bucket is property for external storage config->external storage

improve s3 tests usage
use special subscriber id for same mailbox problem resolving in tiering

30 files changed, 372 insertions, 325 deletions

diff --git a/ydb/core/base/events.h b/ydb/core/base/events.h
index e0d00c47671..1b3782b5d47 100644
--- a/ydb/core/base/events.h
+++ b/ydb/core/base/events.h
@@ -150,6 +150,8 @@ struct TKikimrEvents : TEvents {
         ES_DATASHARD_LOAD,
         ES_METADATA_PROVIDER,
         ES_INTERNAL_REQUEST,
+        ES_BACKGROUND_TASKS,
+        ES_TIERING
     };
 };
 
diff --git a/ydb/core/protos/services.proto b/ydb/core/protos/services.proto
index 4dd801466b4..c01581a8bb6 100644
--- a/ydb/core/protos/services.proto
+++ b/ydb/core/protos/services.proto
@@ -331,6 +331,12 @@ enum EServiceKikimr {
     // MetadataProvider
     METADATA_PROVIDER = 1500;
 
+    // Tiering
+    TX_TIERING = 1600;
+
+    // Background tasks
+    BG_TASKS = 1700;
+
 };
 
 message TActivity {
diff --git a/ydb/core/tx/columnshard/blob.cpp b/ydb/core/tx/columnshard/blob.cpp
index c7454238bfe..b0771a75f0f 100644
--- a/ydb/core/tx/columnshard/blob.cpp
+++ b/ydb/core/tx/columnshard/blob.cpp
@@ -132,23 +132,15 @@ TUnifiedBlobId ParseSmallBlobId(const TString& s, TString& error) {
     return TUnifiedBlobId(tabletId, gen, step, cookie, size);
 }
 
-// Format: "S3_key|bucket"
+// Format: "s = S3_key"
 TUnifiedBlobId ParseS3BlobId(const TString& s, TString& error) {
-    TVector<TString> keyBucket;
-    Split(s, "|", keyBucket);
-
-    if (keyBucket.size() != 2) {
-        error = TStringBuilder() << "Wrong S3 id '" << s << "'";
-        return TUnifiedBlobId();
-    }
-
     ui64 pathId;
-    TUnifiedBlobId dsBlobId = S3KeyToDsId(keyBucket[0], error, pathId);
+    TUnifiedBlobId dsBlobId = S3KeyToDsId(s, error, pathId);
     if (!dsBlobId.IsValid()) {
         return TUnifiedBlobId();
     }
 
-    return TUnifiedBlobId(dsBlobId, TUnifiedBlobId::S3_BLOB, keyBucket[1], pathId);
+    return TUnifiedBlobId(dsBlobId, TUnifiedBlobId::S3_BLOB, pathId);
 }
 
 }
diff --git a/ydb/core/tx/columnshard/blob.h b/ydb/core/tx/columnshard/blob.h
index 00228e7071c..c0f0e723531 100644
--- a/ydb/core/tx/columnshard/blob.h
+++ b/ydb/core/tx/columnshard/blob.h
@@ -87,13 +87,11 @@ class TUnifiedBlobId {
 
     struct TS3BlobId {
         TDsBlobId DsBlobId;
-        TString Bucket;
         TString Key;
 
         TS3BlobId() = default;
 
-        TS3BlobId(const TUnifiedBlobId& dsBlob, const TString& bucket, const ui64 pathId)
-            : Bucket(bucket)
+        TS3BlobId(const TUnifiedBlobId& dsBlob, const ui64 pathId)
         {
             Y_VERIFY(dsBlob.IsDsBlob());
             DsBlobId = std::get<TDsBlobId>(dsBlob.Id);
@@ -101,15 +99,15 @@ class TUnifiedBlobId {
         }
 
         bool operator == (const TS3BlobId& other) const {
-            return Bucket == other.Bucket && Key == other.Key;
+            return Key == other.Key;
         }
 
         TString ToStringNew() const {
-            return Sprintf("%s|%s", Key.c_str(), Bucket.c_str());
+            return Sprintf("%s", Key.c_str());
         }
 
         ui64 Hash() const {
-            return CombineHashes<ui64>(THash<TString>()(Bucket), THash<TString>()(Key));
+            return IntHash(THash<TString>()(Key));
         }
     };
 
@@ -143,8 +141,8 @@ public:
     {}
 
     // Make S3 blob Id from DS one
-    TUnifiedBlobId(const TUnifiedBlobId& blob, EBlobType type, const TString& bucket, const ui64 pathId)
-        : Id(TS3BlobId(blob, bucket, pathId))
+    TUnifiedBlobId(const TUnifiedBlobId& blob, EBlobType type, const ui64 pathId)
+        : Id(TS3BlobId(blob, pathId))
     {
         Y_VERIFY(type == S3_BLOB);
     }
diff --git a/ydb/core/tx/columnshard/columnshard_impl.cpp b/ydb/core/tx/columnshard/columnshard_impl.cpp
index 6b672049d45..0cbfb6079ee 100644
--- a/ydb/core/tx/columnshard/columnshard_impl.cpp
+++ b/ydb/core/tx/columnshard/columnshard_impl.cpp
@@ -5,6 +5,7 @@
 #include <ydb/core/tx/tiering/external_data.h>
 #include <ydb/core/tx/columnshard/engines/column_engine_logs.h>
 #include <ydb/services/metadata/service.h>
+#include <ydb/core/tx/tiering/manager.h>
 
 namespace NKikimr::NColumnShard {
 
@@ -951,7 +952,7 @@ NOlap::TIndexInfo TColumnShard::ConvertSchema(const NKikimrSchemeOp::TColumnTabl
 
