-before-test
+  --fork-tests
+  --print-times
+  --show-fails
+)
+set_yunittest_property(
+  TEST
+  ydb-services-ydb-sdk_sessions_ut
+  PROPERTY
+  LABELS
+  MEDIUM
+)
+set_yunittest_property(
+  TEST
+  ydb-services-ydb-sdk_sessions_ut
+  PROPERTY
+  PROCESSORS
+  1
+)
+set_yunittest_property(
+  TEST
+  ydb-services-ydb-sdk_sessions_ut
+  PROPERTY
+  TIMEOUT
+  300
+)
+vcs_info(ydb-services-ydb-sdk_sessions_ut)
diff --git a/ydb/services/ydb/sdk_sessions_ut/CMakeLists.linux-aarch64.txt b/ydb/services/ydb/sdk_sessions_ut/CMakeLists.linux-aarch64.txt
new file mode 100644
index 00000000000..05e4326c4a6
--- /dev/null
+++ b/ydb/services/ydb/sdk_sessions_ut/CMakeLists.linux-aarch64.txt
@@ -0,0 +1,82 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+
+add_executable(ydb-services-ydb-sdk_sessions_ut)
+target_compile_options(ydb-services-ydb-sdk_sessions_ut PRIVATE
+  -DUSE_CURRENT_UDF_ABI_VERSION
+)
+target_include_directories(ydb-services-ydb-sdk_sessions_ut PRIVATE
+  ${CMAKE_SOURCE_DIR}/ydb/services/ydb
+)
+target_link_libraries(ydb-services-ydb-sdk_sessions_ut PUBLIC
+  contrib-libs-linux-headers
+  contrib-libs-cxxsupp
+  yutil
+  library-cpp-lfalloc
+  cpp-testing-unittest_main
+  ydb-services-ydb
+  cpp-grpc-client
+  core-testlib-default
+  ydb-core-testlib
+  cpp-client-ydb_table
+)
+target_link_options(ydb-services-ydb-sdk_sessions_ut PRIVATE
+  -ldl
+  -lrt
+  -Wl,--no-as-needed
+  -fPIC
+  -fPIC
+  -lpthread
+  -lrt
+  -ldl
+)
+target_sources(ydb-services-ydb-sdk_sessions_ut PRIVATE
+  ${CMAKE_SOURCE_DIR}/ydb/services/ydb/sdk_sessions_ut/sdk_sessions_ut.cpp
+)
+set_property(
+  TARGET
+  ydb-services-ydb-sdk_sessions_ut
+  PROPERTY
+  SPLIT_FACTOR
+  10
+)
+add_yunittest(
+  NAME
+  ydb-services-ydb-sdk_sessions_ut
+  TEST_TARGET
+  ydb-services-ydb-sdk_sessions_ut
+  TEST_ARG
+  --print-before-suite
+  --print-before-test
+  --fork-tests
+  --print-times
+  --show-fails
+)
+set_yunittest_property(
+  TEST
+  ydb-services-ydb-sdk_sessions_ut
+  PROPERTY
+  LABELS
+  MEDIUM
+)
+set_yunittest_property(
+  TEST
+  ydb-services-ydb-sdk_sessions_ut
+  PROPERTY
+  PROCESSORS
+  1
+)
+set_yunittest_property(
+  TEST
+  ydb-services-ydb-sdk_sessions_ut
+  PROPERTY
+  TIMEOUT
+  300
+)
+vcs_info(ydb-services-ydb-sdk_sessions_ut)
diff --git a/ydb/services/ydb/sdk_sessions_ut/CMakeLists.linux.txt b/ydb/services/ydb/sdk_sessions_ut/CMakeLists.linux.txt
new file mode 100644
index 00000000000..632434c6262
--- /dev/null
+++ b/ydb/services/ydb/sdk_sessions_ut/CMakeLists.linux.txt
@@ -0,0 +1,84 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+
+add_executable(ydb-services-ydb-sdk_sessions_ut)
+target_compile_options(ydb-services-ydb-sdk_sessions_ut PRIVATE
+  -DUSE_CURRENT_UDF_ABI_VERSION
+)
+target_include_directories(ydb-services-ydb-sdk_sessions_ut PRIVATE
+  ${CMAKE_SOURCE_DIR}/ydb/services/ydb
+)
+target_link_libraries(ydb-services-ydb-sdk_sessions_ut PUBLIC
+  contrib-libs-linux-headers
+  contrib-libs-cxxsupp
+  yutil
+  cpp-malloc-tcmalloc
+  libs-tcmalloc-no_percpu_cache
+  library-cpp-cpuid_check
+  cpp-testing-unittest_main
+  ydb-services-ydb
+  cpp-grpc-client
+  core-testlib-default
+  ydb-core-testlib
+  cpp-client-ydb_table
+)
+target_link_options(ydb-services-ydb-sdk_sessions_ut PRIVATE
+  -ldl
+  -lrt
+  -Wl,--no-as-needed
+  -fPIC
+  -fPIC
+  -lpthread
+  -lrt
+  -ldl
+)
+target_sources(ydb-services-ydb-sdk_sessions_ut PRIVATE
+  ${CMAKE_SOURCE_DIR}/ydb/services/ydb/sdk_sessions_ut/sdk_sessions_ut.cpp
+)
+set_property(
+  TARGET
+  ydb-services-ydb-sdk_sessions_ut
+  PROPERTY
+  SPLIT_FACTOR
+  10
+)
+add_yunittest(
+  NAME
+  ydb-services-ydb-sdk_sessions_ut
+  TEST_TARGET
+  ydb-services-ydb-sdk_sessions_ut
+  TEST_ARG
+  --print-before-suite
+  --print-before-test
+  --fork-tests
+  --print-times
+  --show-fails
+)
+set_yunittest_property(
+  TEST
+  ydb-services-ydb-sdk_sessions_ut
+  PROPERTY
+  LABELS
+  MEDIUM
+)
+set_yunittest_property(
+  TEST
+  ydb-services-ydb-sdk_sessions_ut
+  PROPERTY
+  PROCESSORS
+  1
+)
+set_yunittest_property(
+  TEST
+  ydb-services-ydb-sdk_sessions_ut
+  PROPERTY
+  TIMEOUT
+  300
+)
+vcs_info(ydb-services-ydb-sdk_sessions_ut)
diff --git a/ydb/services/ydb/sdk_sessions_ut/CMakeLists.txt b/ydb/services/ydb/sdk_sessions_ut/CMakeLists.txt
new file mode 100644
index 00000000000..5bb4faffb40
--- /dev/null
+++ b/ydb/services/ydb/sdk_sessions_ut/CMakeLists.txt
@@ -0,0 +1,15 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+if (CMAKE_SYSTEM_PROCESSOR STREQUAL "aarch64" AND UNIX AND NOT APPLE AND NOT ANDROID)
+  include(CMakeLists.linux-aarch64.txt)
+elseif (APPLE AND CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64")
+  include(CMakeLists.darwin.txt)
+elseif (CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64" AND UNIX AND NOT APPLE AND NOT ANDROID)
+  include(CMakeLists.linux.txt)
+endif()
diff --git a/ydb/services/ydb/sdk_sessions_ut/sdk_sessions_ut.cpp b/ydb/services/ydb/sdk_sessions_ut/sdk_sessions_ut.cpp
new file mode 100644
index 00000000000..d4b82e3ab55
--- /dev/null
+++ b/ydb/services/ydb/sdk_sessions_ut/sdk_sessions_ut.cpp
@@ -0,0 +1,641 @@
+#include "ydb_common_ut.h"
+#include <ydb/public/sdk/cpp/client/ydb_table/table.h>
+
+#include <ydb/public/api/grpc/ydb_table_v1.grpc.pb.h>
+
+using namespace NYdb;
+using namespace NYdb::NTable;
+
+Y_UNIT_TEST_SUITE(YdbSdkSessions) {
+    Y_UNIT_TEST(TestSessionPool) {
+        TKikimrWithGrpcAndRootSchema server;
+        ui16 grpc = server.GetPort();
+
+        const TString location = TStringBuilder() << "localhost:" << grpc;
+
+        auto driver = NYdb::TDriver(
+            TDriverConfig()
+                .SetEndpoint(location));
+
+        NYdb::NTable::TTableClient client(driver);
+        int count = 10;
+
+        THashSet<TString> sids;
+        while (count--) {
+            auto sessionResponse = client.GetSession().ExtractValueSync();
+            UNIT_ASSERT_EQUAL(sessionResponse.IsTransportError(), false);
+            auto session = sessionResponse.GetSession();
+            sids.insert(session.GetId());
+            auto result = session.ExecuteDataQuery("SELECT 42;",
+                TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx()).ExtractValueSync();
+
+            UNIT_ASSERT_VALUES_EQUAL(result.GetStatus(), EStatus::SUCCESS);
+            UNIT_ASSERT_VALUES_EQUAL(result.GetEndpoint(), location);
+        }
+        // All requests used one session
+        UNIT_ASSERT_VALUES_EQUAL(sids.size(), 1);
+        // No more session captured by client
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
+
+        driver.Stop(true);
+    }
+
+    Y_UNIT_TEST(TestMultipleSessions) {
+        TKikimrWithGrpcAndRootSchema server;
+        ui16 grpc = server.GetPort();
+
+        TString location = TStringBuilder() << "localhost:" << grpc;
+
+        auto driver = NYdb::TDriver(
+            TDriverConfig()
+                .SetEndpoint(location));
+
+        NYdb::NTable::TTableClient client(driver);
+        int count = 10;
+
+        TVector<TSession> sids;
+        TVector<TAsyncDataQueryResult> results;
+        while (count--) {
+            auto sessionResponse = client.GetSession().ExtractValueSync();
+            UNIT_ASSERT_EQUAL(sessionResponse.IsTransportError(), false);
+            auto session = sessionResponse.GetSession();
+            sids.push_back(session);
