Revert commit rXXXXXX

5 files changed, 123 insertions, 112 deletions

diff --git a/ydb/core/kqp/kqp_session_actor.cpp b/ydb/core/kqp/kqp_session_actor.cpp
index b73175be91..b6ee60731a 100644
--- a/ydb/core/kqp/kqp_session_actor.cpp
+++ b/ydb/core/kqp/kqp_session_actor.cpp
@@ -177,6 +177,7 @@ public:
         Config->FeatureFlags = AppData()->FeatureFlags;
 
         Become(&TKqpSessionActor::ReadyState);
+        StartIdleTimer();
     }
 
     NYql::TKikimrQueryDeadlines GetQueryDeadlines(const NKikimrKqp::TQueryRequest& queryRequest) {
@@ -416,6 +417,8 @@ public:
                 return;
         }
 
+        StopIdleTimer();
+
         CompileQuery();
     }
 
@@ -1754,6 +1757,8 @@ public:
             ? Ydb::Table::KeepAliveResult::SESSION_STATUS_READY
             : Ydb::Table::KeepAliveResult::SESSION_STATUS_BUSY;
         record.MutableResponse()->SetSessionStatus(sessionStatus);
+        StartIdleTimer();
+
         Send(ev->Sender, result.release(), 0, proxyRequestId);
     }
 
@@ -1808,6 +1813,35 @@ public:
         }
     }
 
+    void StartIdleTimer() {
+        StopIdleTimer();
+
+        ++IdleTimerId;
+        auto idleDuration = TDuration::Seconds(*Config->_KqpSessionIdleTimeoutSec.Get());
+        IdleTimerActorId = CreateLongTimer(TlsActivationContext->AsActorContext(), idleDuration,
+                new IEventHandle(SelfId(), SelfId(), new TEvKqp::TEvIdleTimeout(IdleTimerId)));
+        LOG_D("Created long timer for idle timeout, timer id: " << IdleTimerId
+                << ", duration: " << idleDuration << ", actor: " << IdleTimerActorId);
+    }
+
+    void StopIdleTimer() {
+        if (IdleTimerActorId) {
+            LOG_D("Destroying long timer actor for idle timout: " << IdleTimerActorId);
+            Send(IdleTimerActorId, new TEvents::TEvPoisonPill());
+        }
+        IdleTimerActorId = TActorId();
+    }
+
+    void Handle(TEvKqp::TEvIdleTimeout::TPtr& ev) {
+        auto timerId = ev->Get()->TimerId;
+
+        if (timerId == IdleTimerId) {
+            LOG_N(TKqpRequestInfo("", SessionId) << "SessionActor idle timeout, worker destroyed");
+            Counters->ReportSessionActorClosedIdle(Settings.DbCounters);
+            FinalCleanup();
+        }
+    }
+
     void SendRollbackRequest(TKqpTransactionContext* txCtx) {
         if (QueryState) {
             LWTRACK(KqpSessionSendRollback, QueryState->Orbit, QueryState->CurrentTx);
@@ -1953,6 +1987,7 @@ public:
             TransactionsToBeAborted.clear();
             CleanupCtx.reset();
             QueryState.reset();
+            StartIdleTimer();
             Become(&TKqpSessionActor::ReadyState);
         }
     }
@@ -2007,6 +2042,7 @@ public:
                 HFunc(TEvKqp::TEvQueryRequest, HandleReady);
 
                 hFunc(TEvKqp::TEvPingSessionRequest, Handle);
+                hFunc(TEvKqp::TEvIdleTimeout, Handle);
                 hFunc(TEvKqp::TEvCloseSessionRequest, HandleReady);
                 hFunc(TEvKqp::TEvInitiateSessionShutdown, Handle);
                 hFunc(TEvKqp::TEvContinueShutdown, Handle);
@@ -2030,6 +2066,7 @@ public:
                 hFunc(TEvKqp::TEvCloseSessionRequest, HandleCompile);
                 hFunc(TEvKqp::TEvInitiateSessionShutdown, Handle);
                 hFunc(TEvKqp::TEvContinueShutdown, Handle);
+                hFunc(TEvKqp::TEvIdleTimeout, HandleNoop);
             default:
                 UnexpectedEvent("CompileState", ev);
             }
@@ -2057,6 +2094,7 @@ public:
                 hFunc(TEvKqp::TEvCloseSessionRequest, HandleExecute);
                 hFunc(TEvKqp::TEvInitiateSessionShutdown, Handle);
                 hFunc(TEvKqp::TEvContinueShutdown, Handle);
+                hFunc(TEvKqp::TEvIdleTimeout, HandleNoop);
 