     EnableTiering = schema.GetEnableTiering();
     if (OwnerPath && !Tiers && EnableTiering) {
-        Tiers = std::make_shared<TTiersManager>(TabletID(), OwnerPath);
+        Tiers = std::make_shared<TTiersManager>(TabletID(), SelfId(), OwnerPath);
     }
     if (!!Tiers) {
         if (EnableTiering) {
@@ -1044,7 +1045,7 @@ TActorId TColumnShard::GetS3ActorForTier(const TString& tierName) const {
 
 void TColumnShard::Handle(NMetadataProvider::TEvRefreshSubscriberData::TPtr& ev) {
     if (!Tiers) {
-        Tiers = std::make_shared<TTiersManager>(TabletID(), OwnerPath);
+        Tiers = std::make_shared<TTiersManager>(TabletID(), SelfId(), OwnerPath);
     }
     Tiers->TakeConfigs(ev->Get()->GetSnapshot());
     if (EnableTiering) {
diff --git a/ydb/core/tx/columnshard/ut_columnshard_schema.cpp b/ydb/core/tx/columnshard/ut_columnshard_schema.cpp
index 9cf3766c597..7dd77b12ed2 100644
--- a/ydb/core/tx/columnshard/ut_columnshard_schema.cpp
+++ b/ydb/core/tx/columnshard/ut_columnshard_schema.cpp
@@ -595,7 +595,7 @@ void TestTwoHotTiers(bool reboot) {
 }
 
 void TestHotAndColdTiers(bool reboot) {
-    TString bucket = "ydb";
+    const TString bucket = "tiering-test-01";
     TPortManager portManager;
     const ui16 port = portManager.GetPort();
 
@@ -612,9 +612,10 @@ void TestHotAndColdTiers(bool reboot) {
 
         s3Config.SetScheme(NKikimrSchemeOp::TS3Settings::HTTP);
         s3Config.SetVerifySSL(false);
-#if 0
+        s3Config.SetBucket(bucket);
+//#define S3_TEST_USAGE
+#ifdef S3_TEST_USAGE
         s3Config.SetEndpoint("storage.cloud-preprod.yandex.net");
-        s3Config.SetBucket("tiering-test-01");
         s3Config.SetAccessKey("...");
         s3Config.SetSecretKey("...");
         s3Config.SetProxyHost("localhost");
@@ -622,7 +623,6 @@ void TestHotAndColdTiers(bool reboot) {
         s3Config.SetProxyScheme(NKikimrSchemeOp::TS3Settings::HTTP);
 #else
         s3Config.SetEndpoint("fake");
-        s3Config.SetBucket(bucket);
 #endif
         s3Config.SetRequestTimeoutMs(10000);
         s3Config.SetHttpRequestTimeoutMs(10000);
diff --git a/ydb/core/tx/datashard/export_s3_base_uploader.h b/ydb/core/tx/datashard/export_s3_base_uploader.h
index 1acce848bc4..8ebc1a79ffc 100644
--- a/ydb/core/tx/datashard/export_s3_base_uploader.h
+++ b/ydb/core/tx/datashard/export_s3_base_uploader.h
@@ -79,7 +79,6 @@ protected:
         google::protobuf::TextFormat::PrintToString(Scheme.GetRef(), &Buffer);
 
         auto request = Aws::S3::Model::PutObjectRequest()
-            .WithBucket(Settings.GetBucket())
             .WithKey(Settings.GetSchemeKey())
             .WithStorageClass(Settings.GetStorageClass());
         this->Send(Client, new TEvExternalStorage::TEvPutObjectRequest(request, std::move(Buffer)));
@@ -145,7 +144,6 @@ protected:
     void UploadData() {
         if (!MultiPart) {
             auto request = Aws::S3::Model::PutObjectRequest()
-                .WithBucket(Settings.GetBucket())
                 .WithKey(Settings.GetDataKey(DataFormat, CompressionCodec))
                 .WithStorageClass(Settings.GetStorageClass());
             this->Send(Client, new TEvExternalStorage::TEvPutObjectRequest(request, std::move(Buffer)));
@@ -156,7 +154,6 @@ protected:
             }
 
             auto request = Aws::S3::Model::UploadPartRequest()
-                .WithBucket(Settings.GetBucket())
                 .WithKey(Settings.GetDataKey(DataFormat, CompressionCodec))
                 .WithUploadId(*UploadId)
                 .WithPartNumber(Parts.size() + 1);
@@ -187,7 +184,6 @@ protected:
 
         if (!upload) {
             auto request = Aws::S3::Model::CreateMultipartUploadRequest()
-                .WithBucket(Settings.GetBucket())
                 .WithKey(Settings.GetDataKey(DataFormat, CompressionCodec))
                 .WithStorageClass(Settings.GetStorageClass());
             this->Send(Client, new TEvExternalStorage::TEvCreateMultipartUploadRequest(request));
@@ -209,7 +205,6 @@ protected:
                     }
 
                     auto request = Aws::S3::Model::CompleteMultipartUploadRequest()
-                        .WithBucket(Settings.GetBucket())
                         .WithKey(Settings.GetDataKey(DataFormat, CompressionCodec))
                         .WithUploadId(*UploadId)
                         .WithMultipartUpload(Aws::S3::Model::CompletedMultipartUpload().WithParts(std::move(parts)));
@@ -224,7 +219,6 @@ protected:
                     }
 
                     auto request = Aws::S3::Model::AbortMultipartUploadRequest()
-                        .WithBucket(Settings.GetBucket())
                         .WithKey(Settings.GetDataKey(DataFormat, CompressionCodec))
                         .WithUploadId(*UploadId);
                     this->Send(Client, new TEvExternalStorage::TEvAbortMultipartUploadRequest(request));
diff --git a/ydb/core/tx/datashard/import_s3.cpp b/ydb/core/tx/datashard/import_s3.cpp
index ba4f23c09d0..cb91713f93a 100644
--- a/ydb/core/tx/datashard/import_s3.cpp
+++ b/ydb/core/tx/datashard/import_s3.cpp
@@ -357,7 +357,6 @@ class TS3Downloader: public TActorBootstrapped<TS3Downloader> {
             << ": key# " << key);
 
         auto request = Model::HeadObjectRequest()
-            .WithBucket(Settings.GetBucket())
             .WithKey(key);
 