+            results.push_back(session.ExecuteDataQuery("SELECT 42;",
+                TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx()));
+        }
+
+        NThreading::WaitExceptionOrAll(results).Wait();
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 10);
+
+        for (auto& result : results) {
+            UNIT_ASSERT_EQUAL(result.GetValue().GetStatus(), EStatus::SUCCESS);
+        }
+        sids.clear();
+        results.clear();
+
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
+
+        driver.Stop(true);
+    }
+
+    Y_UNIT_TEST(TestActiveSessionCountAfterBadSession) {
+        TKikimrWithGrpcAndRootSchema server;
+        ui16 grpc = server.GetPort();
+
+        TString location = TStringBuilder() << "localhost:" << grpc;
+
+        auto driver = NYdb::TDriver(
+            TDriverConfig()
+                .SetEndpoint(location));
+
+        NYdb::NTable::TTableClient client(driver);
+        int count = 10;
+
+        TVector<TSession> sids;
+        TVector<TAsyncDataQueryResult> results;
+        while (count--) {
+            auto sessionResponse = client.GetSession().ExtractValueSync();
+            UNIT_ASSERT_EQUAL(sessionResponse.IsTransportError(), false);
+            auto session = sessionResponse.GetSession();
+            sids.push_back(session);
+            if (count == 0) {
+                // Force BAD session server response for ExecuteDataQuery
+                UNIT_ASSERT_EQUAL(session.Close().GetValueSync().GetStatus(), EStatus::SUCCESS);
+                results.push_back(session.ExecuteDataQuery("SELECT 42;",
+                    TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx()));
+            } else {
+                results.push_back(session.ExecuteDataQuery("SELECT 42;",
+                    TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx()));
+            }
+        }
+
+        NThreading::WaitExceptionOrAll(results).Wait();
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 10);
+
+        for (size_t i = 0; i < results.size(); i++) {
+            if (i == 9) {
+                UNIT_ASSERT_EQUAL(results[i].GetValue().GetStatus(), EStatus::BAD_SESSION);
+            } else {
+                UNIT_ASSERT_EQUAL(results[i].GetValue().GetStatus(), EStatus::SUCCESS);
+            }
+        }
+        sids.clear();
+        results.clear();
+
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
+
+        driver.Stop(true);
+    }
+
+    Y_UNIT_TEST(TestActiveSessionCountAfterTransportError) {
+        TKikimrWithGrpcAndRootSchema server;
+        ui16 grpc = server.GetPort();
+
+        TString location = TStringBuilder() << "localhost:" << grpc;
+
+        auto driver = NYdb::TDriver(
+            TDriverConfig()
+                .SetEndpoint(location));
+
+        NYdb::NTable::TTableClient client(driver);
+        int count = 100;
+
+        {
+            auto sessionResponse = client.GetSession().ExtractValueSync();
+            UNIT_ASSERT(sessionResponse.IsSuccess());
+            auto session = sessionResponse.GetSession();
+            auto result = session.ExecuteSchemeQuery(R"___(
+                CREATE TABLE `Root/Test` (
+                    Key Uint32,
+                    Value String,
+                    PRIMARY KEY (Key)
+                );
+            )___").ExtractValueSync();
+            UNIT_ASSERT(result.IsSuccess());
+            UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
+        }
+
+        while (count--) {
+            auto sessionResponse = client.GetSession().ExtractValueSync();
+            UNIT_ASSERT_EQUAL(sessionResponse.IsTransportError(), false);
+            auto session = sessionResponse.GetSession();
+
+            // Assume 10us is too small to execute query and get response
+            auto res = session.ExecuteDataQuery("SELECT COUNT(*) FROM `Root/Test`;",
+                TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx(),
+                NYdb::NTable::TExecDataQuerySettings().ClientTimeout(TDuration::MicroSeconds(10))).GetValueSync();
+            UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
+        }
+
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
+        driver.Stop(true);
+    }
+
+    Y_UNIT_TEST(MultiThreadSync) {
+        TKikimrWithGrpcAndRootSchema server;
+        ui16 grpc = server.GetPort();
+
+        TString location = TStringBuilder() << "localhost:" << grpc;
+
+        auto driver = NYdb::TDriver(
+            TDriverConfig()
+                .SetEndpoint(location));
+
+        NYdb::NTable::TTableClient client(driver);
+        const int nThreads = 10;
+        const int nRequests = 1000;
+        auto job = [client]() mutable {
+            for (int i = 0; i < nRequests; i++) {
+                auto sessionResponse = client.GetSession().ExtractValueSync();
+                UNIT_ASSERT_EQUAL(sessionResponse.GetStatus(), EStatus::SUCCESS);
+            }
+        };
+        IThreadFactory* pool = SystemThreadFactory();
+
+        TVector<TAutoPtr<IThreadFactory::IThread>> threads;
+        threads.resize(nThreads);
+        for (int i = 0; i < nThreads; i++) {
+            threads[i] = pool->Run(job);
+        }
+        for (int i = 0; i < nThreads; i++) {
+            threads[i]->Join();
+        }
+        UNIT_ASSERT_EQUAL(client.GetActiveSessionCount(), 0);
+        driver.Stop(true);
+    }
+
+    Y_UNIT_TEST(MultiThreadSessionPoolLimitSync) {
+        TKikimrWithGrpcAndRootSchema server;
+        ui16 grpc = server.GetPort();
+
+        TString location = TStringBuilder() << "localhost:" << grpc;
+
+        auto driver = NYdb::TDriver(
+            TDriverConfig()
+                .SetEndpoint(location));
+
+        const int maxActiveSessions = 45;
+        NYdb::NTable::TTableClient client(driver,
+            TClientSettings()
+                .SessionPoolSettings(
+                    TSessionPoolSettings().MaxActiveSessions(maxActiveSessions)));
+
+        constexpr int nThreads = 100;
+        NYdb::EStatus statuses[nThreads];
+        TVector<TMaybe<NYdb::NTable::TSession>> sessions;
+        sessions.resize(nThreads);
+        TAtomic t = 0;
+        auto job = [client, &t, &statuses, &sessions]() mutable {
+            auto sessionResponse = client.GetSession().ExtractValueSync();
+            int i = AtomicIncrement(t);
+            statuses[--i] = sessionResponse.GetStatus();
+            if (statuses[i] == EStatus::SUCCESS) {
+                auto execStatus = sessionResponse.GetSession().ExecuteDataQuery("SELECT 42;",
+                    TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx()).ExtractValueSync().GetStatus();
+                UNIT_ASSERT_EQUAL(execStatus, EStatus::SUCCESS);
+                sessions[i] = sessionResponse.GetSession();
+            }
+        };
+        IThreadFactory* pool = SystemThreadFactory();
+
+        TVector<TAutoPtr<IThreadFactory::IThread>> threads;
+        threads.resize(nThreads);
+        for (int i = 0; i < nThreads; i++) {
+            threads[i] = pool->Run(job);
+        }
+        for (int i = 0; i < nThreads; i++) {
+            threads[i]->Join();
+        }
+
+        sessions.clear();
+
+        int successCount = 0;
+        int exhaustedCount = 0;
+        for (int i = 0; i < nThreads; i++) {
+            switch (statuses[i]) {
+                case EStatus::SUCCESS:
+                    successCount++;
