diff --git a/docker/test/integration/runner/Dockerfile b/docker/test/integration/runner/Dockerfile
index 56abf1122b2..f353931f0a0 100644
--- a/docker/test/integration/runner/Dockerfile
+++ b/docker/test/integration/runner/Dockerfile
@@ -63,6 +63,7 @@ RUN python3 -m pip install \
     cassandra-driver \
     confluent-kafka \
     dict2xml \
+    dicttoxml \
     docker \
     docker-compose==1.22.0 \
     grpcio \
diff --git a/docker/test/stateless/run.sh b/docker/test/stateless/run.sh
index fb510a87fcd..575be721a54 100755
--- a/docker/test/stateless/run.sh
+++ b/docker/test/stateless/run.sh
@@ -53,10 +53,12 @@ function run_tests()
     if [ "$NUM_TRIES" -gt "1" ]; then
         ADDITIONAL_OPTIONS+=('--skip')
         ADDITIONAL_OPTIONS+=('00000_no_tests_to_skip')
+        ADDITIONAL_OPTIONS+=('--jobs')
+        ADDITIONAL_OPTIONS+=('4')
     fi
 
     clickhouse-test --testname --shard --zookeeper --hung-check --print-time \
-            --test-runs "$NUM_TRIES" --jobs 4 \
+            --test-runs "$NUM_TRIES" \
             "$SKIP_LIST_OPT" "${ADDITIONAL_OPTIONS[@]}" 2>&1 \
         | ts '%Y-%m-%d %H:%M:%S' \
         | tee -a test_output/test_result.txt
diff --git a/src/Client/tests/CMakeLists.txt b/src/Client/tests/CMakeLists.txt
index e69de29bb2d..d952c006bb5 100644
--- a/src/Client/tests/CMakeLists.txt
+++ b/src/Client/tests/CMakeLists.txt
@@ -0,0 +1,2 @@
+add_executable(test-connect test_connect.cpp)
+target_link_libraries (test-connect PRIVATE dbms)
diff --git a/src/Client/tests/test_connect.cpp b/src/Client/tests/test_connect.cpp
new file mode 100644
index 00000000000..1259980f9a6
--- /dev/null
+++ b/src/Client/tests/test_connect.cpp
@@ -0,0 +1,99 @@
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include <iostream>
+#include <thread>
+#include <atomic>
+#include <Poco/Net/StreamSocket.h>
+#include <Common/Exception.h>
+#include <Common/Stopwatch.h>
+#include <IO/ReadHelpers.h>
+
+
+/** In a loop it connects to the server and immediately breaks the connection.
+  * Using the SO_LINGER option, we ensure that the connection is terminated by sending a RST packet (not FIN).
+  * Long time ago this behavior caused a bug in the TCPServer implementation in the Poco library.
+  */
+int main(int argc, char ** argv)
+try
+{
+    size_t num_iterations = 1;
+    size_t num_threads = 1;
+    std::string host = "localhost";
+    uint16_t port = 9000;
+
+    if (argc >= 2)
+        num_iterations = DB::parse<size_t>(argv[1]);
+
+    if (argc >= 3)
+        num_threads = DB::parse<size_t>(argv[2]);
+
+    if (argc >= 4)
+        host = argv[3];
+
+    if (argc >= 5)
+        port = DB::parse<uint16_t>(argv[4]);
+
+    std::atomic_bool cancel{false};
+    std::vector<std::thread> threads(num_threads);
+    for (auto & thread : threads)
+    {
+        thread = std::thread([&]
+        {
+            for (size_t i = 0; i < num_iterations && !cancel.load(std::memory_order_relaxed); ++i)
+            {
+                std::cerr << ".";
+
+                Poco::Net::SocketAddress address(host, port);
+
+                int fd = socket(PF_INET, SOCK_STREAM, IPPROTO_IP);
+
+                if (fd < 0)
+                    DB::throwFromErrno("Cannot create socket", 0);
+
+                linger linger_value;
+                linger_value.l_onoff = 1;
+                linger_value.l_linger = 0;
+
+                if (0 != setsockopt(fd, SOL_SOCKET, SO_LINGER, &linger_value, sizeof(linger_value)))
+                    DB::throwFromErrno("Cannot set linger", 0);
+
+                try
+                {
+                    Stopwatch watch;
+
+                    int res = connect(fd, address.addr(), address.length());
+
+                    if (res != 0 && errno != EINPROGRESS && errno != EWOULDBLOCK)
+                    {
+                        close(fd);
+                        DB::throwFromErrno("Cannot connect", 0);
+                    }
+
+                    close(fd);
+
+                    if (watch.elapsedSeconds() > 0.1)
+                    {
+                        std::cerr << watch.elapsedSeconds() << "\n";
+                        cancel = true;
+                        break;
+                    }
+                }
+                catch (const Poco::Exception & e)
+                {
+                    std::cerr << e.displayText() << "\n";
+                }
+            }
+        });
+    }
+
+    for (auto & thread : threads)
+        thread.join();
+
+    std::cerr << "\n";
+}
+catch (const Poco::Exception & e)
+{
+    std::cerr << e.displayText() << "\n";
+}
diff --git a/src/Core/MySQL/MySQLClient.cpp b/src/Core/MySQL/MySQLClient.cpp
index f65fbe62274..e41b4128738 100644
--- a/src/Core/MySQL/MySQLClient.cpp
+++ b/src/Core/MySQL/MySQLClient.cpp
@@ -6,8 +6,10 @@
 #include <Core/MySQL/PacketsProtocolText.h>
 #include <Core/MySQL/PacketsReplication.h>
 #include <Core/MySQL/MySQLReplication.h>
+#include <Common/DNSResolver.h>
 #include <Poco/String.h>
 