         Send(Client, new TEvExternalStorage::TEvHeadObjectRequest(request));
@@ -369,7 +368,6 @@ class TS3Downloader: public TActorBootstrapped<TS3Downloader> {
             << ", range# " << range.first << "-" << range.second);
 
         auto request = Model::GetObjectRequest()
-            .WithBucket(Settings.GetBucket())
             .WithKey(key)
             .WithRange(TStringBuilder() << "bytes=" << range.first << "-" << range.second);
 
diff --git a/ydb/core/tx/schemeshard/schemeshard_import_scheme_getter.cpp b/ydb/core/tx/schemeshard/schemeshard_import_scheme_getter.cpp
index a95794cdcf9..5819f9f5567 100644
--- a/ydb/core/tx/schemeshard/schemeshard_import_scheme_getter.cpp
+++ b/ydb/core/tx/schemeshard/schemeshard_import_scheme_getter.cpp
@@ -29,7 +29,6 @@ class TSchemeGetter: public TActorBootstrapped<TSchemeGetter> {
 
     void HeadObject(const TString& key) {
         auto request = Model::HeadObjectRequest()
-            .WithBucket(ImportInfo->Settings.bucket())
             .WithKey(key);
 
         Send(Client, new TEvExternalStorage::TEvHeadObjectRequest(request));
@@ -52,7 +51,6 @@ class TSchemeGetter: public TActorBootstrapped<TSchemeGetter> {
 
     void GetObject(const TString& key, const std::pair<ui64, ui64>& range) {
         auto request = Model::GetObjectRequest()
-            .WithBucket(ImportInfo->Settings.bucket())
             .WithKey(key)
             .WithRange(TStringBuilder() << "bytes=" << range.first << "-" << range.second);
 
@@ -137,7 +135,6 @@ public:
         if (Client) {
             Send(Client, new TEvents::TEvPoisonPill());
         }
-
         Client = RegisterWithSameMailbox(CreateS3Wrapper(ExternalStorageConfig->ConstructStorageOperator()));
 
         HeadObject(SchemeKey);
diff --git a/ydb/core/tx/tiering/manager.cpp b/ydb/core/tx/tiering/manager.cpp
index 114b634406a..a9cd24a2c75 100644
--- a/ydb/core/tx/tiering/manager.cpp
+++ b/ydb/core/tx/tiering/manager.cpp
@@ -30,7 +30,7 @@ public:
     }
     void Bootstrap() {
         Become(&TThis::StateMain);
-        Send(GetExternalDataActorId(), new NMetadataProvider::TEvSubscribeExternal(Owner->GetExternalDataManipulation()));
+        Send(GetExternalDataActorId(), new NMetadataProvider::TEvSubscribeExternal(Owner->GetExternalDataManipulation(), SelfId()));
     }
     void Handle(NMetadataProvider::TEvRefreshSubscriberData::TPtr& ev) {
         auto snapshot = ev->Get()->GetSnapshot();
@@ -79,7 +79,7 @@ bool TManager::Start() {
 #ifndef KIKIMR_DISABLE_S3_OPS
     auto& ctx = TActivationContext::AsActorContext();
     const NActors::TActorId newActor = ctx.Register(
-        CreateS3Actor(TabletId, ctx.SelfID, Config.GetTierName())
+        CreateS3Actor(TabletId, TabletActorId, Config.GetTierName())
     );
     ctx.Send(newActor, new TEvPrivate::TEvS3Settings(Config.GetProtoConfig().GetObjectStorage()));
     Stop();
@@ -88,9 +88,11 @@ bool TManager::Start() {
     return true;
 }
 
-TManager::TManager(const ui64 tabletId, const TTierConfig& config)
+TManager::TManager(const ui64 tabletId, const NActors::TActorId& tabletActorId, const TTierConfig& config)
     : TabletId(tabletId)
-    , Config(config) {
+    , TabletActorId(tabletActorId)
+    , Config(config)
+{
 }
 
 NOlap::TStorageTier TManager::BuildTierStorage() const {
@@ -147,7 +149,7 @@ void TTiersManager::TakeConfigs(NMetadataProvider::ISnapshot::TPtr snapshotExt)
         if (Managers.contains(i.second.GetTierName())) {
             continue;
         }
-        NTiers::TManager localManager(TabletId, i.second);
+        NTiers::TManager localManager(TabletId, TabletActorId, i.second);
         auto& manager = Managers.emplace(i.second.GetTierName(), std::move(localManager)).first->second;
         if (IsActive()) {
             manager.Start();
@@ -158,12 +160,12 @@ void TTiersManager::TakeConfigs(NMetadataProvider::ISnapshot::TPtr snapshotExt)
 TActorId TTiersManager::GetStorageActorId(const TString& tierName) {
     auto it = Managers.find(tierName);
     if (it == Managers.end()) {
-        ALS_ERROR(NKikimrServices::TX_COLUMNSHARD) << "No S3 actor for tier '" << tierName << "' at tablet " << TabletId;
+        ALS_ERROR(NKikimrServices::TX_TIERING) << "No S3 actor for tier '" << tierName << "' at tablet " << TabletId;
         return {};
     }
     auto actorId = it->second.GetStorageActorId();
     if (!actorId) {
-        ALS_ERROR(NKikimrServices::TX_COLUMNSHARD) << "Not started storage actor for tier '" << tierName << "' at tablet " << TabletId;
+        ALS_ERROR(NKikimrServices::TX_TIERING) << "Not started storage actor for tier '" << tierName << "' at tablet " << TabletId;
         return {};
     }
     return actorId;
@@ -234,4 +236,12 @@ TTiersManager::~TTiersManager() {
     }
 }
 
