Ydb stable 23-2-1123.2.11

x-stable-origin-commit: 758ace972646c843c5e0785d75c8f4fe044580a1

26 files changed, 679 insertions, 49 deletions

diff --git a/library/cpp/actors/interconnect/CMakeLists.darwin.txt b/library/cpp/actors/interconnect/CMakeLists.darwin.txt
index c0b4981c37..4d13e9ec54 100644
--- a/library/cpp/actors/interconnect/CMakeLists.darwin.txt
+++ b/library/cpp/actors/interconnect/CMakeLists.darwin.txt
@@ -10,6 +10,7 @@ find_package(OpenSSL REQUIRED)
 add_subdirectory(mock)
 add_subdirectory(ut)
 add_subdirectory(ut_fat)
+add_subdirectory(ut_huge_cluster)
 
 add_library(cpp-actors-interconnect)
 target_link_libraries(cpp-actors-interconnect PUBLIC
diff --git a/library/cpp/actors/interconnect/CMakeLists.linux-aarch64.txt b/library/cpp/actors/interconnect/CMakeLists.linux-aarch64.txt
index ada1e68d25..4142c4c6b5 100644
--- a/library/cpp/actors/interconnect/CMakeLists.linux-aarch64.txt
+++ b/library/cpp/actors/interconnect/CMakeLists.linux-aarch64.txt
@@ -10,6 +10,7 @@ find_package(OpenSSL REQUIRED)
 add_subdirectory(mock)
 add_subdirectory(ut)
 add_subdirectory(ut_fat)
+add_subdirectory(ut_huge_cluster)
 
 add_library(cpp-actors-interconnect)
 target_link_libraries(cpp-actors-interconnect PUBLIC
diff --git a/library/cpp/actors/interconnect/CMakeLists.linux.txt b/library/cpp/actors/interconnect/CMakeLists.linux.txt
index ada1e68d25..4142c4c6b5 100644
--- a/library/cpp/actors/interconnect/CMakeLists.linux.txt
+++ b/library/cpp/actors/interconnect/CMakeLists.linux.txt
@@ -10,6 +10,7 @@ find_package(OpenSSL REQUIRED)
 add_subdirectory(mock)
 add_subdirectory(ut)
 add_subdirectory(ut_fat)
+add_subdirectory(ut_huge_cluster)
 
 add_library(cpp-actors-interconnect)
 target_link_libraries(cpp-actors-interconnect PUBLIC
diff --git a/library/cpp/actors/interconnect/events_local.h b/library/cpp/actors/interconnect/events_local.h
index b1b8ae0c75..966cdb763e 100644
--- a/library/cpp/actors/interconnect/events_local.h
+++ b/library/cpp/actors/interconnect/events_local.h
@@ -52,6 +52,9 @@ namespace NActors {
         EvProcessPingRequest,
         EvGetSecureSocket,
         EvSecureSocket,
+        HandshakeBrokerTake,
+        HandshakeBrokerFree,
+        HandshakeBrokerPermit,
 
         ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
         // nonlocal messages; their indices must be preserved in order to work properly while doing rolling update
@@ -98,6 +101,18 @@ namespace NActors {
         }
     };
 