                 // always come from WorkerActor
                 hFunc(TEvKqp::TEvQueryResponse, ForwardResponse);
@@ -2083,6 +2121,7 @@ public:
                 hFunc(TEvKqp::TEvCloseSessionRequest, HandleCleanup);
                 hFunc(TEvKqp::TEvInitiateSessionShutdown, Handle);
                 hFunc(TEvKqp::TEvContinueShutdown, Handle);
+                hFunc(TEvKqp::TEvIdleTimeout, HandleNoop);
 
                 // always come from WorkerActor
                 hFunc(TEvKqp::TEvCloseSessionResponse, HandleCleanup);
@@ -2105,6 +2144,7 @@ public:
                 hFunc(TEvKqp::TEvCloseSessionRequest, HandleTopicOps);
                 hFunc(TEvKqp::TEvInitiateSessionShutdown, Handle);
                 hFunc(TEvKqp::TEvContinueShutdown, Handle);
+                hFunc(TEvKqp::TEvIdleTimeout, HandleNoop);
             default:
                 UnexpectedEvent("TopicOpsState", ev);
             }
@@ -2261,6 +2301,9 @@ private:
     std::vector<TIntrusivePtr<TKqpTransactionContext>> TransactionsToBeAborted;
     ui64 EvictedTx = 0;
     std::unique_ptr<TEvKqp::TEvQueryResponse> QueryResponse;
+
+    TActorId IdleTimerActorId;
+    ui32 IdleTimerId = 0;
     std::optional<TSessionShutdownState> ShutdownState;
 
     TULIDGenerator UlidGen;
diff --git a/ydb/core/kqp/kqp_worker_actor.cpp b/ydb/core/kqp/kqp_worker_actor.cpp
index 1e8d50ccb0..9f2dfb521e 100644
--- a/ydb/core/kqp/kqp_worker_actor.cpp
+++ b/ydb/core/kqp/kqp_worker_actor.cpp
@@ -125,6 +125,7 @@ public:
         , Config(MakeIntrusive<TKikimrConfiguration>())
         , CreationTime(TInstant::Now())
         , QueryId(0)
+        , IdleTimerId(0)
         , ShutdownState(std::nullopt)
     {
         Y_VERIFY(ModuleResolverState);
@@ -160,6 +161,7 @@ public:
             AppData(ctx)->FunctionRegistry, !Settings.LongSession);
 
         Become(&TKqpWorkerActor::ReadyState);
+        StartIdleTimer(ctx);
     }
 
     void HandleReady(TEvKqp::TEvCloseSessionRequest::TPtr &ev, const TActorContext &ctx) {
@@ -188,6 +190,8 @@ public:
             return;
         }
 
+        StartIdleTimer(ctx);
+
         ReplyPingStatus(ev->Sender, proxyRequestId, true, ctx);
     }
 
@@ -377,6 +381,8 @@ public:
             // some kind of internal query? or verify here?
         }
 
+        StopIdleTimer(ctx);
+
         if (CompileQuery(ctx)) {
             if (QueryState) {
                 QueryState->CpuTime += timer.GetTime();
@@ -405,6 +411,19 @@ public:
         }
     }
 
+    void HandleReady(TEvKqp::TEvIdleTimeout::TPtr &ev, const TActorContext &ctx) {
+        auto timerId = ev->Get()->TimerId;
+        LOG_DEBUG_S(ctx, NKikimrServices::KQP_WORKER, "Received TEvIdleTimeout in ready state, timer id: "
+            << timerId << ", sender: " << ev->Sender);
+
+        if (timerId == IdleTimerId) {
+            LOG_NOTICE_S(ctx, NKikimrServices::KQP_WORKER, TKqpRequestInfo("", SessionId)
+                << "Worker idle timeout, worker destroyed");
+            Counters->ReportWorkerClosedIdle(Settings.DbCounters);
+            FinalCleanup(ctx);
+        }
+    }
+
     void HandleCompileQuery(TEvKqp::TEvCompileResponse::TPtr &ev, const TActorContext &ctx) {
         auto compileResult = ev->Get()->CompileResult;
 