+                    break;
+                case EStatus::CLIENT_RESOURCE_EXHAUSTED:
+                    exhaustedCount++;
+                    break;
+                default:
+                    UNIT_ASSERT(false);
+            }
+        }
+
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
+        UNIT_ASSERT_VALUES_EQUAL(successCount, maxActiveSessions);
+        UNIT_ASSERT_VALUES_EQUAL(exhaustedCount, nThreads - maxActiveSessions);
+        driver.Stop(true);
+    }
+
+    Y_UNIT_TEST(MultiThreadMultipleRequestsOnSharedSessions) {
+        TKikimrWithGrpcAndRootSchema server;
+        ui16 grpc = server.GetPort();
+
+        TString location = TStringBuilder() << "localhost:" << grpc;
+
+        auto driver = NYdb::TDriver(
+            TDriverConfig()
+                .SetEndpoint(location));
+
+        const int maxActiveSessions = 10;
+        NYdb::NTable::TTableClient client(driver,
+            TClientSettings()
+                .SessionPoolSettings(
+                    TSessionPoolSettings().MaxActiveSessions(maxActiveSessions)));
+
+        constexpr int nThreads = 20;
+        constexpr int nRequests = 50;
+        std::array<TVector<TAsyncDataQueryResult>, nThreads> results;
+        TAtomic t = 0;
+        TAtomic validSessions = 0;
+        auto job = [client, &t, &results, &validSessions]() mutable {
+            auto sessionResponse = client.GetSession().ExtractValueSync();
+
+            int i = AtomicIncrement(t);
+            TVector<TAsyncDataQueryResult>& r = results[--i];
+
+            if (sessionResponse.GetStatus() != EStatus::SUCCESS) {
+                return;
+            }
+            AtomicIncrement(validSessions);
+
+            for (int i = 0; i < nRequests; i++) {
+                r.push_back(sessionResponse.GetSession().ExecuteDataQuery("SELECT 42;",
+                    TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx()));
+            }
+        };
+        IThreadFactory* pool = SystemThreadFactory();
+
+        TVector<TAutoPtr<IThreadFactory::IThread>> threads;
+        threads.resize(nThreads);
+        for (int i = 0; i < nThreads; i++) {
+            threads[i] = pool->Run(job);
+        }
+        for (int i = 0; i < nThreads; i++) {
+            threads[i]->Join();
+        }
+
+        for (auto& r : results) {
+            NThreading::WaitExceptionOrAll(r).Wait();
+        }
+        for (auto& r : results) {
+            if (!r.empty()) {
+                int ok = 0;
+                int bad = 0;
+                for (auto& asyncStatus : r) {
+                    auto res = asyncStatus.GetValue();
+                    if (res.IsSuccess()) {
+                        ok++;
+                    } else {
+                        UNIT_ASSERT_VALUES_EQUAL(res.GetStatus(), EStatus::SESSION_BUSY);
+                        bad++;
+                    }
+                }
+                //UNIT_ASSERT_VALUES_EQUAL(ok, 1);
+                //UNIT_ASSERT_VALUES_EQUAL(bad, nRequests - 1);
+            }
+        }
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), maxActiveSessions);
+        auto curExpectedActive = maxActiveSessions;
+        auto empty = 0;
+        for (auto& r : results) {
+            if (!r.empty()) {
+                r.clear();
+                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), --curExpectedActive);
+            } else {
+                empty++;
+            }
+        }
+        UNIT_ASSERT_VALUES_EQUAL(empty, nThreads - maxActiveSessions);
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
+        driver.Stop(true);
+    }
+
+    Y_UNIT_TEST(SessionsServerLimit) {
+        NKikimrConfig::TAppConfig appConfig;
+        auto& tableServiceConfig = *appConfig.MutableTableServiceConfig();
+        tableServiceConfig.SetSessionsLimitPerNode(2);
+
+        TKikimrWithGrpcAndRootSchema server(appConfig);
+
+        NYdb::TDriver driver(TDriverConfig().SetEndpoint(TStringBuilder() << "localhost:" << server.GetPort()));
+        NYdb::NTable::TTableClient client(driver);
+        auto sessionResult = client.CreateSession().ExtractValueSync();
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
+        UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
+        auto session1 = sessionResult.GetSession();
+
+        sessionResult = client.CreateSession().ExtractValueSync();
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
+        UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
+        auto session2 = sessionResult.GetSession();
+
+        sessionResult = client.CreateSession().ExtractValueSync();
+        sessionResult.GetIssues().PrintTo(Cerr);
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
+        UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::OVERLOADED);
+
+        auto status = session1.Close().ExtractValueSync();
+        UNIT_ASSERT_VALUES_EQUAL(status.IsTransportError(), false);
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
+        UNIT_ASSERT_VALUES_EQUAL(status.GetStatus(), EStatus::SUCCESS);
+
+        auto result = session2.ExecuteDataQuery(R"___(
+            SELECT 1;
+        )___", TTxControl::BeginTx().CommitTx()).ExtractValueSync();
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
+        UNIT_ASSERT_VALUES_EQUAL(result.GetStatus(), EStatus::SUCCESS);
+
+        sessionResult = client.CreateSession().ExtractValueSync();
+        UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
+
+        sessionResult = client.CreateSession().ExtractValueSync();
+        sessionResult.GetIssues().PrintTo(Cerr);
+        UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::OVERLOADED);
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
+    }
+
+    Y_UNIT_TEST(SessionsServerLimitWithSessionPool) {
+        NKikimrConfig::TAppConfig appConfig;
+        auto& tableServiceConfig = *appConfig.MutableTableServiceConfig();
+        tableServiceConfig.SetSessionsLimitPerNode(2);
+
+        TKikimrWithGrpcAndRootSchema server(appConfig);
+
+        NYdb::TDriver driver(TDriverConfig().SetEndpoint(TStringBuilder() << "localhost:" << server.GetPort()));
+        NYdb::NTable::TTableClient client(driver);
+        auto sessionResult1 = client.GetSession().ExtractValueSync();
+        UNIT_ASSERT_VALUES_EQUAL(sessionResult1.GetStatus(), EStatus::SUCCESS);
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
+        auto session1 = sessionResult1.GetSession();
+
+        auto sessionResult2 = client.GetSession().ExtractValueSync();
+        UNIT_ASSERT_VALUES_EQUAL(sessionResult2.GetStatus(), EStatus::SUCCESS);
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 2);
+        auto session2 = sessionResult2.GetSession();
+
+        {
+            auto sessionResult3 = client.GetSession().ExtractValueSync();
+            UNIT_ASSERT_VALUES_EQUAL(sessionResult3.GetStatus(), EStatus::OVERLOADED);
+            UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 3);
+        }
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 2);
+
+        auto status = session1.Close().ExtractValueSync();
+        UNIT_ASSERT_VALUES_EQUAL(status.IsTransportError(), false);
+        UNIT_ASSERT_VALUES_EQUAL(status.GetStatus(), EStatus::SUCCESS);
+
+        // Close doesnt free session from user perspective,
+        // the value of ActiveSessionsCounter will be same after Close() call.