+    struct TEvHandshakeBrokerTake: TEventLocal<TEvHandshakeBrokerTake, ui32(ENetwork::HandshakeBrokerTake)> {
+        DEFINE_SIMPLE_LOCAL_EVENT(TEvHandshakeBrokerTake, "Network: TEvHandshakeBrokerTake")
+    };
+
+    struct TEvHandshakeBrokerFree: TEventLocal<TEvHandshakeBrokerFree, ui32(ENetwork::HandshakeBrokerFree)> {
+        DEFINE_SIMPLE_LOCAL_EVENT(TEvHandshakeBrokerFree, "Network: TEvHandshakeBrokerFree")
+    };
+
+    struct TEvHandshakeBrokerPermit: TEventLocal<TEvHandshakeBrokerPermit, ui32(ENetwork::HandshakeBrokerPermit)> {
+        DEFINE_SIMPLE_LOCAL_EVENT(TEvHandshakeBrokerPermit, "Network: TEvHandshakeBrokerPermit")
+    };
+
     struct TEvHandshakeAsk: public TEventLocal<TEvHandshakeAsk, ui32(ENetwork::HandshakeAsk)> {
         DEFINE_SIMPLE_LOCAL_EVENT(TEvHandshakeAsk, "Network: TEvHandshakeAsk")
         TEvHandshakeAsk(const TActorId& self,
diff --git a/library/cpp/actors/interconnect/handshake_broker.h b/library/cpp/actors/interconnect/handshake_broker.h
new file mode 100644
index 0000000000..9910fb4b71
--- /dev/null
+++ b/library/cpp/actors/interconnect/handshake_broker.h
@@ -0,0 +1,157 @@
+#pragma once
+
+#include <library/cpp/actors/core/actor.h>
+#include <library/cpp/actors/core/hfunc.h>
+#include <library/cpp/actors/interconnect/events_local.h>
+
+#include <deque>
+
+namespace NActors {
+    class TBrokerLeaseHolder {
+    public:
+        TBrokerLeaseHolder(TActorSystem* actorSystem, TActorId waiterId, TActorId brokerId)
+            : ActorSystem(actorSystem)
+            , WaiterId(waiterId)
+            , BrokerId(brokerId) {
+            if (ActorSystem->Send(new IEventHandle(BrokerId, WaiterId, new TEvHandshakeBrokerTake()))) {
+                LeaseRequested = true;
+            }
+        }
+
+        ~TBrokerLeaseHolder() {
+            if (LeaseRequested) {
+                ActorSystem->Send(new IEventHandle(BrokerId, WaiterId, new TEvHandshakeBrokerFree()));
+            }
+        }
+
+        bool IsLeaseRequested() {
+            return LeaseRequested;
+        }
+
+        void ForgetLease() {
+            // only call when TDtorException was caught
+            LeaseRequested = false;
+        }
+
+    private:
+        TActorSystem* ActorSystem;
+        TActorId WaiterId;
+        TActorId BrokerId;
+        bool LeaseRequested = false;
+    };
+
+    class THandshakeBroker : public TActor<THandshakeBroker> {
+    private:
+        enum class ESelectionStrategy {
+            FIFO = 0,
+            LIFO,
+            Random,
+        };
+
+    private:
+        void PermitNext() {
+            if (Capacity == 0 && !Waiters.empty()) {
+                TActorId waiter;
+
+                switch (SelectionStrategy) {
+                case ESelectionStrategy::FIFO:
+                    waiter = Waiters.front();
+                    Waiters.pop_front();
+                    SelectionStrategy = ESelectionStrategy::LIFO;
+                    break;
+
+                case ESelectionStrategy::LIFO:
+                    waiter = Waiters.back();
+                    Waiters.pop_back();
+                    SelectionStrategy = ESelectionStrategy::Random;
+                    break;
+
+                case ESelectionStrategy::Random: {
+                    const auto it = WaiterLookup.begin();
+                    waiter = it->first;
+                    Waiters.erase(it->second);
+                    SelectionStrategy = ESelectionStrategy::FIFO;
+                    break;
+                }
+
+                default:
+                    Y_FAIL("Unimplimented selection strategy");
+                }
+
+                const size_t n = WaiterLookup.erase(waiter);
+                Y_VERIFY(n == 1);
+
+                Send(waiter, new TEvHandshakeBrokerPermit());
+                PermittedLeases.insert(waiter);
+            } else {
+                Capacity += 1;
+            }
+        }
+
+    private:
+        using TWaiters = std::list<TActorId>;
+        TWaiters Waiters;
+        std::unordered_map<TActorId, TWaiters::iterator> WaiterLookup;
+        std::unordered_set<TActorId> PermittedLeases;
+
+        ESelectionStrategy SelectionStrategy = ESelectionStrategy::FIFO;
+
+        ui32 Capacity;
+
+        void Handle(TEvHandshakeBrokerTake::TPtr &ev) {
+            const TActorId sender = ev->Sender;
+            if (Capacity > 0) {
+                Capacity -= 1;
+                PermittedLeases.insert(sender);
+                Send(sender, new TEvHandshakeBrokerPermit());
+            } else {
+                const auto [it, inserted] = WaiterLookup.try_emplace(sender,
+                        Waiters.insert(Waiters.end(), sender));
+                Y_VERIFY(inserted);
+            }
+        }
+
+        void Handle(TEvHandshakeBrokerFree::TPtr& ev) {
+            const TActorId sender = ev->Sender;
+            if (!PermittedLeases.erase(sender)) {
+                // Lease was not permitted yet, remove sender from Waiters queue
+                const auto it = WaiterLookup.find(sender);
+                Y_VERIFY(it != WaiterLookup.end());
+                Waiters.erase(it->second);
+                WaiterLookup.erase(it);
+            }
+            PermitNext();
+        }
+
+    public:
+        THandshakeBroker(ui32 inflightLimit)
+            : TActor(&TThis::StateFunc)
+            , Capacity(inflightLimit)
+        {
+        }
+
+        STFUNC(StateFunc) {
+            Y_UNUSED(ctx);
+            switch (ev->GetTypeRewrite()) {
+                hFunc(TEvHandshakeBrokerTake, Handle);
+                hFunc(TEvHandshakeBrokerFree, Handle);
+
+            default:
+                Y_FAIL("unexpected event 0x%08" PRIx32, ev->GetTypeRewrite());
+            }
+        }
+
+        void Bootstrap() {
+            Become(&TThis::StateFunc);
+        };
+    };
+
+    inline IActor* CreateHandshakeBroker(ui32 maxCapacity) {
+        return new THandshakeBroker(maxCapacity);
+    }
+
+    inline TActorId MakeHandshakeBrokerOutId() {
+        char x[12] = {'I', 'C', 'H', 's', 'h', 'k', 'B', 'r', 'k', 'O', 'u', 't'};
+        return TActorId(0, TStringBuf(std::begin(x), std::end(x)));
+    }
+};
diff --git a/library/cpp/actors/interconnect/interconnect_common.h b/library/cpp/actors/interconnect/interconnect_common.h
index ea6a5310d4..d526621491 100644
--- a/library/cpp/actors/interconnect/interconnect_common.h
+++ b/library/cpp/actors/interconnect/interconnect_common.h
@@ -48,6 +48,7 @@ namespace NActors {
         ui32 MaxSerializedEventSize = NActors::EventMaxByteSize;
         ui32 PreallocatedBufferSize = 8 << 10; // 8 KB
         ui32 NumPreallocatedBuffers = 16;
+        ui32 SocketBacklogSize = 0; // SOMAXCONN if zero
 
         ui32 GetSendBufferSize() const {
             ui32 res = 512 * 1024; // 512 kb is the default value for send buffer
@@ -94,6 +95,7 @@ namespace NActors {
         std::shared_ptr<TEventFilter> EventFilter;
         TString Cookie; // unique random identifier of a node instance (generated randomly at every start)
         std::unordered_map<ui16, TString> ChannelName;
+        std::optional<ui32> OutgoingHandshakeInflightLimit;
 
         struct TVersionInfo {
             TString Tag; // version tag for this node
diff --git a/library/cpp/actors/interconnect/interconnect_handshake.cpp b/library/cpp/actors/interconnect/interconnect_handshake.cpp
index dc651f3762..8d281ae52e 100644
--- a/library/cpp/actors/interconnect/interconnect_handshake.cpp
+++ b/library/cpp/actors/interconnect/interconnect_handshake.cpp
@@ -1,4 +1,5 @@
 #include "interconnect_handshake.h"
+#include "handshake_broker.h"
 #include "interconnect_tcp_proxy.h"
 