+
 namespace DB
 {
 using namespace Generic;
diff --git a/src/Core/MySQL/MySQLClient.h b/src/Core/MySQL/MySQLClient.h
index 5835e980149..e503c985584 100644
--- a/src/Core/MySQL/MySQLClient.h
+++ b/src/Core/MySQL/MySQLClient.h
@@ -7,7 +7,6 @@
 #include <IO/WriteHelpers.h>
 #include <Poco/Net/NetException.h>
 #include <Poco/Net/StreamSocket.h>
-#include <Common/DNSResolver.h>
 #include <Common/Exception.h>
 #include <Common/NetException.h>
 #include <Core/MySQL/IMySQLWritePacket.h>
diff --git a/src/Dictionaries/XDBCDictionarySource.cpp b/src/Dictionaries/XDBCDictionarySource.cpp
index aa27f4efc25..3615f72605f 100644
--- a/src/Dictionaries/XDBCDictionarySource.cpp
+++ b/src/Dictionaries/XDBCDictionarySource.cpp
@@ -21,7 +21,7 @@
 #include "registerDictionaries.h"
 
 #if USE_ODBC
-#    include <Poco/Data/ODBC/Connector.h>
+#    include <Poco/Data/ODBC/Connector.h> // Y_IGNORE
 #endif
 
 namespace DB
diff --git a/src/Dictionaries/ya.make b/src/Dictionaries/ya.make
index f754f250b38..4f33dc80559 100644
--- a/src/Dictionaries/ya.make
+++ b/src/Dictionaries/ya.make
@@ -6,12 +6,15 @@ LIBRARY()
 PEERDIR(
     clickhouse/src/Common
     contrib/libs/poco/Data
-    contrib/libs/poco/Data/ODBC
     contrib/libs/poco/MongoDB
     contrib/libs/poco/Redis
     contrib/libs/sparsehash
 )
 
+IF (USE_ODBC)
+    PEERDIR(contrib/libs/poco/Data/ODBC)
+ENDIF ()
+
 NO_COMPILER_WARNINGS()
 
 
diff --git a/src/Dictionaries/ya.make.in b/src/Dictionaries/ya.make.in
index 5df5803e7f4..e52b106d034 100644
--- a/src/Dictionaries/ya.make.in
+++ b/src/Dictionaries/ya.make.in
@@ -5,12 +5,15 @@ LIBRARY()
 PEERDIR(
     clickhouse/src/Common
     contrib/libs/poco/Data
-    contrib/libs/poco/Data/ODBC
     contrib/libs/poco/MongoDB
     contrib/libs/poco/Redis
     contrib/libs/sparsehash
 )
 
+IF (USE_ODBC)
+    PEERDIR(contrib/libs/poco/Data/ODBC)
+ENDIF ()
+
 NO_COMPILER_WARNINGS()
 
 
diff --git a/src/Interpreters/Context.cpp b/src/Interpreters/Context.cpp
index fc8d8654573..77f4bc976cd 100644
--- a/src/Interpreters/Context.cpp
+++ b/src/Interpreters/Context.cpp
@@ -50,7 +50,6 @@
 #include <Interpreters/SystemLog.h>
 #include <Interpreters/Context.h>
 #include <Interpreters/DDLWorker.h>
-#include <Common/DNSResolver.h>
 #include <IO/ReadBufferFromFile.h>
 #include <IO/UncompressedCache.h>
 #include <Parsers/ASTCreateQuery.h>
diff --git a/src/Interpreters/executeQuery.cpp b/src/Interpreters/executeQuery.cpp
index 020e5af365a..50e891a3524 100644
--- a/src/Interpreters/executeQuery.cpp
+++ b/src/Interpreters/executeQuery.cpp
@@ -51,7 +51,6 @@
 #include <Interpreters/Context.h>
 #include <Common/ProfileEvents.h>
 
-#include <Interpreters/DNSCacheUpdater.h>
 #include <Common/SensitiveDataMasker.h>
 
 #include <Processors/Transforms/LimitsCheckingTransform.h>
diff --git a/src/Storages/System/StorageSystemClusters.cpp b/src/Storages/System/StorageSystemClusters.cpp
index 83d165f54f7..ae8bcca2804 100644
--- a/src/Storages/System/StorageSystemClusters.cpp
+++ b/src/Storages/System/StorageSystemClusters.cpp
@@ -1,4 +1,3 @@
-#include <Common/DNSResolver.h>
 #include <DataTypes/DataTypeString.h>
 #include <DataTypes/DataTypesNumber.h>
 #include <Interpreters/Cluster.h>