+TActorId TTiersManager::GetActorId() const {
+    if (Actor) {
+        return Actor->SelfId();
+    } else {
+        return {};
+    }
+}
+
 }
diff --git a/ydb/core/tx/tiering/manager.h b/ydb/core/tx/tiering/manager.h
index 4313aefce42..008682a8917 100644
--- a/ydb/core/tx/tiering/manager.h
+++ b/ydb/core/tx/tiering/manager.h
@@ -13,10 +13,11 @@ namespace NTiers {
 class TManager {
 private:
     ui64 TabletId = 0;
+    YDB_READONLY_DEF(NActors::TActorId, TabletActorId);
     YDB_READONLY_DEF(TTierConfig, Config);
     YDB_READONLY_DEF(NActors::TActorId, StorageActorId);
 public:
-    TManager(const ui64 tabletId, const TTierConfig& config);
+    TManager(const ui64 tabletId, const NActors::TActorId& tabletActorId, const TTierConfig& config);
     static NOlap::TCompression ConvertCompression(const NKikimrSchemeOp::TCompressionOptions& compression);
     NOlap::TStorageTier BuildTierStorage() const;
 
@@ -34,6 +35,7 @@ private:
     class TActor;
     using TManagers = TMap<TString, NTiers::TManager>;
     ui64 TabletId = 0;
+    const TActorId TabletActorId;
     TString OwnerPath;
     TActor* Actor = nullptr;
     YDB_READONLY_DEF(TManagers, Managers);
@@ -43,11 +45,13 @@ private:
     mutable NMetadataProvider::ISnapshotParser::TPtr ExternalDataManipulation;
 
 public:
-    TTiersManager(const ui64 tabletId, const TString& ownerPath)
+    TTiersManager(const ui64 tabletId, const TActorId& tabletActorId, const TString& ownerPath)
         : TabletId(tabletId)
+        , TabletActorId(tabletActorId)
         , OwnerPath(ownerPath)
     {
     }
+    TActorId GetActorId() const;
     ~TTiersManager();
     THashMap<ui64, NOlap::TTiersInfo> GetTiering() const;
     void TakeConfigs(NMetadataProvider::ISnapshot::TPtr snapshot);
diff --git a/ydb/core/tx/tiering/s3_actor.cpp b/ydb/core/tx/tiering/s3_actor.cpp
index d9136104748..5dd253607e3 100644
--- a/ydb/core/tx/tiering/s3_actor.cpp
+++ b/ydb/core/tx/tiering/s3_actor.cpp
@@ -32,8 +32,8 @@ public:
         return Event->Blobs;
     }
 
-    TUnifiedBlobId AddExported(const TString& bucket, const TUnifiedBlobId& srcBlob, const ui64 pathId) {
-        Event->SrcToDstBlobs[srcBlob] = TUnifiedBlobId(srcBlob, TUnifiedBlobId::S3_BLOB, bucket, pathId);
+    TUnifiedBlobId AddExported(const TUnifiedBlobId& srcBlob, const ui64 pathId) {
+        Event->SrcToDstBlobs[srcBlob] = TUnifiedBlobId(srcBlob, TUnifiedBlobId::S3_BLOB, pathId);
         return Event->SrcToDstBlobs[srcBlob];
     }
 
@@ -74,9 +74,9 @@ public:
         return NKikimrServices::TActivity::TX_COLUMNSHARD_S3_ACTOR;
     }
 
-    TS3Actor(ui64 tabletId, const TActorId& parent, const TString& tierName)
+    TS3Actor(ui64 tabletId, const TActorId& shardActor, const TString& tierName)
         : TabletId(tabletId)
-        , ShardActor(parent)
+        , ShardActor(shardActor)
         , TierName(tierName)
     {}
 
@@ -88,16 +88,16 @@ public:
     void Handle(TEvPrivate::TEvS3Settings::TPtr& ev) {
         auto& msg = *ev->Get();
         auto& endpoint = msg.Settings.GetEndpoint();
-        Bucket = msg.Settings.GetBucket();
+        const auto& bucket = msg.Settings.GetBucket();
 
         LOG_S_DEBUG("[S3] Update settings for tier '" << TierName << "' endpoint '" << endpoint
-            << "' bucket '" << Bucket << "' at tablet " << TabletId);
+            << "' bucket '" << bucket << "' at tablet " << TabletId);
 
         if (endpoint.empty()) {
             LOG_S_ERROR("[S3] No endpoint in settings for tier '" << TierName << "' at tablet " << TabletId);
             return;
         }
-        if (Bucket.empty()) {
+        if (bucket.empty()) {
             LOG_S_ERROR("[S3] No bucket in settings for tier '" << TierName << "' at tablet " << TabletId);
             return;
         }
@@ -113,13 +113,14 @@ public:
     void Handle(TEvPrivate::TEvExport::TPtr& ev) {
         auto& msg = *ev->Get();
         ui64 exportNo = msg.ExportNo;
+        Y_VERIFY(ev->Get()->DstActor == ShardActor);
 
         Y_VERIFY(!Exports.count(exportNo));
         Exports[exportNo] = TS3Export(ev->Release());
         auto& ex = Exports[exportNo];
 
         for (auto& [blobId, blob] : ex.Blobs()) {
-            TString key = ex.AddExported(Bucket, blobId, blob.PathId).GetS3Key();
+            TString key = ex.AddExported(blobId, blob.PathId).GetS3Key();
             Y_VERIFY(!ExportingKeys.count(key)); // TODO
 
             ex.RegisterKey(key);
@@ -221,7 +222,11 @@ public:
         if (!context) {
             return;
         }
-        if (!msg.IsExists()) {
+        const auto& resultOutcome = msg.Result;
+
+        if (!resultOutcome.IsSuccess()) {
+            KeyFinished(context->GetKey(), true, LogError("CheckObjectExistsResponse", resultOutcome.GetError(), !!context->GetKey()));
+        } else if (!msg.IsExists()) {
             SendPutObject(context->GetKey(), std::move(context->DetachData()));
         } else {
             KeyFinished(context->GetKey(), false, "");
@@ -348,7 +353,6 @@ public:
 