 #include <library/cpp/actors/core/actor_coroutine.h>
@@ -96,6 +97,8 @@ namespace NActors {
         THashMap<ui32, TInstant> LastLogNotice;
         const TDuration MuteDuration = TDuration::Seconds(15);
         TInstant Deadline;
+        TActorId HandshakeBroker;
+        std::optional<TBrokerLeaseHolder> BrokerLeaseHolder;
 
     public:
         THandshakeActor(TInterconnectProxyCommon::TPtr common, const TActorId& self, const TActorId& peer,
@@ -113,6 +116,7 @@ namespace NActors {
             Y_VERIFY(SelfVirtualId);
             Y_VERIFY(SelfVirtualId.NodeId());
             Y_VERIFY(PeerNodeId);
+            HandshakeBroker = MakeHandshakeBrokerOutId();
         }
 
         THandshakeActor(TInterconnectProxyCommon::TPtr common, TSocketPtr socket)
@@ -135,14 +139,42 @@ namespace NActors {
         }
 
         void Run() override {
+            try {
+                RunImpl();
+            } catch (const TDtorException&) {
+                if (BrokerLeaseHolder) {
+                    BrokerLeaseHolder->ForgetLease();
+                }
+                throw;
+            } catch (...) {
+                throw;
+            }
+        }
+
+        void RunImpl() {
             UpdatePrefix();
 
+            if (!Socket && Common->OutgoingHandshakeInflightLimit) {
+                // Create holder, which sends request to broker and automatically frees the place when destroyed
+                BrokerLeaseHolder.emplace(GetActorSystem(), SelfActorId, HandshakeBroker);
+            }
+
+            if (BrokerLeaseHolder && BrokerLeaseHolder->IsLeaseRequested()) {
+                WaitForSpecificEvent<TEvHandshakeBrokerPermit>("HandshakeBrokerPermit");
+            }
+
             // set up overall handshake process timer
             TDuration timeout = Common->Settings.Handshake;
             if (timeout == TDuration::Zero()) {
                 timeout = DEFAULT_HANDSHAKE_TIMEOUT;
             }
             timeout += ResolveTimeout * 2;
+
+            if (Socket) {
+                // Incoming handshakes have shorter timeout than outgoing
+                timeout *= 0.9;
+            }
+
             Deadline = Now() + timeout;
             Schedule(Deadline, new TEvents::TEvWakeup);
 
@@ -176,6 +208,7 @@ namespace NActors {
                     *NextPacketFromPeer, ProgramInfo->Release(), std::move(Params)));
             }
 
+            BrokerLeaseHolder.reset();
             Socket.Reset();
         }
 
@@ -850,7 +883,7 @@ namespace NActors {
                 addresses.emplace_back(r.GetAddress(), static_cast<ui16>(r.GetPort()));
             } else {
                 Y_VERIFY(ev->GetTypeRewrite() == ui32(ENetwork::ResolveError));
-                Fail(TEvHandshakeFail::HANDSHAKE_FAIL_PERMANENT, "DNS resolve error: " + ev->Get<TEvResolveError>()->Explain 
+                Fail(TEvHandshakeFail::HANDSHAKE_FAIL_PERMANENT, "DNS resolve error: " + ev->Get<TEvResolveError>()->Explain
                     + ", Unresolved host# " + ev->Get<TEvResolveError>()->Host, true);
             }
 
diff --git a/library/cpp/actors/interconnect/interconnect_handshake.h b/library/cpp/actors/interconnect/interconnect_handshake.h
index b3c0db6c5d..fc37f11251 100644
--- a/library/cpp/actors/interconnect/interconnect_handshake.h
+++ b/library/cpp/actors/interconnect/interconnect_handshake.h
@@ -10,7 +10,7 @@
 #include "events_local.h"
 
 namespace NActors {
-    static constexpr TDuration DEFAULT_HANDSHAKE_TIMEOUT = TDuration::Seconds(1);
+    static constexpr TDuration DEFAULT_HANDSHAKE_TIMEOUT = TDuration::Seconds(5);
     static constexpr ui64 INTERCONNECT_PROTOCOL_VERSION = 2;
 
     using TSocketPtr = TIntrusivePtr<NInterconnect::TStreamSocket>;
diff --git a/library/cpp/actors/interconnect/interconnect_tcp_server.cpp b/library/cpp/actors/interconnect/interconnect_tcp_server.cpp
index aad8677ca4..ede35b0b8b 100644
--- a/library/cpp/actors/interconnect/interconnect_tcp_server.cpp
+++ b/library/cpp/actors/interconnect/interconnect_tcp_server.cpp
@@ -46,9 +46,10 @@ namespace NActors {
             if (addr.GetFamily() == AF_INET6) {
                 SetSockOpt(*Listener, IPPROTO_IPV6, IPV6_V6ONLY, 0);
             }
+            const ui32 backlog = ProxyCommonCtx->Settings.SocketBacklogSize;
             if (const auto e = -Listener->Bind(addr)) {
                 return e;
-            } else if (const auto e = -Listener->Listen(SOMAXCONN)) {
+            } else if (const auto e = -Listener->Listen(backlog ? backlog : SOMAXCONN)) {
                 return e;
             } else {
                 return 0;
diff --git a/library/cpp/actors/interconnect/ut/lib/ic_test_cluster.h b/library/cpp/actors/interconnect/ut/lib/ic_test_cluster.h
index 2b6d27cd3f..dd2557e25e 100644
--- a/library/cpp/actors/interconnect/ut/lib/ic_test_cluster.h
+++ b/library/cpp/actors/interconnect/ut/lib/ic_test_cluster.h
@@ -26,13 +26,15 @@ private:
     TList<TTrafficInterrupter> interrupters;
     NActors::TChannelsConfig ChannelsConfig;
     TPortManager PortManager;
+    TIntrusivePtr<NLog::TSettings> LoggerSettings;
 