+        // Probably we want to chenge this contract
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 2);
+
+        auto result = session2.ExecuteDataQuery(R"___(
+            SELECT 1;
+        )___", TTxControl::BeginTx().CommitTx()).ExtractValueSync();
+        UNIT_ASSERT_VALUES_EQUAL(result.GetStatus(), EStatus::SUCCESS);
+
+        sessionResult1 = client.GetSession().ExtractValueSync();
+        UNIT_ASSERT_VALUES_EQUAL(sessionResult1.GetStatus(), EStatus::SUCCESS);
+        UNIT_ASSERT_VALUES_EQUAL(sessionResult1.GetSession().GetId().empty(), false);
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 3);
+
+        auto sessionResult3 = client.GetSession().ExtractValueSync();
+        UNIT_ASSERT_VALUES_EQUAL(sessionResult3.GetStatus(), EStatus::OVERLOADED);
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 4);
+
+        auto tmp = client.GetSession().ExtractValueSync();
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 5);
+        sessionResult1 = tmp; // here we reset previous created session object,
+                              // so perform close rpc call implicitly and delete it
+        UNIT_ASSERT_VALUES_EQUAL(sessionResult1.GetStatus(), EStatus::OVERLOADED);
+        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 4);
+    }
+
+    Y_UNIT_TEST(CloseSessionAfterDriverDtorWithoutSessionPool) {
+        NKikimrConfig::TAppConfig appConfig;
+
+        TKikimrWithGrpcAndRootSchema server(appConfig);
+
+        TVector<TString> sessionIds;
+        int iterations = 50;
+
+        while (iterations--) {
+            NYdb::TDriver driver(TDriverConfig().SetEndpoint(TStringBuilder() << "localhost:" << server.GetPort()));
+            NYdb::NTable::TTableClient client(driver);
+            auto sessionResult = client.CreateSession().ExtractValueSync();
+            UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
+            UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
+            auto session1 = sessionResult.GetSession();
+            sessionIds.push_back(session1.GetId());
+        }
+
+        std::shared_ptr<grpc::Channel> channel;
+        channel = grpc::CreateChannel("localhost:" + ToString(server.GetPort()), grpc::InsecureChannelCredentials());
+        auto stub = Ydb::Table::V1::TableService::NewStub(channel);
+        for (const auto& sessionId : sessionIds) {
+            grpc::ClientContext context;
+            Ydb::Table::KeepAliveRequest request;
+            request.set_session_id(sessionId);
+            Ydb::Table::KeepAliveResponse response;
+            auto status = stub->KeepAlive(&context, request, &response);
+            UNIT_ASSERT(status.ok());
+            auto deferred = response.operation();
+            UNIT_ASSERT(deferred.ready() == true);
+            UNIT_ASSERT_VALUES_EQUAL(deferred.status(), Ydb::StatusIds::BAD_SESSION);
+        }
+    }
+
+    Y_UNIT_TEST(CloseSessionWithSessionPoolExplicit) {
+        NKikimrConfig::TAppConfig appConfig;
+
+        TKikimrWithGrpcAndRootSchema server(appConfig);
+
+        TVector<TString> sessionIds;
+        int iterations = 100;
+
+        while (iterations--) {
+            NYdb::TDriver driver(TDriverConfig().SetEndpoint(TStringBuilder() << "localhost:" << server.GetPort()));
+            NYdb::NTable::TTableClient client(driver);
+            //TODO: remove this scope after session tracker implementation
+            {
+                auto sessionResult = client.GetSession().ExtractValueSync();
+                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
+                UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
+                auto session1 = sessionResult.GetSession();
+                sessionIds.push_back(session1.GetId());
+
+                sessionResult = client.GetSession().ExtractValueSync();
+                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 2);
+                UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
+                // Here previous created session will be returnet to session pool
+                session1 = sessionResult.GetSession();
+                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
+                sessionIds.push_back(session1.GetId());
+            }
+
+            if (RandomNumber<ui32>(10) == 5) {
+                client.Stop().Apply([client](NThreading::TFuture<void> future){
+                    UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
+                    return future;
+                }).Wait();
+            } else {
+                client.Stop().Wait();
+            }
+
+            if (iterations & 4) {
+                driver.Stop(true);
+            }
+        }
+
+        std::shared_ptr<grpc::Channel> channel;
+        channel = grpc::CreateChannel("localhost:" + ToString(server.GetPort()), grpc::InsecureChannelCredentials());
+        auto stub = Ydb::Table::V1::TableService::NewStub(channel);
+        for (const auto& sessionId : sessionIds) {
+            grpc::ClientContext context;
+            Ydb::Table::KeepAliveRequest request;
+            request.set_session_id(sessionId);
+            Ydb::Table::KeepAliveResponse response;
+            auto status = stub->KeepAlive(&context, request, &response);
+            UNIT_ASSERT(status.ok());
+            auto deferred = response.operation();
+            UNIT_ASSERT(deferred.ready() == true);
+            UNIT_ASSERT(deferred.status() == Ydb::StatusIds::BAD_SESSION);
+        }
+    }
+
+    Y_UNIT_TEST(CloseSessionWithSessionPoolExplicitDriverStopOnly) {
+        NKikimrConfig::TAppConfig appConfig;
+
+        TKikimrWithGrpcAndRootSchema server(appConfig);
+
+        TVector<TString> sessionIds;
+        int iterations = 100;
+
+        while (iterations--) {
+            NYdb::TDriver driver(TDriverConfig().SetEndpoint(TStringBuilder() << "localhost:" << server.GetPort()));
+            NYdb::NTable::TTableClient client(driver);
+            //TODO: remove this scope after session tracker implementation
+            {
+                auto sessionResult = client.GetSession().ExtractValueSync();
+                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
+                UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
+                auto session1 = sessionResult.GetSession();
+                sessionIds.push_back(session1.GetId());
+
+                sessionResult = client.GetSession().ExtractValueSync();
+                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 2);
+                UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
+                // Here previous created session will be returnet to session pool
+                session1 = sessionResult.GetSession();
+                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