@@ -413,6 +432,7 @@ public:
 
         if (compileResult->Status != Ydb::StatusIds::SUCCESS) {
             if (ReplyQueryCompileError(compileResult, ctx)) {
+                StartIdleTimer(ctx);
                 Become(&TKqpWorkerActor::ReadyState);
             } else {
                 FinalCleanup(ctx);
@@ -435,6 +455,7 @@ public:
 
         if (queryRequest.GetAction() == NKikimrKqp::QUERY_ACTION_PREPARE) {
             if (ReplyPrepareResult(compileResult, ctx)) {
+                StartIdleTimer(ctx);
                 Become(&TKqpWorkerActor::ReadyState);
             } else {
                 FinalCleanup(ctx);
@@ -486,6 +507,11 @@ public:
         ReplyPingStatus(ev->Sender, proxyRequestId, false, ctx);
     }
 
+    void HandleCompileQuery(TEvKqp::TEvIdleTimeout::TPtr &ev, const TActorContext &ctx) {
+        Y_UNUSED(ev);
+        Y_UNUSED(ctx);
+    }
+
     void HandlePerformQuery(TEvKqp::TEvQueryRequest::TPtr &ev, const TActorContext &ctx) {
         ReplyBusy(ev, ctx);
     }
@@ -566,6 +592,11 @@ public:
         }
     }
 
+    void HandlePerformQuery(TEvKqp::TEvIdleTimeout::TPtr &ev, const TActorContext &ctx) {
+        Y_UNUSED(ev);
+        Y_UNUSED(ctx);
+    }
+
     void HandlePerformCleanup(TEvKqp::TEvQueryRequest::TPtr &ev, const TActorContext &ctx) {
         ui64 proxyRequestId = ev->Cookie;
         auto& event = ev->Get()->Record;
@@ -646,6 +677,11 @@ public:
         }
     }
 
+    void HandlePerformCleanup(TEvKqp::TEvIdleTimeout::TPtr &ev, const TActorContext &ctx) {
+        Y_UNUSED(ev);
+        Y_UNUSED(ctx);
+    }
+
     STFUNC(ReadyState) {
         try {
             switch (ev->GetTypeRewrite()) {
@@ -654,6 +690,7 @@ public:
                 HFunc(TEvKqp::TEvCloseSessionRequest, HandleReady);
                 HFunc(TEvKqp::TEvPingSessionRequest, HandleReady);
                 HFunc(TEvKqp::TEvContinueProcess, HandleReady);
+                HFunc(TEvKqp::TEvIdleTimeout, HandleReady);
                 HFunc(TEvKqp::TEvInitiateSessionShutdown, HandleInitiateShutdown);
                 HFunc(TEvKqp::TEvContinueShutdown, HandleContinueShutdown);
             default:
@@ -671,6 +708,7 @@ public:
                 HFunc(TEvKqp::TEvCompileResponse, HandleCompileQuery);
                 HFunc(TEvKqp::TEvCloseSessionRequest, HandleCompileQuery);
                 HFunc(TEvKqp::TEvPingSessionRequest, HandleCompileQuery);
+                HFunc(TEvKqp::TEvIdleTimeout, HandleCompileQuery);
                 HFunc(TEvKqp::TEvInitiateSessionShutdown, HandleInitiateShutdown);
                 HFunc(TEvKqp::TEvContinueShutdown, HandleContinueShutdown);
             default:
@@ -689,6 +727,7 @@ public:
                 HFunc(TEvKqp::TEvCloseSessionRequest, HandlePerformQuery);
                 HFunc(TEvKqp::TEvPingSessionRequest, HandlePerformQuery);
                 HFunc(TEvKqp::TEvContinueProcess, HandlePerformQuery);
+                HFunc(TEvKqp::TEvIdleTimeout, HandlePerformQuery);
                 HFunc(TEvKqp::TEvInitiateSessionShutdown, HandleInitiateShutdown);
                 HFunc(TEvKqp::TEvContinueShutdown, HandleContinueShutdown);
             default:
@@ -707,6 +746,7 @@ public:
                 HFunc(TEvKqp::TEvCloseSessionRequest, HandlePerformCleanup);
                 HFunc(TEvKqp::TEvPingSessionRequest, HandlePerformCleanup);
                 HFunc(TEvKqp::TEvContinueProcess, HandlePerformCleanup);
+                HFunc(TEvKqp::TEvIdleTimeout, HandlePerformCleanup);
                 HFunc(TEvKqp::TEvInitiateSessionShutdown, HandleInitiateShutdown);
                 HFunc(TEvKqp::TEvContinueShutdown, HandleContinueShutdown);
             default:
@@ -1162,6 +1202,7 @@ private:
         CleanupState->Start = TInstant::Now();
 