         auto& ex = it->second;
         ex.FinishKey(key);
-        Y_VERIFY(ex.Event->DstActor == ShardActor);
 
         if (hasError) {
             ex.Event->Status = NKikimrProto::ERROR;
@@ -370,7 +374,6 @@ private:
     ui64 TabletId;
     TActorId ShardActor;
     TString TierName;
-    TString Bucket;
     ui64 ForgetNo{};
     THashMap<ui64, TS3Export> Exports;
     THashMap<ui64, TS3Forget> Forgets;
@@ -412,7 +415,6 @@ private:
 
     void SendPutObject(const TString& key, TString&& data) const {
         auto request = Aws::S3::Model::PutObjectRequest()
-            .WithBucket(Bucket)
             .WithKey(key)
             .WithStorageClass(Aws::S3::Model::StorageClass::STANDARD_IA);
 #if 0
@@ -425,18 +427,16 @@ private:
     }
 
     void SendPutObjectIfNotExists(const TString& key, TString&& data) {
-        auto request = Aws::S3::Model::HeadObjectRequest()
-            .WithBucket(Bucket)
-            .WithKey(key);
+        auto request = Aws::S3::Model::ListObjectsRequest()
+            .WithPrefix(key);
 
-        LOG_S_DEBUG("[S3] HeadObjectRequest key '" << key << "' at tablet " << TabletId);
+        LOG_S_DEBUG("[S3] PutObjectIfNotExists->ListObjectsRequest key '" << key << "' at tablet " << TabletId);
         std::shared_ptr<TEvCheckObjectExistsRequestContext> context = std::make_shared<TEvCheckObjectExistsRequestContext>(key, std::move(data));
         Send(ExternalStorageActorId, new TEvExternalStorage::TEvCheckObjectExistsRequest(request, context));
     }
 
     void SendHeadObject(const TString& key) const {
         auto request = Aws::S3::Model::HeadObjectRequest()
-            .WithBucket(Bucket)
             .WithKey(key);
 
         LOG_S_DEBUG("[S3] HeadObjectRequest key '" << key << "' at tablet " << TabletId);
@@ -446,7 +446,6 @@ private:
     void SendGetObject(const TString& key, const ui32 startPos, const ui32 size) {
         Y_VERIFY(size);
         auto request = Aws::S3::Model::GetObjectRequest()
-            .WithBucket(Bucket)
             .WithKey(key)
             .WithRange(TStringBuilder() << "bytes=" << startPos << "-" << startPos + size - 1);
 
@@ -456,7 +455,6 @@ private:
 
     void SendDeleteObject(const TString& key) const {
         auto request = Aws::S3::Model::DeleteObjectRequest()
-            .WithBucket(Bucket)
             .WithKey(key);
 
         Send(ExternalStorageActorId, new TEvExternalStorage::TEvDeleteObjectRequest(request));
diff --git a/ydb/core/wrappers/abstract.cpp b/ydb/core/wrappers/abstract.cpp
index be0fde71922..13c4f1bdddc 100644
--- a/ydb/core/wrappers/abstract.cpp
+++ b/ydb/core/wrappers/abstract.cpp
@@ -12,7 +12,7 @@ IExternalStorageOperator::TPtr IExternalStorageConfig::ConstructStorageOperator(
 
 IExternalStorageConfig::TPtr IExternalStorageConfig::Construct(const NKikimrSchemeOp::TS3Settings& settings) {
     if (settings.GetEndpoint() == "fake") {
-        return std::make_shared<TFakeExternalStorageConfig>();
+        return std::make_shared<TFakeExternalStorageConfig>(settings.GetBucket());
     } else {
         return std::make_shared <TS3ExternalStorageConfig>(settings);
     }
diff --git a/ydb/core/wrappers/events/common.h b/ydb/core/wrappers/events/common.h
index e051437533c..632e63b2386 100644
--- a/ydb/core/wrappers/events/common.h
+++ b/ydb/core/wrappers/events/common.h
@@ -13,20 +13,33 @@ namespace NKikimr::NWrappers::NExternalStorage {
 
 template <typename TDerived, ui32 EventType, typename T>
 struct TGenericRequest: public NActors::TEventLocal<TDerived, EventType> {
+private:
+    IRequestContext::TPtr RequestContext;
+public:
     using TRequest = T;
     TRequest Request;
     IRequestContext::TPtr GetRequestContext() const {
-        return nullptr;
+        return RequestContext;
     }
 
     const TRequest& GetRequest() const {
         return Request;
     }
 
+    TRequest& MutableRequest() {
+        return Request;
+    }
+
     explicit TGenericRequest(const TRequest& request)
         : Request(request) {
     }
 
+    TGenericRequest(const TRequest& request, IRequestContext::TPtr requestContext)
+        : RequestContext(requestContext)
+        , Request(request)
+    {
+    }
+
     TString ToString() const override {
         return TStringBuilder() << this->ToStringHeader() << " {"
             << " Request: " << Request
@@ -57,47 +70,100 @@ struct TRequestWithBody: public TGenericRequest<TDerived, EventType, T> {
     using TBase = TRequestWithBody<TDerived, EventType, T>;
 };
 
-template <typename TDerived, ui32 EventType, typename T, typename U = T>
-struct TGenericResponse: public NActors::TEventLocal<TDerived, EventType> {
-    using TOutcome = Aws::Utils::Outcome<T, Aws::S3::S3Error>;
+template <typename TDerived, ui32 EventType, typename TAWSResultExt, typename U = TAWSResultExt>
+struct TBaseGenericResponse: public NActors::TEventLocal<TDerived, EventType> {
+private:
+    using TBase = NActors::TEventLocal<TDerived, EventType>;
+    IRequestContext::TPtr RequestContext;
+public:
+    using TOutcome = Aws::Utils::Outcome<TAWSResultExt, Aws::S3::S3Error>;
     using TResult = Aws::Utils::Outcome<U, Aws::S3::S3Error>;
+    using TAWSResult = U;
+    using TAWSOutcome = TResult;
     using TKey = std::optional<TString>;
 