+                sessionIds.push_back(session1.GetId());
+            }
+            driver.Stop(true);
+        }
+
+        std::shared_ptr<grpc::Channel> channel;
+        channel = grpc::CreateChannel("localhost:" + ToString(server.GetPort()), grpc::InsecureChannelCredentials());
+        auto stub = Ydb::Table::V1::TableService::NewStub(channel);
+        for (const auto& sessionId : sessionIds) {
+            grpc::ClientContext context;
+            Ydb::Table::KeepAliveRequest request;
+            request.set_session_id(sessionId);
+            Ydb::Table::KeepAliveResponse response;
+            auto status = stub->KeepAlive(&context, request, &response);
+            UNIT_ASSERT(status.ok());
+            auto deferred = response.operation();
+            UNIT_ASSERT(deferred.ready() == true);
+            UNIT_ASSERT(deferred.status() == Ydb::StatusIds::BAD_SESSION);
+        }
+    }
+
+    Y_UNIT_TEST(CloseSessionWithSessionPoolFromDtors) {
+        NKikimrConfig::TAppConfig appConfig;
+
+        TKikimrWithGrpcAndRootSchema server(appConfig);
+
+        TVector<TString> sessionIds;
+        int iterations = 100;
+
+        while (iterations--) {
+            NYdb::TDriver driver(TDriverConfig()
+                .SetEndpoint(TStringBuilder() << "localhost:" << server.GetPort()));
+            NYdb::NTable::TTableClient client(driver);
+            //TODO: remove this scope after session tracker implementation
+            {
+                auto sessionResult = client.GetSession().ExtractValueSync();
+                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
+                UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
+                auto session1 = sessionResult.GetSession();
+                sessionIds.push_back(session1.GetId());
+
+                sessionResult = client.GetSession().ExtractValueSync();
+                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 2);
+                UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
+                // Here previous created session will be returnet to session pool
+                session1 = sessionResult.GetSession();
+                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
+                sessionIds.push_back(session1.GetId());
+            }
+        }
+
+        std::shared_ptr<grpc::Channel> channel;
+        channel = grpc::CreateChannel("localhost:" + ToString(server.GetPort()), grpc::InsecureChannelCredentials());
+        auto stub = Ydb::Table::V1::TableService::NewStub(channel);
+        for (const auto& sessionId : sessionIds) {
+            grpc::ClientContext context;
+            Ydb::Table::KeepAliveRequest request;
+            request.set_session_id(sessionId);
+            Ydb::Table::KeepAliveResponse response;
+            auto status = stub->KeepAlive(&context, request, &response);
+            UNIT_ASSERT(status.ok());
+            auto deferred = response.operation();
+            UNIT_ASSERT(deferred.ready() == true);
+            UNIT_ASSERT(deferred.status() == Ydb::StatusIds::BAD_SESSION);
+        }
+    }
+}
diff --git a/ydb/services/ydb/ydb_table_ut.cpp b/ydb/services/ydb/ydb_table_ut.cpp
index 2aa8cf08b6e..abdf23ece7e 100644
--- a/ydb/services/ydb/ydb_table_ut.cpp
+++ b/ydb/services/ydb/ydb_table_ut.cpp
@@ -239,347 +239,6 @@ Y_UNIT_TEST_SUITE(YdbYqlClient) {
         UNIT_ASSERT_EQUAL(status.GetStatus(), EStatus::SUCCESS);
     }
 
-    Y_UNIT_TEST(TestSessionPool) {
-        TKikimrWithGrpcAndRootSchema server;
-        ui16 grpc = server.GetPort();
-
-        const TString location = TStringBuilder() << "localhost:" << grpc;
-
-        auto driver = NYdb::TDriver(
-            TDriverConfig()
-                .SetEndpoint(location));
-
-        NYdb::NTable::TTableClient client(driver);
-        int count = 10;
-
-        THashSet<TString> sids;
-        while (count--) {
-            auto sessionResponse = client.GetSession().ExtractValueSync();
-            UNIT_ASSERT_EQUAL(sessionResponse.IsTransportError(), false);
-            auto session = sessionResponse.GetSession();
-            sids.insert(session.GetId());
-            auto result = session.ExecuteDataQuery("SELECT 42;",
-                TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx()).ExtractValueSync();
-
-            UNIT_ASSERT_VALUES_EQUAL(result.GetStatus(), EStatus::SUCCESS);
-            UNIT_ASSERT_VALUES_EQUAL(result.GetEndpoint(), location);
-        }
-        // All requests used one session
-        UNIT_ASSERT_VALUES_EQUAL(sids.size(), 1);
-        // No more session captured by client
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
-    }
-
-    Y_UNIT_TEST(TestMultipleSessions) {
-        TKikimrWithGrpcAndRootSchema server;
-        ui16 grpc = server.GetPort();
-
-        TString location = TStringBuilder() << "localhost:" << grpc;
-
-        auto driver = NYdb::TDriver(
-            TDriverConfig()
-                .SetEndpoint(location));
-
-        NYdb::NTable::TTableClient client(driver);
-        int count = 10;
-
-        TVector<TSession> sids;
-        TVector<TAsyncDataQueryResult> results;
-        while (count--) {
-            auto sessionResponse = client.GetSession().ExtractValueSync();
-            UNIT_ASSERT_EQUAL(sessionResponse.IsTransportError(), false);
-            auto session = sessionResponse.GetSession();
-            sids.push_back(session);
-            results.push_back(session.ExecuteDataQuery("SELECT 42;",
-                TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx()));
-        }
-
-        NThreading::WaitExceptionOrAll(results).Wait();
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 10);
-
-        for (auto& result : results) {
-            UNIT_ASSERT_EQUAL(result.GetValue().GetStatus(), EStatus::SUCCESS);
-        }
-        sids.clear();
-        results.clear();
-
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
-    }
-
-    Y_UNIT_TEST(TestActiveSessionCountAfterBadSession) {
-        TKikimrWithGrpcAndRootSchema server;
-        ui16 grpc = server.GetPort();
-
-        TString location = TStringBuilder() << "localhost:" << grpc;
-
-        auto driver = NYdb::TDriver(
-            TDriverConfig()
-                .SetEndpoint(location));
-
-        NYdb::NTable::TTableClient client(driver);
-        int count = 10;
-
-        TVector<TSession> sids;
-        TVector<TAsyncDataQueryResult> results;
-        while (count--) {
-            auto sessionResponse = client.GetSession().ExtractValueSync();
-            UNIT_ASSERT_EQUAL(sessionResponse.IsTransportError(), false);
-            auto session = sessionResponse.GetSession();
-            sids.push_back(session);
-            if (count == 0) {
-                // Force BAD session server response for ExecuteDataQuery