         if (isFinal) {
+            StopIdleTimer(ctx);
             Counters->ReportQueriesPerWorker(Settings.DbCounters, QueryId);
 
             MakeNewQueryState();
@@ -1210,6 +1251,7 @@ private:
             Die(ctx);
         } else {
             if (ReplyQueryResult(ctx)) {
+                StartIdleTimer(ctx);
                 Become(&TKqpWorkerActor::ReadyState);
             } else {
                 FinalCleanup(ctx);
@@ -2013,6 +2055,26 @@ private:
         }
     }
 
+    void StartIdleTimer(const TActorContext& ctx) {
+        StopIdleTimer(ctx);
+
+        ++IdleTimerId;
+        auto idleDuration = TDuration::Seconds(Config->_KqpSessionIdleTimeoutSec.Get().GetRef());
+        IdleTimerActorId = CreateLongTimer(ctx, idleDuration,
+            new IEventHandle(ctx.SelfID, ctx.SelfID, new TEvKqp::TEvIdleTimeout(IdleTimerId)));
+        LOG_DEBUG_S(ctx, NKikimrServices::KQP_WORKER, "Created long timer for idle timeout, timer id: " << IdleTimerId
+            << ", duration: " << idleDuration << ", actor: " << IdleTimerActorId);
+    }
+
+    void StopIdleTimer(const TActorContext& ctx) {
+        if (IdleTimerActorId) {
+            LOG_DEBUG_S(ctx, NKikimrServices::KQP_WORKER, "Destroying long timer actor for idle timout: "
+                << IdleTimerActorId);
+            ctx.Send(IdleTimerActorId, new TEvents::TEvPoisonPill());
+        }
+        IdleTimerActorId = TActorId();
+    }
+
     IKikimrQueryExecutor::TExecuteSettings CreateRollbackSettings() {
         YQL_ENSURE(QueryState);
 
@@ -2099,6 +2161,8 @@ private:
     ui32 QueryId;
     THolder<TKqpQueryState> QueryState;
     THolder<TKqpCleanupState> CleanupState;
+    ui32 IdleTimerId;
+    TActorId IdleTimerActorId;
     std::optional<TSessionShutdownState> ShutdownState;
 };
 
diff --git a/ydb/core/kqp/proxy/kqp_proxy_service.cpp b/ydb/core/kqp/proxy/kqp_proxy_service.cpp
index ed5356d503..0fb49de196 100644
--- a/ydb/core/kqp/proxy/kqp_proxy_service.cpp
+++ b/ydb/core/kqp/proxy/kqp_proxy_service.cpp
@@ -123,11 +123,11 @@ class TKqpProxyService : public TActorBootstrapped<TKqpProxyService> {
             EvReadyToPublishResources = EventSpaceBegin(TEvents::ES_PRIVATE),
             EvCollectPeerProxyData,
             EvOnRequestTimeout,
-            EvCloseIdleSessions,
         };
 
         struct TEvReadyToPublishResources : public TEventLocal<TEvReadyToPublishResources, EEv::EvReadyToPublishResources> {};
         struct TEvCollectPeerProxyData: public TEventLocal<TEvCollectPeerProxyData, EEv::EvCollectPeerProxyData> {};
+
         struct TEvOnRequestTimeout: public TEventLocal<TEvOnRequestTimeout, EEv::EvOnRequestTimeout> {
             public:
                 ui64 RequestId;
@@ -135,8 +135,6 @@ class TKqpProxyService : public TActorBootstrapped<TKqpProxyService> {
 