 public:
     TTestICCluster(ui32 numNodes = 1, NActors::TChannelsConfig channelsConfig = NActors::TChannelsConfig(),
-                   TTrafficInterrupterSettings* tiSettings = nullptr)
+                   TTrafficInterrupterSettings* tiSettings = nullptr, TIntrusivePtr<NLog::TSettings> loggerSettings = nullptr)
         : NumNodes(numNodes)
         , Counters(new NMonitoring::TDynamicCounters)
         , ChannelsConfig(channelsConfig)
+        , LoggerSettings(loggerSettings)
     {
         THashMap<ui32, ui16> nodeToPortMap;
         THashMap<ui32, THashMap<ui32, ui16>> specificNodePortMap;
@@ -59,7 +61,8 @@ public:
 
         for (ui32 i = 1; i <= NumNodes; ++i) {
             auto& portMap = tiSettings ? specificNodePortMap[i] : nodeToPortMap;
-            Nodes.emplace(i, MakeHolder<TNode>(i, NumNodes, portMap, Address, Counters, DeadPeerTimeout, ChannelsConfig));
+            Nodes.emplace(i, MakeHolder<TNode>(i, NumNodes, portMap, Address, Counters, DeadPeerTimeout, ChannelsConfig,
+                /*numDynamicNodes=*/0, /*numThreads=*/1, LoggerSettings));
         }
     }
 
diff --git a/library/cpp/actors/interconnect/ut/lib/node.h b/library/cpp/actors/interconnect/ut/lib/node.h
index ff30b1445e..0b538cdb1c 100644
--- a/library/cpp/actors/interconnect/ut/lib/node.h
+++ b/library/cpp/actors/interconnect/ut/lib/node.h
@@ -6,6 +6,7 @@
 #include <library/cpp/actors/core/mailbox.h>
 #include <library/cpp/actors/dnsresolver/dnsresolver.h>
 
+#include <library/cpp/actors/interconnect/handshake_broker.h>
 #include <library/cpp/actors/interconnect/interconnect_tcp_server.h>
 #include <library/cpp/actors/interconnect/interconnect_tcp_proxy.h>
 #include <library/cpp/actors/interconnect/interconnect_proxy_wrapper.h>
@@ -19,7 +20,8 @@ public:
     TNode(ui32 nodeId, ui32 numNodes, const THashMap<ui32, ui16>& nodeToPort, const TString& address,
           NMonitoring::TDynamicCounterPtr counters, TDuration deadPeerTimeout,
           TChannelsConfig channelsSettings = TChannelsConfig(),
-          ui32 numDynamicNodes = 0, ui32 numThreads = 1) {
+          ui32 numDynamicNodes = 0, ui32 numThreads = 1,
+          TIntrusivePtr<NLog::TSettings> loggerSettings = nullptr) {
         TActorSystemSetup setup;
         setup.NodeId = nodeId;
         setup.ExecutorsCount = 1;
@@ -43,6 +45,7 @@ public:
         common->Settings.SendBufferDieLimitInMB = 512;
         common->Settings.TotalInflightAmountOfData = 512 * 1024;
         common->Settings.TCPSocketBufferSize = 2048 * 1024;
+        common->OutgoingHandshakeInflightLimit = 3;
 
         setup.Interconnect.ProxyActors.resize(numNodes + 1 - numDynamicNodes);
         setup.Interconnect.ProxyWrapperFactory = CreateProxyWrapperFactory(common, interconnectPoolId);
@@ -62,29 +65,31 @@ public:
         setup.LocalServices.emplace_back(MakePollerActorId(), TActorSetupCmd(CreatePollerActor(),
             TMailboxType::ReadAsFilled, 0));
 
-        const TActorId loggerActorId(0, "logger");
-        constexpr ui32 LoggerComponentId = 410; // NKikimrServices::LOGGER
-
-        auto loggerSettings = MakeIntrusive<NLog::TSettings>(
-            loggerActorId,
-            (NLog::EComponent)LoggerComponentId,
-            NLog::PRI_INFO,
-            NLog::PRI_DEBUG,
-            0U);
-
-        loggerSettings->Append(
-            NActorsServices::EServiceCommon_MIN,
-            NActorsServices::EServiceCommon_MAX,
-            NActorsServices::EServiceCommon_Name
-        );
-
-        constexpr ui32 WilsonComponentId = 430; // NKikimrServices::WILSON
-        static const TString WilsonComponentName = "WILSON";
-
-        loggerSettings->Append(
-            (NLog::EComponent)WilsonComponentId,
-            (NLog::EComponent)WilsonComponentId + 1,
-            [](NLog::EComponent) -> const TString & { return WilsonComponentName; });
+        const TActorId loggerActorId = loggerSettings ? loggerSettings->LoggerActorId : TActorId(0, "logger");
+
+        if (!loggerSettings) {
+            constexpr ui32 LoggerComponentId = 410; // NKikimrServices::LOGGER
+            loggerSettings = MakeIntrusive<NLog::TSettings>(
+                loggerActorId,
+                (NLog::EComponent)LoggerComponentId,
+                NLog::PRI_INFO,
+                NLog::PRI_DEBUG,
+                0U);
+
+            loggerSettings->Append(
+                NActorsServices::EServiceCommon_MIN,
+                NActorsServices::EServiceCommon_MAX,
+                NActorsServices::EServiceCommon_Name
+            );
+
+            constexpr ui32 WilsonComponentId = 430; // NKikimrServices::WILSON
+            static const TString WilsonComponentName = "WILSON";
+
+            loggerSettings->Append(
+                (NLog::EComponent)WilsonComponentId,
+                (NLog::EComponent)WilsonComponentId + 1,
+                [](NLog::EComponent) -> const TString & { return WilsonComponentName; });
+        }
 
         // register nameserver table
         auto names = MakeIntrusive<TTableNameserverSetup>();
@@ -105,6 +110,14 @@ public:
             CreateStderrBackend(), counters->GetSubgroup("subsystem", "logger")),
             TMailboxType::ReadAsFilled, interconnectPoolId));
 