-                UNIT_ASSERT_EQUAL(session.Close().GetValueSync().GetStatus(), EStatus::SUCCESS);
-                results.push_back(session.ExecuteDataQuery("SELECT 42;",
-                    TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx()));
-            } else {
-                results.push_back(session.ExecuteDataQuery("SELECT 42;",
-                    TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx()));
-            }
-        }
-
-        NThreading::WaitExceptionOrAll(results).Wait();
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 10);
-
-        for (size_t i = 0; i < results.size(); i++) {
-            if (i == 9) {
-                UNIT_ASSERT_EQUAL(results[i].GetValue().GetStatus(), EStatus::BAD_SESSION);
-            } else {
-                UNIT_ASSERT_EQUAL(results[i].GetValue().GetStatus(), EStatus::SUCCESS);
-            }
-        }
-        sids.clear();
-        results.clear();
-
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
-    }
-
-    Y_UNIT_TEST(TestActiveSessionCountAfterTransportError) {
-        TKikimrWithGrpcAndRootSchema server;
-        ui16 grpc = server.GetPort();
-
-        TString location = TStringBuilder() << "localhost:" << grpc;
-
-        auto driver = NYdb::TDriver(
-            TDriverConfig()
-                .SetEndpoint(location));
-
-        NYdb::NTable::TTableClient client(driver);
-        int count = 100;
-
-        {
-            auto sessionResponse = client.GetSession().ExtractValueSync();
-            UNIT_ASSERT(sessionResponse.IsSuccess());
-            auto session = sessionResponse.GetSession();
-            auto result = session.ExecuteSchemeQuery(R"___(
-                CREATE TABLE `Root/Test` (
-                    Key Uint32,
-                    Value String,
-                    PRIMARY KEY (Key)
-                );
-            )___").ExtractValueSync();
-            UNIT_ASSERT(result.IsSuccess());
-            UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
-        }
-
-        while (count--) {
-            auto sessionResponse = client.GetSession().ExtractValueSync();
-            UNIT_ASSERT_EQUAL(sessionResponse.IsTransportError(), false);
-            auto session = sessionResponse.GetSession();
-
-            // Assume 10us is too small to execute query and get response
-            auto res = session.ExecuteDataQuery("SELECT COUNT(*) FROM `Root/Test`;",
-                TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx(),
-                NYdb::NTable::TExecDataQuerySettings().ClientTimeout(TDuration::MicroSeconds(10))).GetValueSync();
-            UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
-        }
-
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
-        driver.Stop(true);
-    }
-
-    Y_UNIT_TEST(MultiThreadSync) {
-        TKikimrWithGrpcAndRootSchema server;
-        ui16 grpc = server.GetPort();
-
-        TString location = TStringBuilder() << "localhost:" << grpc;
-
-        auto driver = NYdb::TDriver(
-            TDriverConfig()
-                .SetEndpoint(location));
-
-        NYdb::NTable::TTableClient client(driver);
-        const int nThreads = 10;
-        const int nRequests = 1000;
-        auto job = [client]() mutable {
-            for (int i = 0; i < nRequests; i++) {
-                auto sessionResponse = client.GetSession().ExtractValueSync();
-                UNIT_ASSERT_EQUAL(sessionResponse.GetStatus(), EStatus::SUCCESS);
-            }
-        };
-        IThreadFactory* pool = SystemThreadFactory();
-
-        TVector<TAutoPtr<IThreadFactory::IThread>> threads;
-        threads.resize(nThreads);
-        for (int i = 0; i < nThreads; i++) {
-            threads[i] = pool->Run(job);
-        }
-        for (int i = 0; i < nThreads; i++) {
-            threads[i]->Join();
-        }
-        UNIT_ASSERT_EQUAL(client.GetActiveSessionCount(), 0);
-        driver.Stop(true);
-    }
-
-    Y_UNIT_TEST(MultiThreadSessionPoolLimitSync) {
-        TKikimrWithGrpcAndRootSchema server;
-        ui16 grpc = server.GetPort();
-
-        TString location = TStringBuilder() << "localhost:" << grpc;
-
-        auto driver = NYdb::TDriver(
-            TDriverConfig()
-                .SetEndpoint(location));
-
-        const int maxActiveSessions = 45;
-        NYdb::NTable::TTableClient client(driver,
-            TClientSettings()
-                .SessionPoolSettings(
-                    TSessionPoolSettings().MaxActiveSessions(maxActiveSessions)));
-
-        constexpr int nThreads = 100;
-        NYdb::EStatus statuses[nThreads];
-        TVector<TMaybe<NYdb::NTable::TSession>> sessions;
-        sessions.resize(nThreads);
-        TAtomic t = 0;
-        auto job = [client, &t, &statuses, &sessions]() mutable {
-            auto sessionResponse = client.GetSession().ExtractValueSync();
-            int i = AtomicIncrement(t);
-            statuses[--i] = sessionResponse.GetStatus();
-            if (statuses[i] == EStatus::SUCCESS) {
-                auto execStatus = sessionResponse.GetSession().ExecuteDataQuery("SELECT 42;",
-                    TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx()).ExtractValueSync().GetStatus();
-                UNIT_ASSERT_EQUAL(execStatus, EStatus::SUCCESS);
-                sessions[i] = sessionResponse.GetSession();
-            }
-        };
-        IThreadFactory* pool = SystemThreadFactory();
-
-        TVector<TAutoPtr<IThreadFactory::IThread>> threads;
-        threads.resize(nThreads);
-        for (int i = 0; i < nThreads; i++) {
-            threads[i] = pool->Run(job);
-        }
-        for (int i = 0; i < nThreads; i++) {
-            threads[i]->Join();
-        }
-
-        sessions.clear();
-
-        int successCount = 0;
-        int exhaustedCount = 0;
-        for (int i = 0; i < nThreads; i++) {
-            switch (statuses[i]) {
-                case EStatus::SUCCESS:
-                    successCount++;
-                    break;
-                case EStatus::CLIENT_RESOURCE_EXHAUSTED:
-                    exhaustedCount++;
-                    break;
-                default:
-                    UNIT_ASSERT(false);
-            }
-        }
-
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
-        UNIT_ASSERT_VALUES_EQUAL(successCount, maxActiveSessions);
-        UNIT_ASSERT_VALUES_EQUAL(exhaustedCount, nThreads - maxActiveSessions);
-        driver.Stop(true);
-    }
-
-    Y_UNIT_TEST(MultiThreadMultipleRequestsOnSharedSessions) {
-        TKikimrWithGrpcAndRootSchema server;
-        ui16 grpc = server.GetPort();
-
-        TString location = TStringBuilder() << "localhost:" << grpc;
-
-        auto driver = NYdb::TDriver(
-            TDriverConfig()
-                .SetEndpoint(location));
-