-    TKey Key;
     TResult Result;
 
-    explicit TGenericResponse(const TKey& key, const TOutcome& outcome)
-        : Key(key)
+    explicit TBaseGenericResponse(const TOutcome& outcome)
+        : Result(TDerived::ResultFromOutcome(outcome)) {
+    }
+
+    TBaseGenericResponse(const TOutcome& outcome, IRequestContext::TPtr requestContext)
+        : RequestContext(requestContext)
         , Result(TDerived::ResultFromOutcome(outcome)) {
     }
 
+    bool IsSuccess() const {
+        return Result.IsSuccess();
+    }
+    const Aws::S3::S3Error& GetError() const {
+        return Result.GetError();
+    }
+    const U& GetResult() const {
+        return Result.GetResult();
+    }
+
+    template <class T>
+    std::shared_ptr<T> GetRequestContextAs() const {
+        return dynamic_pointer_cast<T>(RequestContext);
+    }
+
     static TResult ResultFromOutcome(const TOutcome& outcome) {
         return outcome;
     }
 
     TString ToString() const override {
         return TStringBuilder() << this->ToStringHeader() << " {"
-            << " Key: " << (Key ? "null" : *Key)
             << " Result: " << Result
             << " }";
     }
+};
 
-    using TBase = TGenericResponse<TDerived, EventType, T, U>;
+template <typename TDerived, ui32 EventType, typename TAWSResult, typename U = TAWSResult>
+struct TGenericResponse: public TBaseGenericResponse<TDerived, EventType, TAWSResult, U> {
+private:
+    using TBase = TBaseGenericResponse<TDerived, EventType, TAWSResult, U>;
+public:
+    using TOutcome = typename TBase::TOutcome;
+    using TResult = typename TBase::TResult;
+    using TKey = std::optional<TString>;
+
+    TKey Key;
+
+    TGenericResponse(const TKey& key, const TOutcome& outcome)
+        : TBase(outcome)
+        , Key(key) {
+    }
+
+    TGenericResponse(const TKey& key, const TOutcome& outcome, IRequestContext::TPtr requestContext)
+        : TBase(outcome, requestContext)
+        , Key(key)
+    {
+    }
+
+    TString ToString() const override {
+        return TStringBuilder() << this->ToStringHeader() << " {"
+            << " Key: " << (Key ? "null" : *Key)
+            << " Result: " << TBase::Result
+            << " }";
+    }
 };
 
 template <typename TDerived, ui32 EventType, typename T, typename U>
 struct TResponseWithBody: public TGenericResponse<TDerived, EventType, T, U> {
-    using TGeneric = TGenericResponse<TDerived, EventType, T, U>;
-    using TKey = typename TGeneric::TKey;
+private:
+    using TBase = TGenericResponse<TDerived, EventType, T, U>;
+public:
+    using TKey = typename TBase::TKey;
 
     TString Body;
 
-    explicit TResponseWithBody(const TKey& key, const typename TGeneric::TOutcome& outcome)
-        : TGeneric(key, outcome) {
+    explicit TResponseWithBody(const TKey& key, const typename TBase::TOutcome& outcome)
+        : TBase(key, outcome) {
     }
 
-    explicit TResponseWithBody(const TKey& key, const typename TGeneric::TOutcome& outcome, TString&& body)
-        : TGeneric(key, outcome)
+    explicit TResponseWithBody(const TKey& key, const typename TBase::TOutcome& outcome, TString&& body)
+        : TBase(key, outcome)
         , Body(std::move(body)) {
     }
 
@@ -108,8 +174,6 @@ struct TResponseWithBody: public TGenericResponse<TDerived, EventType, T, U> {
             << " Body: " << Body.size() << "b"
             << " }";
     }
-
-    using TBase = TResponseWithBody<TDerived, EventType, T, U>;
 };
 
 #define DEFINE_REQUEST(name, base) \
@@ -121,14 +185,21 @@ struct TResponseWithBody: public TGenericResponse<TDerived, EventType, T, U> {
         DEFINE_REQUEST(name, TGenericRequest)
 
 #define DECLARE_GENERIC_RESPONSE(name) \
-        struct TEv##name##Response: public TGenericResponse<TEv##name##Response, Ev##name##Response, Aws::S3::Model::name##Result>
+        struct TEv##name##Response: public TGenericResponse<TEv##name##Response, Ev##name##Response, Aws::S3::Model::name##Result> {\
+        private:\
+            using TBase = TGenericResponse<TEv##name##Response, Ev##name##Response, Aws::S3::Model::name##Result>;\
+        public:\
+            using TBase::TBase;
 
 #define DECLARE_RESPONSE_WITH_BODY(name, result_t) \
-        struct TEv##name##Response: public TResponseWithBody<TEv##name##Response, Ev##name##Response, Aws::S3::Model::name##Result, result_t>
+        struct TEv##name##Response: public TResponseWithBody<TEv##name##Response, Ev##name##Response, Aws::S3::Model::name##Result, result_t> {\
+        private:\
+            using TBase = TResponseWithBody<TEv##name##Response, Ev##name##Response, Aws::S3::Model::name##Result, result_t>;\
+        public:\
+            using TBase::TBase;
 
 #define DEFINE_GENERIC_RESPONSE(name) \
-        DECLARE_GENERIC_RESPONSE(name) { \
-            using TBase::TBase; \
+        DECLARE_GENERIC_RESPONSE(name) \
         }
 
 #define DEFINE_GENERIC_REQUEST_RESPONSE(name) \
@@ -136,7 +207,7 @@ struct TResponseWithBody: public TGenericResponse<TDerived, EventType, T, U> {
         DEFINE_GENERIC_RESPONSE(name)
 