+
+        if (common->OutgoingHandshakeInflightLimit) {
+            // create handshake broker actor
+            setup.LocalServices.emplace_back(MakeHandshakeBrokerOutId(), TActorSetupCmd(
+                    CreateHandshakeBroker(*common->OutgoingHandshakeInflightLimit),
+                    TMailboxType::ReadAsFilled, interconnectPoolId));
+        }
+
         auto sp = MakeHolder<TActorSystemSetup>(std::move(setup));
         ActorSystem.Reset(new TActorSystem(sp, nullptr, loggerSettings));
         ActorSystem->Start();
diff --git a/library/cpp/actors/interconnect/ut/lib/test_events.h b/library/cpp/actors/interconnect/ut/lib/test_events.h
index cd0d9e0152..1bb5eb7d38 100644
--- a/library/cpp/actors/interconnect/ut/lib/test_events.h
+++ b/library/cpp/actors/interconnect/ut/lib/test_events.h
@@ -9,6 +9,7 @@ namespace NActors {
         EvTestSmall,
         EvTestLarge,
         EvTestResponse,
+        EvTestStartPolling,
     };
 
     struct TEvTest : TEventPB<TEvTest, NInterconnectTest::TEvTest, EvTest> {
@@ -46,4 +47,8 @@ namespace NActors {
         }
     };
 