-        const int maxActiveSessions = 10;
-        NYdb::NTable::TTableClient client(driver,
-            TClientSettings()
-                .SessionPoolSettings(
-                    TSessionPoolSettings().MaxActiveSessions(maxActiveSessions)));
-
-        constexpr int nThreads = 20;
-        constexpr int nRequests = 50;
-        std::array<TVector<TAsyncDataQueryResult>, nThreads> results;
-        TAtomic t = 0;
-        TAtomic validSessions = 0;
-        auto job = [client, &t, &results, &validSessions]() mutable {
-            auto sessionResponse = client.GetSession().ExtractValueSync();
-
-            int i = AtomicIncrement(t);
-            TVector<TAsyncDataQueryResult>& r = results[--i];
-
-            if (sessionResponse.GetStatus() != EStatus::SUCCESS) {
-                return;
-            }
-            AtomicIncrement(validSessions);
-
-            for (int i = 0; i < nRequests; i++) {
-                r.push_back(sessionResponse.GetSession().ExecuteDataQuery("SELECT 42;",
-                    TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx()));
-            }
-        };
-        IThreadFactory* pool = SystemThreadFactory();
-
-        TVector<TAutoPtr<IThreadFactory::IThread>> threads;
-        threads.resize(nThreads);
-        for (int i = 0; i < nThreads; i++) {
-            threads[i] = pool->Run(job);
-        }
-        for (int i = 0; i < nThreads; i++) {
-            threads[i]->Join();
-        }
-
-        for (auto& r : results) {
-            NThreading::WaitExceptionOrAll(r).Wait();
-        }
-        for (auto& r : results) {
-            if (!r.empty()) {
-                int ok = 0;
-                int bad = 0;
-                for (auto& asyncStatus : r) {
-                    auto res = asyncStatus.GetValue();
-                    if (res.IsSuccess()) {
-                        ok++;
-                    } else {
-                        UNIT_ASSERT_VALUES_EQUAL(res.GetStatus(), EStatus::SESSION_BUSY);
-                        bad++;
-                    }
-                }
-                //UNIT_ASSERT_VALUES_EQUAL(ok, 1);
-                //UNIT_ASSERT_VALUES_EQUAL(bad, nRequests - 1);
-            }
-        }
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), maxActiveSessions);
-        auto curExpectedActive = maxActiveSessions;
-        auto empty = 0;
-        for (auto& r : results) {
-            if (!r.empty()) {
-                r.clear();
-                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), --curExpectedActive);
-            } else {
-                empty++;
-            }
-        }
-        UNIT_ASSERT_VALUES_EQUAL(empty, nThreads - maxActiveSessions);
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
-        driver.Stop(true);
-    }
-
     Y_UNIT_TEST(TestColumnOrder) {
         TKikimrWithGrpcAndRootSchema server;
         ui16 grpc = server.GetPort();
@@ -2287,291 +1946,6 @@ R"___(<main>: Error: Transaction not found: , code: 2015
         UNIT_ASSERT_EQUAL(result.GetStatus(), EStatus::BAD_REQUEST);
     }
 
-    Y_UNIT_TEST(SessionsServerLimit) {
-        NKikimrConfig::TAppConfig appConfig;
-        auto& tableServiceConfig = *appConfig.MutableTableServiceConfig();
-        tableServiceConfig.SetSessionsLimitPerNode(2);
-
-        TKikimrWithGrpcAndRootSchema server(appConfig);
-
-        NYdb::TDriver driver(TDriverConfig().SetEndpoint(TStringBuilder() << "localhost:" << server.GetPort()));
-        NYdb::NTable::TTableClient client(driver);
-        auto sessionResult = client.CreateSession().ExtractValueSync();
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
-        UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
-        auto session1 = sessionResult.GetSession();
-
-        sessionResult = client.CreateSession().ExtractValueSync();
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
-        UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
-        auto session2 = sessionResult.GetSession();
-
-        sessionResult = client.CreateSession().ExtractValueSync();
-        sessionResult.GetIssues().PrintTo(Cerr);
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
-        UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::OVERLOADED);
-
-        auto status = session1.Close().ExtractValueSync();
-        UNIT_ASSERT_VALUES_EQUAL(status.IsTransportError(), false);
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
-        UNIT_ASSERT_VALUES_EQUAL(status.GetStatus(), EStatus::SUCCESS);
-
-        auto result = session2.ExecuteDataQuery(R"___(
-            SELECT 1;
-        )___", TTxControl::BeginTx().CommitTx()).ExtractValueSync();
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
-        UNIT_ASSERT_VALUES_EQUAL(result.GetStatus(), EStatus::SUCCESS);
-
-        sessionResult = client.CreateSession().ExtractValueSync();
-        UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
-
-        sessionResult = client.CreateSession().ExtractValueSync();
-        sessionResult.GetIssues().PrintTo(Cerr);
-        UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::OVERLOADED);
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
-    }
-
-    Y_UNIT_TEST(SessionsServerLimitWithSessionPool) {
-        NKikimrConfig::TAppConfig appConfig;
-        auto& tableServiceConfig = *appConfig.MutableTableServiceConfig();
-        tableServiceConfig.SetSessionsLimitPerNode(2);
-
-        TKikimrWithGrpcAndRootSchema server(appConfig);
-
-        NYdb::TDriver driver(TDriverConfig().SetEndpoint(TStringBuilder() << "localhost:" << server.GetPort()));
-        NYdb::NTable::TTableClient client(driver);
-        auto sessionResult1 = client.GetSession().ExtractValueSync();
-        UNIT_ASSERT_VALUES_EQUAL(sessionResult1.GetStatus(), EStatus::SUCCESS);
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
-        auto session1 = sessionResult1.GetSession();
-
-        auto sessionResult2 = client.GetSession().ExtractValueSync();
-        UNIT_ASSERT_VALUES_EQUAL(sessionResult2.GetStatus(), EStatus::SUCCESS);
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 2);
-        auto session2 = sessionResult2.GetSession();
-
-        {
-            auto sessionResult3 = client.GetSession().ExtractValueSync();
-            UNIT_ASSERT_VALUES_EQUAL(sessionResult3.GetStatus(), EStatus::OVERLOADED);
-            UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 3);
-        }
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 2);
-
-        auto status = session1.Close().ExtractValueSync();
-        UNIT_ASSERT_VALUES_EQUAL(status.IsTransportError(), false);
-        UNIT_ASSERT_VALUES_EQUAL(status.GetStatus(), EStatus::SUCCESS);
-
-        // Close doesnt free session from user perspective,
-        // the value of ActiveSessionsCounter will be same after Close() call.