 DEFINE_GENERIC_REQUEST(GetObject);
-DECLARE_RESPONSE_WITH_BODY(GetObject, Aws::String) {
+DECLARE_RESPONSE_WITH_BODY(GetObject, Aws::String)
     static TResult ResultFromOutcome(const TOutcome & outcome) {
         if (outcome.IsSuccess()) {
             return outcome.GetResult().GetETag();
@@ -144,8 +215,6 @@ DECLARE_RESPONSE_WITH_BODY(GetObject, Aws::String) {
             return outcome.GetError();
         }
     }
-
-    using TBase::TBase;
 };
 
 DEFINE_REQUEST(PutObject, TRequestWithBody);
diff --git a/ydb/core/wrappers/events/delete_objects.h b/ydb/core/wrappers/events/delete_objects.h
index f4da8e49bbd..f8c6945fb69 100644
--- a/ydb/core/wrappers/events/delete_objects.h
+++ b/ydb/core/wrappers/events/delete_objects.h
@@ -13,51 +13,18 @@
 
 namespace NKikimr::NWrappers::NExternalStorage {
 
-    class TEvDeleteObjectsRequest: public TEventLocal<TEvDeleteObjectsRequest, EvDeleteObjectsRequest> {
-    public:
-        using TRequest = Aws::S3::Model::DeleteObjectsRequest;
+    class TEvDeleteObjectsRequest: public TGenericRequest<TEvDeleteObjectsRequest, EvDeleteObjectsRequest, Aws::S3::Model::DeleteObjectsRequest> {
     private:
-        TRequest Request;
+        using TBase = TGenericRequest<TEvDeleteObjectsRequest, EvDeleteObjectsRequest, Aws::S3::Model::DeleteObjectsRequest>;
     public:
-        TEvDeleteObjectsRequest(const TRequest& request)
-            : Request(request) {
-
-        }
-        IRequestContext::TPtr GetRequestContext() const {
-            return nullptr;
-        }
-        const TRequest& GetRequest() const {
-            return Request;
-        }
-        TRequest* operator->() {
-            return &Request;
-        }
+        using TBase::TBase;
     };
-    class TEvDeleteObjectsResponse: public TEventLocal<TEvDeleteObjectsResponse, EvDeleteObjectsResponse> {
-    public:
-        using TResult = Aws::S3::Model::DeleteObjectsResult;
-        using TOutcome = Aws::Utils::Outcome<TResult, Aws::S3::S3Error>;
-        using TKey = std::optional<TString>;
+
+    class TEvDeleteObjectsResponse: public TBaseGenericResponse<TEvDeleteObjectsResponse, EvDeleteObjectsResponse, Aws::S3::Model::DeleteObjectsResult> {
     private:
-        TOutcome Outcome;
+        using TBase = TBaseGenericResponse<TEvDeleteObjectsResponse, EvDeleteObjectsResponse, Aws::S3::Model::DeleteObjectsResult>;
     public:
-        TEvDeleteObjectsResponse(const TOutcome& result)
-            : Outcome(result)
-        {
-
-        }
-        bool IsSuccess() const {
-            return Outcome.IsSuccess();
-        }
-        const Aws::S3::S3Error& GetError() const {
-            return Outcome.GetError();
-        }
-        const TResult& GetResult() const {
-            return Outcome.GetResult();
-        }
-        const TResult* operator->() const {
-            return &Outcome.GetResult();
-        }
+        using TBase::TBase;
     };
 
 }
diff --git a/ydb/core/wrappers/events/list_objects.h b/ydb/core/wrappers/events/list_objects.h
index 714296c5574..b2fa83aedee 100644
--- a/ydb/core/wrappers/events/list_objects.h
+++ b/ydb/core/wrappers/events/list_objects.h
@@ -13,48 +13,18 @@
 
 namespace NKikimr::NWrappers::NExternalStorage {
 
-    class TEvListObjectsRequest: public TEventLocal<TEvListObjectsRequest, EvListObjectsRequest> {
-    public:
-        using TRequest = Aws::S3::Model::ListObjectsRequest;
+    class TEvListObjectsRequest: public TGenericRequest<TEvListObjectsRequest, EvListObjectsRequest, Aws::S3::Model::ListObjectsRequest> {
     private:
-        TRequest Request;
+        using TBase = TGenericRequest<TEvListObjectsRequest, EvListObjectsRequest, Aws::S3::Model::ListObjectsRequest>;
     public:
-        TEvListObjectsRequest(const TRequest& request)
-            : Request(request) {
-
-        }
-        IRequestContext::TPtr GetRequestContext() const {
-            return nullptr;
-        }
-        const TRequest& GetRequest() const {
-            return Request;
-        }
-        TRequest* operator->() {
-            return &Request;
-        }
+        using TBase::TBase;
     };
-    class TEvListObjectsResponse: public TEventLocal<TEvListObjectsResponse, EvListObjectsResponse> {
-    public:
-        using TResult = Aws::S3::Model::ListObjectsResult;
-        using TOutcome = Aws::Utils::Outcome<TResult, Aws::S3::S3Error>;
-        using TKey = std::optional<TString>;
+
+    class TEvListObjectsResponse: public TBaseGenericResponse<TEvListObjectsResponse, EvListObjectsResponse, Aws::S3::Model::ListObjectsResult> {
     private:
-        TOutcome Outcome;
+        using TBase = TBaseGenericResponse<TEvListObjectsResponse, EvListObjectsResponse, Aws::S3::Model::ListObjectsResult>;
     public:
-        TEvListObjectsResponse(const TOutcome& result)
-            : Outcome(result)
-        {
-
-        }
-        bool IsSuccess() const {
-            return Outcome.IsSuccess();
-        }
-        const TResult& GetResult() const {
-            return Outcome.GetResult();
-        }
-        const TResult* operator->() const {
-            return &Outcome.GetResult();
-        }
+        using TBase::TBase;
     };
 