+    struct TEvTestStartPolling : TEventPB<TEvTestStartPolling, NInterconnectTest::TEvTestStartPolling, EvTestStartPolling> {
+        TEvTestStartPolling() = default;
+    };
+
 }
diff --git a/library/cpp/actors/interconnect/ut/protos/interconnect_test.proto b/library/cpp/actors/interconnect/ut/protos/interconnect_test.proto
index b9b2bd6a4e..b74d068a8b 100644
--- a/library/cpp/actors/interconnect/ut/protos/interconnect_test.proto
+++ b/library/cpp/actors/interconnect/ut/protos/interconnect_test.proto
@@ -23,3 +23,6 @@ message TEvTestSmall {
 message TEvTestResponse {
     optional uint64 ConfirmedSequenceNumber = 1;
 }
+
+message TEvTestStartPolling {
+}
diff --git a/library/cpp/actors/interconnect/ut_huge_cluster/CMakeLists.darwin.txt b/library/cpp/actors/interconnect/ut_huge_cluster/CMakeLists.darwin.txt
new file mode 100644
index 0000000000..89c38824c2
--- /dev/null
+++ b/library/cpp/actors/interconnect/ut_huge_cluster/CMakeLists.darwin.txt
@@ -0,0 +1,45 @@
+
+# This file was gererated 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(library-cpp-actors-interconnect-ut_huge_cluster)
+target_link_libraries(library-cpp-actors-interconnect-ut_huge_cluster PUBLIC
+  contrib-libs-cxxsupp
+  yutil
+  library-cpp-cpuid_check
+  cpp-testing-unittest_main
+  cpp-actors-core
+  cpp-actors-interconnect
+  interconnect-ut-lib
+  interconnect-ut-protos
+  cpp-testing-unittest
+  cpp-actors-testlib
+)
+target_link_options(library-cpp-actors-interconnect-ut_huge_cluster PRIVATE
+  -Wl,-no_deduplicate
+  -Wl,-sdk_version,10.15
+  -fPIC
+  -fPIC
+  -framework
+  CoreFoundation
+)
+target_sources(library-cpp-actors-interconnect-ut_huge_cluster PRIVATE
+  ${CMAKE_SOURCE_DIR}/library/cpp/actors/interconnect/ut_huge_cluster/huge_cluster.cpp
+)
+add_test(
+  NAME
+  library-cpp-actors-interconnect-ut_huge_cluster
+  COMMAND
+  library-cpp-actors-interconnect-ut_huge_cluster
+  --print-before-suite
+  --print-before-test
+  --fork-tests
+  --print-times
+  --show-fails
+)
+vcs_info(library-cpp-actors-interconnect-ut_huge_cluster)
diff --git a/library/cpp/actors/interconnect/ut_huge_cluster/CMakeLists.linux-aarch64.txt b/library/cpp/actors/interconnect/ut_huge_cluster/CMakeLists.linux-aarch64.txt
new file mode 100644
index 0000000000..33064b5008
--- /dev/null
+++ b/library/cpp/actors/interconnect/ut_huge_cluster/CMakeLists.linux-aarch64.txt
@@ -0,0 +1,48 @@
+
+# This file was gererated 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(library-cpp-actors-interconnect-ut_huge_cluster)
+target_link_libraries(library-cpp-actors-interconnect-ut_huge_cluster PUBLIC
+  contrib-libs-linux-headers
+  contrib-libs-cxxsupp
+  yutil
+  library-cpp-lfalloc
+  cpp-testing-unittest_main
+  cpp-actors-core
+  cpp-actors-interconnect
+  interconnect-ut-lib
+  interconnect-ut-protos
+  cpp-testing-unittest
+  cpp-actors-testlib
+)
+target_link_options(library-cpp-actors-interconnect-ut_huge_cluster PRIVATE
+  -ldl
+  -lrt
+  -Wl,--no-as-needed
+  -fPIC
+  -fPIC
+  -lpthread
+  -lrt
+  -ldl
+)
+target_sources(library-cpp-actors-interconnect-ut_huge_cluster PRIVATE
+  ${CMAKE_SOURCE_DIR}/library/cpp/actors/interconnect/ut_huge_cluster/huge_cluster.cpp
+)
+add_test(
+  NAME
+  library-cpp-actors-interconnect-ut_huge_cluster
+  COMMAND
+  library-cpp-actors-interconnect-ut_huge_cluster
+  --print-before-suite
+  --print-before-test
+  --fork-tests
+  --print-times
+  --show-fails
+)
+vcs_info(library-cpp-actors-interconnect-ut_huge_cluster)
diff --git a/library/cpp/actors/interconnect/ut_huge_cluster/CMakeLists.linux.txt b/library/cpp/actors/interconnect/ut_huge_cluster/CMakeLists.linux.txt
new file mode 100644
index 0000000000..5b08a947cf
--- /dev/null
+++ b/library/cpp/actors/interconnect/ut_huge_cluster/CMakeLists.linux.txt
@@ -0,0 +1,50 @@
+
+# This file was gererated 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(library-cpp-actors-interconnect-ut_huge_cluster)
+target_link_libraries(library-cpp-actors-interconnect-ut_huge_cluster 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
+  cpp-actors-core
+  cpp-actors-interconnect
+  interconnect-ut-lib
+  interconnect-ut-protos
+  cpp-testing-unittest
+  cpp-actors-testlib
+)
+target_link_options(library-cpp-actors-interconnect-ut_huge_cluster PRIVATE
+  -ldl
+  -lrt
+  -Wl,--no-as-needed
+  -fPIC
+  -fPIC
+  -lpthread
+  -lrt
+  -ldl
+)
+target_sources(library-cpp-actors-interconnect-ut_huge_cluster PRIVATE
+  ${CMAKE_SOURCE_DIR}/library/cpp/actors/interconnect/ut_huge_cluster/huge_cluster.cpp
+)
+add_test(
+  NAME
+  library-cpp-actors-interconnect-ut_huge_cluster
+  COMMAND
+  library-cpp-actors-interconnect-ut_huge_cluster
+  --print-before-suite
+  --print-before-test
+  --fork-tests
+  --print-times
+  --show-fails
+)
+vcs_info(library-cpp-actors-interconnect-ut_huge_cluster)
diff --git a/library/cpp/actors/interconnect/ut_huge_cluster/CMakeLists.txt b/library/cpp/actors/interconnect/ut_huge_cluster/CMakeLists.txt
new file mode 100644
index 0000000000..3e0811fb22
--- /dev/null
+++ b/library/cpp/actors/interconnect/ut_huge_cluster/CMakeLists.txt
@@ -0,0 +1,15 @@
+
+# This file was gererated 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)
+  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/library/cpp/actors/interconnect/ut_huge_cluster/huge_cluster.cpp b/library/cpp/actors/interconnect/ut_huge_cluster/huge_cluster.cpp
new file mode 100644
index 0000000000..458ead3459
--- /dev/null
+++ b/library/cpp/actors/interconnect/ut_huge_cluster/huge_cluster.cpp
@@ -0,0 +1,167 @@
+#include <library/cpp/actors/interconnect/ut/lib/ic_test_cluster.h>
+#include <library/cpp/actors/interconnect/ut/lib/test_events.h>
+#include <library/cpp/actors/interconnect/ut/lib/test_actors.h>
+
+#include <library/cpp/testing/unittest/registar.h>
+
+#include <vector>
+
+Y_UNIT_TEST_SUITE(HugeCluster) {
+    using namespace NActors;
+
+    class TPoller: public TActor<TPoller> {
+        const std::vector<TActorId>& Targets;
+        std::unordered_map<TActorId, TManualEvent>& Connected;
+
+    public:
+        TPoller(const std::vector<TActorId>& targets, std::unordered_map<TActorId, TManualEvent>& events)
+            : TActor(&TPoller::StateFunc)
+            , Targets(targets)
+            , Connected(events)
+        {}
+
+        void Handle(TEvTestStartPolling::TPtr /*ev*/, const TActorContext& ctx) {
+            for (ui32 i = 0; i < Targets.size(); ++i) {
+                ctx.Send(Targets[i], new TEvTest(), IEventHandle::FlagTrackDelivery, i);
+            }
+        }
+
+        void Handle(TEvents::TEvUndelivered::TPtr ev, const TActorContext& ctx) {
+            const ui32 cookie = ev->Cookie;
+            // Cerr << "TEvUndelivered ping from node# " << SelfId().NodeId() << " to node# " << cookie + 1 << Endl;
+            ctx.Send(Targets[cookie], new TEvTest(), IEventHandle::FlagTrackDelivery, cookie);
+        }
+
+        void Handle(TEvTest::TPtr ev, const TActorContext& /*ctx*/) {
+            // Cerr << "Polled from " << ev->Sender.ToString() << Endl;
+            Connected[ev->Sender].Signal();
+        }
+
+        void Handle(TEvents::TEvPoisonPill::TPtr& /*ev*/, const TActorContext& ctx) {
+            Die(ctx);
+        }
+
+        STRICT_STFUNC(StateFunc,
+            HFunc(TEvents::TEvUndelivered, Handle)
+            HFunc(TEvTestStartPolling, Handle)
+            HFunc(TEvTest, Handle)
+            HFunc(TEvents::TEvPoisonPill, Handle)
+        )
+    };
+
+    class TStartPollers : public TActorBootstrapped<TStartPollers> {
+        const std::vector<TActorId>& Pollers;
+
+    public:
+        TStartPollers(const std::vector<TActorId>& pollers)
+            : Pollers(pollers)
+        {}
+
+        void Bootstrap(const TActorContext& ctx) {
+            Become(&TThis::StateFunc);
+            for (ui32 i = 0; i < Pollers.size(); ++i) {
+                ctx.Send(Pollers[i], new TEvTestStartPolling(), IEventHandle::FlagTrackDelivery, i);
+            }
+        }
+
+        void Handle(TEvents::TEvUndelivered::TPtr ev, const TActorContext& ctx) {
+            const ui32 cookie = ev->Cookie;
+            // Cerr << "TEvUndelivered start poller message to node# " << cookie + 1 << Endl;
+            ctx.Send(Pollers[cookie], new TEvTestStartPolling(), IEventHandle::FlagTrackDelivery, cookie);
+        }
+
+        void Handle(TEvents::TEvPoisonPill::TPtr& /*ev*/, const TActorContext& ctx) {
+            Die(ctx);
+        }
+
+        STRICT_STFUNC(StateFunc,
+            HFunc(TEvents::TEvUndelivered, Handle)
+            HFunc(TEvents::TEvPoisonPill, Handle)
+        )
+    };
+
+    TIntrusivePtr<NLog::TSettings> MakeLogConfigs(NLog::EPriority priority) {
+        // custom logger settings
+        auto loggerSettings = MakeIntrusive<NLog::TSettings>(
+                TActorId(0, "logger"),
+                (NLog::EComponent)410,
+                priority,
+                priority,
+                0U);
+
+        loggerSettings->Append(
+            NActorsServices::EServiceCommon_MIN,
+            NActorsServices::EServiceCommon_MAX,
+            NActorsServices::EServiceCommon_Name
+        );
+
+        constexpr ui32 WilsonComponentId = 430; // NKikimrServices::WILSON
+        static const TString WilsonComponentName = "WILSON";
+
+        loggerSettings->Append(
+            (NLog::EComponent)WilsonComponentId,
+            (NLog::EComponent)WilsonComponentId + 1,
+            [](NLog::EComponent) -> const TString & { return WilsonComponentName; });
+
+        return loggerSettings;
+    }
+
+    Y_UNIT_TEST(AllToAll) {
+        ui32 nodesNum = 120;
+        std::vector<TActorId> pollers(nodesNum);
+        std::vector<std::unordered_map<TActorId, TManualEvent>> events(nodesNum);
+
+        // Must destroy actor system before shared arrays
+        {
+            TTestICCluster testCluster(nodesNum, NActors::TChannelsConfig(), nullptr, MakeLogConfigs(NLog::PRI_EMERG));
+
+            for (ui32 i = 0; i < nodesNum; ++i) {
+                pollers[i] = testCluster.RegisterActor(new TPoller(pollers, events[i]), i + 1);
+            }
+
+            for (ui32 i = 0; i < nodesNum; ++i) {
+                for (const auto& actor : pollers) {
+                    events[i][actor] = TManualEvent();
+                }
+            }
+
+            testCluster.RegisterActor(new TStartPollers(pollers), 1);
+
+            for (ui32 i = 0; i < nodesNum; ++i) {
+                for (auto& [_, ev] : events[i]) {
+                    ev.WaitI();
+                }
+            }
+        }
+    }
+
+
+    Y_UNIT_TEST(AllToOne) {
+        ui32 nodesNum = 500;
+        std::vector<TActorId> listeners;
+        std::vector<TActorId> pollers(nodesNum - 1);
+        std::unordered_map<TActorId, TManualEvent> events;
+        std::unordered_map<TActorId, TManualEvent> emptyEventList;
+
+        // Must destroy actor system before shared arrays
+        {
+            TTestICCluster testCluster(nodesNum, NActors::TChannelsConfig(), nullptr, MakeLogConfigs(NLog::PRI_EMERG));
+
+            const TActorId listener = testCluster.RegisterActor(new TPoller({}, events), nodesNum);
+            listeners = { listener };
+            for (ui32 i = 0; i < nodesNum - 1; ++i) {
+                pollers[i] = testCluster.RegisterActor(new TPoller(listeners, emptyEventList), i + 1);
+            }
+
+            for (const auto& actor : pollers) {
+                events[actor] = TManualEvent();
+            }
+
+            testCluster.RegisterActor(new TStartPollers(pollers), 1);
+
+            for (auto& [_, ev] : events) {
+                ev.WaitI();
+            }
+        }
+    }
+}
diff --git a/library/cpp/actors/util/rc_buf.h b/library/cpp/actors/util/rc_buf.h
index a2bce33fba..5d4517ade2 100644
--- a/library/cpp/actors/util/rc_buf.h
+++ b/library/cpp/actors/util/rc_buf.h
@@ -306,9 +306,12 @@ class TRcBuf {
 