             TEvOnRequestTimeout(ui64 requestId, TDuration timeout):  RequestId(requestId), Timeout(timeout) {};
         };
-
-        struct TEvCloseIdleSessions : public TEventLocal<TEvCloseIdleSessions, EEv::EvCloseIdleSessions> {};
     };
 
 public:
@@ -218,38 +216,6 @@ public:
         PublishResourceUsage();
         AskSelfNodeInfo();
         SendWhiteboardRequest();
-        ScheduleIdleSessionCheck();
-    }
-
-    void ScheduleIdleSessionCheck() {
-        if (!ShutdownState) {
-            const TDuration IdleSessionsCheckInterval = TDuration::Seconds(2);
-            Schedule(IdleSessionsCheckInterval, new TEvPrivate::TEvCloseIdleSessions());
-        }
-    }
-
-    void Handle(TEvPrivate::TEvCloseIdleSessions::TPtr&) {
-        CheckIdleSessions();
-        ScheduleIdleSessionCheck();
-    }
-
-    void CheckIdleSessions(const ui32 maxSessionsToClose = 10) {
-        ui32 closedIdleSessions = 0;
-        const NActors::TMonotonic now = TActivationContext::Monotonic();
-        while(true) {
-            const TKqpSessionInfo* sessionInfo = LocalSessions->GetIdleSession(now);
-            if (sessionInfo == nullptr || closedIdleSessions > maxSessionsToClose)
-                break;
-
-            SendSessionClose(sessionInfo);
-            ++closedIdleSessions;
-        }
-    }
-
-    void SendSessionClose(const TKqpSessionInfo* sessionInfo) {
-        auto closeSessionEv = std::make_unique<TEvKqp::TEvCloseSessionRequest>();
-        closeSessionEv->Record.MutableRequest()->SetSessionId(sessionInfo->SessionId);
-        Send(sessionInfo->WorkerId, closeSessionEv.release());
     }
 
     void AskSelfNodeInfo() {
@@ -376,7 +342,9 @@ public:
         KQP_PROXY_LOG_I("Received tenant pool status, serving tenants: " << JoinRange(", ", Tenants.begin(), Tenants.end()));
         for (auto& [_, sessionInfo] : *LocalSessions) {
             if (!sessionInfo.Database.empty() && !Tenants.contains(sessionInfo.Database)) {
-                SendSessionClose(&sessionInfo);
+                auto closeSessionEv = MakeHolder<TEvKqp::TEvCloseSessionRequest>();
+                closeSessionEv->Record.MutableRequest()->SetSessionId(sessionInfo.SessionId);
+                Send(sessionInfo.WorkerId, closeSessionEv.Release());
             }
         }
 
@@ -582,7 +550,6 @@ public:
         TActorId targetId;
         if (sessionInfo) {
             targetId = sessionInfo->WorkerId;
-            LocalSessions->StopIdleCheck(sessionInfo);
         } else {
             targetId = TryGetSessionTargetActor(request.GetSessionId(), requestInfo, requestId);
             if (!targetId) {
@@ -628,10 +595,6 @@ public:
         }
     }
 
-    TDuration GetSessionIdleDuration() const {
-        return TDuration::Seconds(TableServiceConfig.GetSessionIdleDurationSeconds());
-    }
-
     void Handle(TEvKqp::TEvPingSessionRequest::TPtr& ev) {
         auto& event = ev->Get()->Record;
         auto& request = event.GetRequest();
@@ -647,9 +610,7 @@ public:
         TActorId targetId;
         if (sessionInfo) {
             targetId = sessionInfo->WorkerId;
-            LocalSessions->StopIdleCheck(sessionInfo);
         } else {
-            // forward request to kqp proxy on the different node.
             targetId = TryGetSessionTargetActor(sessionId, requestInfo, requestId);
             if (!targetId) {
                 return;
@@ -677,11 +638,6 @@ public:
             return;
         }
 
-        const TKqpSessionInfo* info = LocalSessions->FindPtr(proxyRequest->SessionId);
-        if (info) {
-            LocalSessions->StartIdleCheck(info, GetSessionIdleDuration());
-        }
-
         LogResponse(proxyRequest->TraceId, ev->Get()->Record, proxyRequest->DbCounters);
         Send(proxyRequest->Sender, ev->Release().Release(), 0, proxyRequest->SenderCookie);
 