-        // Probably we want to chenge this contract
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 2);
-
-        auto result = session2.ExecuteDataQuery(R"___(
-            SELECT 1;
-        )___", TTxControl::BeginTx().CommitTx()).ExtractValueSync();
-        UNIT_ASSERT_VALUES_EQUAL(result.GetStatus(), EStatus::SUCCESS);
-
-        sessionResult1 = client.GetSession().ExtractValueSync();
-        UNIT_ASSERT_VALUES_EQUAL(sessionResult1.GetStatus(), EStatus::SUCCESS);
-        UNIT_ASSERT_VALUES_EQUAL(sessionResult1.GetSession().GetId().empty(), false);
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 3);
-
-        auto sessionResult3 = client.GetSession().ExtractValueSync();
-        UNIT_ASSERT_VALUES_EQUAL(sessionResult3.GetStatus(), EStatus::OVERLOADED);
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 4);
-
-        auto tmp = client.GetSession().ExtractValueSync();
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 5);
-        sessionResult1 = tmp; // here we reset previous created session object,
-                              // so perform close rpc call implicitly and delete it
-        UNIT_ASSERT_VALUES_EQUAL(sessionResult1.GetStatus(), EStatus::OVERLOADED);
-        UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 4);
-    }
-
-    Y_UNIT_TEST(CloseSessionAfterDriverDtorWithoutSessionPool) {
-        NKikimrConfig::TAppConfig appConfig;
-
-        TKikimrWithGrpcAndRootSchema server(appConfig);
-
-        TVector<TString> sessionIds;
-        int iterations = 50;
-
-        while (iterations--) {
-            NYdb::TDriver driver(TDriverConfig().SetEndpoint(TStringBuilder() << "localhost:" << server.GetPort()));
-            NYdb::NTable::TTableClient client(driver);
-            auto sessionResult = client.CreateSession().ExtractValueSync();
-            UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
-            UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
-            auto session1 = sessionResult.GetSession();
-            sessionIds.push_back(session1.GetId());
-        }
-
-        std::shared_ptr<grpc::Channel> channel;
-        channel = grpc::CreateChannel("localhost:" + ToString(server.GetPort()), grpc::InsecureChannelCredentials());
-        auto stub = Ydb::Table::V1::TableService::NewStub(channel);
-        for (const auto& sessionId : sessionIds) {
-            grpc::ClientContext context;
-            Ydb::Table::KeepAliveRequest request;
-            request.set_session_id(sessionId);
-            Ydb::Table::KeepAliveResponse response;
-            auto status = stub->KeepAlive(&context, request, &response);
-            UNIT_ASSERT(status.ok());
-            auto deferred = response.operation();
-            UNIT_ASSERT(deferred.ready() == true);
-            UNIT_ASSERT_VALUES_EQUAL(deferred.status(), Ydb::StatusIds::BAD_SESSION);
-        }
-    }
-
-    Y_UNIT_TEST(CloseSessionWithSessionPoolExplicit) {
-        NKikimrConfig::TAppConfig appConfig;
-
-        TKikimrWithGrpcAndRootSchema server(appConfig);
-
-        TVector<TString> sessionIds;
-        int iterations = 100;
-
-        while (iterations--) {
-            NYdb::TDriver driver(TDriverConfig().SetEndpoint(TStringBuilder() << "localhost:" << server.GetPort()));
-            NYdb::NTable::TTableClient client(driver);
-            //TODO: remove this scope after session tracker implementation
-            {
-                auto sessionResult = client.GetSession().ExtractValueSync();
-                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
-                UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
-                auto session1 = sessionResult.GetSession();
-                sessionIds.push_back(session1.GetId());
-
-                sessionResult = client.GetSession().ExtractValueSync();
-                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 2);
-                UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
-                // Here previous created session will be returnet to session pool
-                session1 = sessionResult.GetSession();
-                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
-                sessionIds.push_back(session1.GetId());
-            }
-
-            if (RandomNumber<ui32>(10) == 5) {
-                client.Stop().Apply([client](NThreading::TFuture<void> future){
-                    UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 0);
-                    return future;
-                }).Wait();
-            } else {
-                client.Stop().Wait();
-            }
-
-            if (iterations & 4) {
-                driver.Stop(true);
-            }
-        }
-
-        std::shared_ptr<grpc::Channel> channel;
-        channel = grpc::CreateChannel("localhost:" + ToString(server.GetPort()), grpc::InsecureChannelCredentials());
-        auto stub = Ydb::Table::V1::TableService::NewStub(channel);
-        for (const auto& sessionId : sessionIds) {
-            grpc::ClientContext context;
-            Ydb::Table::KeepAliveRequest request;
-            request.set_session_id(sessionId);
-            Ydb::Table::KeepAliveResponse response;
-            auto status = stub->KeepAlive(&context, request, &response);
-            UNIT_ASSERT(status.ok());
-            auto deferred = response.operation();
-            UNIT_ASSERT(deferred.ready() == true);
-            UNIT_ASSERT(deferred.status() == Ydb::StatusIds::BAD_SESSION);
-        }
-    }
-
-    Y_UNIT_TEST(CloseSessionWithSessionPoolExplicitDriverStopOnly) {
-        NKikimrConfig::TAppConfig appConfig;
-
-        TKikimrWithGrpcAndRootSchema server(appConfig);
-
-        TVector<TString> sessionIds;
-        int iterations = 100;
-
-        while (iterations--) {
-            NYdb::TDriver driver(TDriverConfig().SetEndpoint(TStringBuilder() << "localhost:" << server.GetPort()));
-            NYdb::NTable::TTableClient client(driver);
-            //TODO: remove this scope after session tracker implementation
-            {
-                auto sessionResult = client.GetSession().ExtractValueSync();
-                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
-                UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
-                auto session1 = sessionResult.GetSession();
-                sessionIds.push_back(session1.GetId());
-
-                sessionResult = client.GetSession().ExtractValueSync();
-                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 2);
-                UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
-                // Here previous created session will be returnet to session pool
-                session1 = sessionResult.GetSession();
-                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
-                sessionIds.push_back(session1.GetId());
-            }
-            driver.Stop(true);
-        }
-
-        std::shared_ptr<grpc::Channel> channel;
-        channel = grpc::CreateChannel("localhost:" + ToString(server.GetPort()), grpc::InsecureChannelCredentials());
-        auto stub = Ydb::Table::V1::TableService::NewStub(channel);
-        for (const auto& sessionId : sessionIds) {
-            grpc::ClientContext context;
-            Ydb::Table::KeepAliveRequest request;
-            request.set_session_id(sessionId);
-            Ydb::Table::KeepAliveResponse response;
-            auto status = stub->KeepAlive(&context, request, &response);
-            UNIT_ASSERT(status.ok());
-            auto deferred = response.operation();
-            UNIT_ASSERT(deferred.ready() == true);
-            UNIT_ASSERT(deferred.status() == Ydb::StatusIds::BAD_SESSION);
-        }
-    }
-
-    Y_UNIT_TEST(CloseSessionWithSessionPoolFromDtors) {
-        NKikimrConfig::TAppConfig appConfig;
-
-        TKikimrWithGrpcAndRootSchema server(appConfig);
-
-        TVector<TString> sessionIds;
-        int iterations = 100;
-
-        while (iterations--) {
-            NYdb::TDriver driver(TDriverConfig()
-                .SetEndpoint(TStringBuilder() << "localhost:" << server.GetPort()));
-            NYdb::NTable::TTableClient client(driver);
-            //TODO: remove this scope after session tracker implementation
-            {
-                auto sessionResult = client.GetSession().ExtractValueSync();
-                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
-                UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
-                auto session1 = sessionResult.GetSession();
-                sessionIds.push_back(session1.GetId());
-
-                sessionResult = client.GetSession().ExtractValueSync();
-                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 2);
-                UNIT_ASSERT_VALUES_EQUAL(sessionResult.GetStatus(), EStatus::SUCCESS);
-                // Here previous created session will be returnet to session pool
-                session1 = sessionResult.GetSession();
-                UNIT_ASSERT_VALUES_EQUAL(client.GetActiveSessionCount(), 1);
-                sessionIds.push_back(session1.GetId());
-            }
-        }
-
-        std::shared_ptr<grpc::Channel> channel;
-        channel = grpc::CreateChannel("localhost:" + ToString(server.GetPort()), grpc::InsecureChannelCredentials());
-        auto stub = Ydb::Table::V1::TableService::NewStub(channel);
-        for (const auto& sessionId : sessionIds) {
-            grpc::ClientContext context;
-            Ydb::Table::KeepAliveRequest request;
-            request.set_session_id(sessionId);
-            Ydb::Table::KeepAliveResponse response;
-            auto status = stub->KeepAlive(&context, request, &response);
-            UNIT_ASSERT(status.ok());
-            auto deferred = response.operation();
-            UNIT_ASSERT(deferred.ready() == true);
-            UNIT_ASSERT(deferred.status() == Ydb::StatusIds::BAD_SESSION);
-        }
-    }
-
     Y_UNIT_TEST(DeleteTableWithDeletedIndex) {
         TKikimrWithGrpcAndRootSchema server;