         struct TBackendHolder {
             uintptr_t Data[2];
-            operator bool() const noexcept {
+            explicit operator bool() const noexcept {
                 return Data[0] || Data[1];
             }
+            friend bool operator ==(const TBackendHolder& x, const TBackendHolder& y) {
+                return x.Data[0] == y.Data[0] && x.Data[1] == y.Data[1];
+            }
         };
 
         constexpr static TBackendHolder Empty = {0, 0};
@@ -592,7 +595,7 @@ class TRcBuf {
         }
 
         explicit operator bool() const {
-            return Owner;
+            return static_cast<bool>(Owner);
         }
 
     private:
diff --git a/library/cpp/monlib/service/pages/index_mon_page.cpp b/library/cpp/monlib/service/pages/index_mon_page.cpp
index 2bfa0faca8..c9b2f82cc0 100644
--- a/library/cpp/monlib/service/pages/index_mon_page.cpp
+++ b/library/cpp/monlib/service/pages/index_mon_page.cpp
@@ -28,9 +28,8 @@ void TIndexMonPage::Output(IMonHttpRequest& request) {
         TGuard<TMutex> g(Mtx);
         TStringBuf pathTmp = request.GetPathInfo();
         for (;;) {
-            TPagesByPath::iterator i = PagesByPath.find(pathTmp);
-            if (i != PagesByPath.end()) {
-                found = i->second;
+            if (TPagesByPath::iterator i = PagesByPath.find(pathTmp); i != PagesByPath.end()) {
+                found = *i->second;
                 pathInfo = request.GetPathInfo().substr(pathTmp.size());
                 Y_VERIFY(pathInfo.empty() || pathInfo.StartsWith('/'));
                 break;
@@ -67,18 +66,12 @@ void TIndexMonPage::OutputIndex(IOutputStream& out, bool pathEndsWithSlash) {
 
 void TIndexMonPage::Register(TMonPagePtr page) {
     TGuard<TMutex> g(Mtx);
-    auto insres = PagesByPath.insert(std::make_pair("/" + page->GetPath(), page));
-    if (insres.second) {
-        // new unique page just inserted, update Pages
-        Pages.push_back(page);
+    if (auto [it, inserted] = PagesByPath.try_emplace("/" + page->GetPath()); inserted) {
+        // new unique page just inserted, insert it to the end
+        it->second = Pages.insert(Pages.end(), page);
     } else {
         // a page with the given path is already present, replace it with the new page
-
-        // find old page, sorry for O(n)
-        auto it = std::find(Pages.begin(), Pages.end(), insres.first->second);
-        *it = page;
-        // this already present, replace it
-        insres.first->second = page;
+        *it->second = page;
     }
     page->Parent = this;
 }
@@ -101,7 +94,7 @@ IMonPage* TIndexMonPage::FindPage(const TString& relativePath) {
     if (i == PagesByPath.end()) {
         return nullptr;
     } else {
-        return i->second.Get();
+        return i->second->Get();
     }
 }
 