@@ -1041,7 +997,6 @@ public:
             hFunc(TEvPrivate::TEvOnRequestTimeout, Handle);
             hFunc(NNodeWhiteboard::TEvWhiteboard::TEvSystemStateResponse, Handle);
             hFunc(TEvKqp::TEvCreateSessionResponse, ForwardEvent);
-            hFunc(TEvPrivate::TEvCloseIdleSessions, Handle);
         default:
             Y_FAIL("TKqpProxyService: unexpected event type: %" PRIx32 " event: %s",
                 ev->GetTypeRewrite(), ev->HasEvent() ? ev->GetBase()->ToString().data() : "serialized?");
@@ -1202,7 +1157,7 @@ private:
                 ? CreateKqpSessionActor(SelfId(), sessionId, KqpSettings, workerSettings, ModuleResolverState, Counters)
                 : CreateKqpWorkerActor(SelfId(), sessionId, KqpSettings, workerSettings, ModuleResolverState, Counters);
         auto workerId = TlsActivationContext->ExecutorThread.RegisterActor(workerActor, TMailboxType::HTSwap, AppData()->UserPoolId);
-        TKqpSessionInfo* sessionInfo = LocalSessions->Create(sessionId, workerId, database, dbCounters, supportsBalancing, GetSessionIdleDuration());
+        TKqpSessionInfo* sessionInfo = LocalSessions->Create(sessionId, workerId, database, dbCounters, supportsBalancing);
 
         KQP_PROXY_LOG_D(requestInfo << "Created new session"
             << ", sessionId: " << sessionInfo->SessionId
diff --git a/ydb/core/kqp/proxy/kqp_proxy_service.h b/ydb/core/kqp/proxy/kqp_proxy_service.h
index d71b500559..e6d44a176c 100644
--- a/ydb/core/kqp/proxy/kqp_proxy_service.h
+++ b/ydb/core/kqp/proxy/kqp_proxy_service.h
@@ -78,26 +78,23 @@ struct TKqpSessionInfo {
     TActorId WorkerId;
     TString Database;
     TKqpDbCountersPtr DbCounters;
+    TInstant LastRequestAt;
+    TInstant CreatedAt;
     TInstant ShutdownStartedAt;
     std::vector<i32> ReadyPos;
-    NActors::TMonotonic IdleTimeout;
-    // position in the idle list.
-    std::list<TKqpSessionInfo*>::iterator IdlePos;
-
-    TKqpSessionInfo(
-        const TString& sessionId, const TActorId& workerId,
-        const TString& database, TKqpDbCountersPtr dbCounters, std::vector<i32>&& pos,
-        NActors::TMonotonic idleTimeout,
-        std::list<TKqpSessionInfo*>::iterator idlePos)
+
+    TKqpSessionInfo(const TString& sessionId, const TActorId& workerId,
+        const TString& database, TKqpDbCountersPtr dbCounters, std::vector<i32>&& pos)
         : SessionId(sessionId)
         , WorkerId(workerId)
         , Database(database)
         , DbCounters(dbCounters)
         , ShutdownStartedAt()
         , ReadyPos(std::move(pos))
-        , IdleTimeout(idleTimeout)
-        , IdlePos(idlePos)
     {
+        auto now = TAppData::TimeProvider->Now();
+        LastRequestAt = now;
+        CreatedAt = now;
     }
 };
 
@@ -116,6 +113,7 @@ struct TSimpleResourceStats {
 struct TPeerStats {
     TSimpleResourceStats LocalSessionCount;
     TSimpleResourceStats CrossAZSessionCount;
+
     TSimpleResourceStats LocalCpu;
     TSimpleResourceStats CrossAZCpu;
 
@@ -138,7 +136,6 @@ class TLocalSessionsRegistry {
     THashMap<TString, ui32> SessionsCountPerDatabase;
     std::vector<std::vector<TString>> ReadySessions;
     TIntrusivePtr<IRandomProvider> RandomProvider;
-    std::list<TKqpSessionInfo*> IdleSessions;
 
 public:
     TLocalSessionsRegistry(TIntrusivePtr<IRandomProvider> randomProvider)
@@ -147,8 +144,7 @@ public:
     {}
 