@@ -171,7 +164,7 @@ void TIndexMonPage::OutputBody(IMonHttpRequest& req) {
 
 void TIndexMonPage::SortPages() {
     TGuard<TMutex> g(Mtx);
-    std::sort(Pages.begin(), Pages.end(), [](const TMonPagePtr& a, const TMonPagePtr& b) {
+    Pages.sort([](const TMonPagePtr& a, const TMonPagePtr& b) {
         return AsciiCompareIgnoreCase(a->GetTitle(), b->GetTitle()) < 0;
     });
 }
diff --git a/library/cpp/monlib/service/pages/index_mon_page.h b/library/cpp/monlib/service/pages/index_mon_page.h
index af96bcd2b9..0aaf826d46 100644
--- a/library/cpp/monlib/service/pages/index_mon_page.h
+++ b/library/cpp/monlib/service/pages/index_mon_page.h
@@ -2,12 +2,14 @@
 
 #include "mon_page.h"
 
+#include <list>
+
 namespace NMonitoring {
     struct TIndexMonPage: public IMonPage {
         TMutex Mtx;
-        typedef TVector<TMonPagePtr> TPages;
-        TPages Pages;
-        typedef THashMap<TString, TMonPagePtr> TPagesByPath;
+        using TPages = std::list<TMonPagePtr>;
+        TPages Pages; // a list of pages to maintain specific order
+        using TPagesByPath = THashMap<TString, TPages::iterator>;
         TPagesByPath PagesByPath;
 
         TIndexMonPage(const TString& path, const TString& title)
diff --git a/library/cpp/threading/CMakeLists.txt b/library/cpp/threading/CMakeLists.txt
index 1246829e67..6a92c755cd 100644
--- a/library/cpp/threading/CMakeLists.txt
+++ b/library/cpp/threading/CMakeLists.txt
@@ -10,6 +10,7 @@ add_subdirectory(atomic)
 add_subdirectory(chunk_queue)
 add_subdirectory(equeue)
 add_subdirectory(future)
+add_subdirectory(hot_swap)
 add_subdirectory(light_rw_lock)
 add_subdirectory(local_executor)
 add_subdirectory(poor_man_openmp)
diff --git a/library/cpp/threading/hot_swap/CMakeLists.darwin.txt b/library/cpp/threading/hot_swap/CMakeLists.darwin.txt
new file mode 100644
index 0000000000..fb3d6d7710
--- /dev/null
+++ b/library/cpp/threading/hot_swap/CMakeLists.darwin.txt
@@ -0,0 +1,18 @@
+
+# This file was gererated 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_library(cpp-threading-hot_swap)
+target_link_libraries(cpp-threading-hot_swap PUBLIC
+  contrib-libs-cxxsupp
+  yutil
+  cpp-deprecated-atomic
+)
+target_sources(cpp-threading-hot_swap PRIVATE
+  ${CMAKE_SOURCE_DIR}/library/cpp/threading/hot_swap/hot_swap.cpp
+)
diff --git a/library/cpp/threading/hot_swap/CMakeLists.linux-aarch64.txt b/library/cpp/threading/hot_swap/CMakeLists.linux-aarch64.txt
new file mode 100644
index 0000000000..48692e2319
--- /dev/null
+++ b/library/cpp/threading/hot_swap/CMakeLists.linux-aarch64.txt
@@ -0,0 +1,19 @@
+
+# This file was gererated 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_library(cpp-threading-hot_swap)
+target_link_libraries(cpp-threading-hot_swap PUBLIC
+  contrib-libs-linux-headers
+  contrib-libs-cxxsupp
+  yutil
+  cpp-deprecated-atomic
+)
+target_sources(cpp-threading-hot_swap PRIVATE
+  ${CMAKE_SOURCE_DIR}/library/cpp/threading/hot_swap/hot_swap.cpp
+)
diff --git a/library/cpp/threading/hot_swap/CMakeLists.linux.txt b/library/cpp/threading/hot_swap/CMakeLists.linux.txt
new file mode 100644
index 0000000000..48692e2319
--- /dev/null
+++ b/library/cpp/threading/hot_swap/CMakeLists.linux.txt
@@ -0,0 +1,19 @@
+
+# This file was gererated 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_library(cpp-threading-hot_swap)
+target_link_libraries(cpp-threading-hot_swap PUBLIC
+  contrib-libs-linux-headers
+  contrib-libs-cxxsupp
+  yutil
+  cpp-deprecated-atomic
+)
+target_sources(cpp-threading-hot_swap PRIVATE
+  ${CMAKE_SOURCE_DIR}/library/cpp/threading/hot_swap/hot_swap.cpp
+)
diff --git a/library/cpp/threading/hot_swap/CMakeLists.txt b/library/cpp/threading/hot_swap/CMakeLists.txt
new file mode 100644
index 0000000000..3e0811fb22
--- /dev/null
+++ b/library/cpp/threading/hot_swap/CMakeLists.txt
@@ -0,0 +1,15 @@
+
+# This file was gererated 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)
+  include(CMakeLists.darwin.txt)
+elseif (CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64" AND UNIX AND NOT APPLE AND NOT ANDROID)
+  include(CMakeLists.linux.txt)
+endif()