     TKqpSessionInfo* Create(const TString& sessionId, const TActorId& workerId,
-        const TString& database, TKqpDbCountersPtr dbCounters, bool supportsBalancing,
-        TDuration idleDuration)
+        const TString& database, TKqpDbCountersPtr dbCounters, bool supportsBalancing)
     {
         std::vector<i32> pos(2, -1);
         pos[0] = ReadySessions[0].size();
@@ -159,30 +155,13 @@ public:
             ReadySessions[1].push_back(sessionId);
         }
 
-        auto result = LocalSessions.emplace(
-            sessionId, TKqpSessionInfo(sessionId, workerId, database, dbCounters, std::move(pos),
-            NActors::TActivationContext::Monotonic() + idleDuration, IdleSessions.end()));
+        auto result = LocalSessions.emplace(sessionId, TKqpSessionInfo(sessionId, workerId, database, dbCounters, std::move(pos)));
         SessionsCountPerDatabase[database]++;
         Y_VERIFY(result.second, "Duplicate session id!");
         TargetIdIndex.emplace(workerId, sessionId);
-        StartIdleCheck(&(result.first->second), idleDuration);
         return &result.first->second;
     }
 
-    const TKqpSessionInfo* GetIdleSession(const NActors::TMonotonic& now) {
-        if (IdleSessions.empty()) {
-            return nullptr;
-        }
-
-        const TKqpSessionInfo* candidate = (*IdleSessions.begin());
-        if (candidate->IdleTimeout > now) {
-            return nullptr;
-        }
-
-        IdleSessions.erase(IdleSessions.begin());
-        return candidate;
-    }
-
     const THashSet<TString>& GetShutdownInFlight() const {
         return ShutdownInFlightSessions;
     }
@@ -217,31 +196,6 @@ public:
         return ShutdownInFlightSessions.size();
     }
 
-    void StartIdleCheck(const TKqpSessionInfo* sessionInfo, const TDuration idleDuration) {
-        if (!sessionInfo)
-            return;
-
-        TKqpSessionInfo* info = const_cast<TKqpSessionInfo*>(sessionInfo);
-
-        info->IdleTimeout = NActors::TActivationContext::Monotonic() + idleDuration;
-        if (info->IdlePos != IdleSessions.end()) {
-            IdleSessions.erase(info->IdlePos);
-        }
-
-        info->IdlePos = IdleSessions.insert(IdleSessions.end(), info);
-    }
-
-    void StopIdleCheck(const TKqpSessionInfo* sessionInfo) {
-        if (!sessionInfo)
-            return;
-
-        TKqpSessionInfo* info = const_cast<TKqpSessionInfo*>(sessionInfo);
-        if (info->IdlePos != IdleSessions.end()) {
-            IdleSessions.erase(info->IdlePos);
-            info->IdlePos = IdleSessions.end();
-        }
-    }
-
     void Erase(const TString& sessionId) {
         auto it = LocalSessions.find(sessionId);
         if (it != LocalSessions.end()) {
@@ -254,10 +208,6 @@ public:
             }
 
             RemoveSessionFromLists(&(it->second));
-            if (it->second.IdlePos != IdleSessions.end()) {
-                IdleSessions.erase(it->second.IdlePos);
-            }
-
             ShutdownInFlightSessions.erase(sessionId);
             TargetIdIndex.erase(it->second.WorkerId);
             LocalSessions.erase(it);
diff --git a/ydb/core/protos/config.proto b/ydb/core/protos/config.proto
index 719212cb6e..e03275ec3b 100644
--- a/ydb/core/protos/config.proto
+++ b/ydb/core/protos/config.proto
@@ -1172,7 +1172,6 @@ message TTableServiceConfig {
     optional uint32 CompileQueryCacheTTLSec = 20 [default = 0];
     optional TQueryReplayConfig QueryReplayConfig = 21;
     optional bool EnableKqpSessionActor = 23 [default = true];
-    optional uint32 SessionIdleDurationSeconds = 24 [default = 600];
 };
 
 // Config describes immediate controls and allows