 }
diff --git a/ydb/core/wrappers/events/object_exists.h b/ydb/core/wrappers/events/object_exists.h
index 2c6128e507a..d16a06143ef 100644
--- a/ydb/core/wrappers/events/object_exists.h
+++ b/ydb/core/wrappers/events/object_exists.h
@@ -4,6 +4,7 @@
 
 #include <ydb/core/base/events.h>
 #include <ydb/core/protos/flat_scheme_op.pb.h>
+#include <ydb/library/accessor/accessor.h>
 
 #include <contrib/libs/aws-sdk-cpp/aws-cpp-sdk-s3/include/aws/s3/model/HeadObjectRequest.h>
 #include <contrib/libs/aws-sdk-cpp/aws-cpp-sdk-s3/include/aws/s3/model/HeadObjectResult.h>
@@ -12,50 +13,22 @@
 
 namespace NKikimr::NWrappers::NExternalStorage {
 
-class TEvCheckObjectExistsRequest: public TEventLocal<TEvCheckObjectExistsRequest, EvCheckObjectExistsRequest> {
-public:
-    using TRequest = Aws::S3::Model::HeadObjectRequest;
+class TEvCheckObjectExistsRequest: public TGenericRequest<TEvCheckObjectExistsRequest,
+    EvCheckObjectExistsRequest, Aws::S3::Model::ListObjectsRequest> {
 private:
-    TRequest Request;
-    IRequestContext::TPtr RequestContext;
+    using TBase = TGenericRequest<TEvCheckObjectExistsRequest, EvCheckObjectExistsRequest, Aws::S3::Model::ListObjectsRequest>;
 public:
-    TEvCheckObjectExistsRequest(const TRequest& request, IRequestContext::TPtr requestContext)
-        : Request(request)
-        , RequestContext(requestContext) {
-
-    }
-    IRequestContext::TPtr GetRequestContext() const {
-        return RequestContext;
-    }
-    const TRequest& GetRequest() const {
-        return Request;
-    }
-    TRequest* operator->() {
-        return &Request;
-    }
+    using TBase::TBase;
 };
 
-class TEvCheckObjectExistsResponse: public TEventLocal<TEvCheckObjectExistsResponse, EvCheckObjectExistsResponse> {
-public:
-    using TRequest = Aws::S3::Model::HeadObjectRequest;
-    using TResult = Aws::S3::Model::HeadObjectResult;
-    using TOutcome = Aws::Utils::Outcome<TResult, Aws::S3::S3Error>;
-    using TKey = std::optional<TString>;
+class TEvCheckObjectExistsResponse: public TBaseGenericResponse<TEvCheckObjectExistsResponse,
+    EvCheckObjectExistsResponse, Aws::S3::Model::ListObjectsResult> {
 private:
-    IRequestContext::TPtr RequestContext;
-    const bool IsExistsFlag;
+    using TBase = TBaseGenericResponse<TEvCheckObjectExistsResponse, EvCheckObjectExistsResponse, Aws::S3::Model::ListObjectsResult>;
 public:
-    TEvCheckObjectExistsResponse(const TRequest& /*request*/, const TOutcome& outcome, IRequestContext::TPtr requestContext)
-        : RequestContext(requestContext)
-        , IsExistsFlag(outcome.IsSuccess() && !outcome.GetResult().GetDeleteMarker()) {
-
-    }
+    using TBase::TBase;
     bool IsExists() const {
-        return IsExistsFlag;
-    }
-    template <class T>
-    std::shared_ptr<T> GetRequestContextAs() const {
-        return dynamic_pointer_cast<T>(RequestContext);
+        return Result.IsSuccess() && Result.GetResult().GetContents().size();
     }
 };
 }
diff --git a/ydb/core/wrappers/fake_storage.cpp b/ydb/core/wrappers/fake_storage.cpp
index 147306aeb1b..5db1ee5944f 100644
--- a/ydb/core/wrappers/fake_storage.cpp
+++ b/ydb/core/wrappers/fake_storage.cpp
@@ -44,13 +44,14 @@ static bool TryParseRange(const TString& str, std::pair<ui64, ui64>& range) {
 }
 }
 
-void TFakeExternalStorage::Execute(TEvListObjectsRequest::TPtr& ev) const {
-    auto& awsPrefix = ev->Get()->GetRequest().GetPrefix();
+TEvListObjectsResponse::TResult TFakeExternalStorage::BuildListObjectsResult(const TEvListObjectsRequest::TRequest& request) const {
+    auto& bucket = GetBucket(AwsToString(request.GetBucket()));
+    auto& awsPrefix = request.GetPrefix();
     const TString prefix(awsPrefix.data(), awsPrefix.size());
     THolder<TEvListObjectsResponse> result;
     TGuard<TMutex> g(Mutex);
-    TEvListObjectsResponse::TResult awsResult;
-    for (auto&& i : Data) {
+    TEvListObjectsResponse::TAWSResult awsResult;
+    for (auto&& i : bucket) {
         if (!!prefix && !i.first.StartsWith(prefix)) {
             continue;
         }
@@ -60,31 +61,35 @@ void TFakeExternalStorage::Execute(TEvListObjectsRequest::TPtr& ev) const {
         awsResult.AddContents(std::move(objectMeta));
         break;
     }
-    awsResult.SetIsTruncated(Data.size() > 1);
-    TEvListObjectsResponse::TOutcome awsOutcome(awsResult);
-    result = MakeHolder<TEvListObjectsResponse>(awsOutcome);
+    awsResult.SetIsTruncated(bucket.GetSize() > 1);
+    return awsResult;
+}
+
+void TFakeExternalStorage::Execute(TEvListObjectsRequest::TPtr& ev) const {
+    auto awsResult = BuildListObjectsResult(ev->Get()->GetRequest());
+    auto result = MakeHolder<TEvListObjectsResponse>(awsResult);
     TlsActivationContext->ActorSystem()->Send(ev->Sender, result.Release());
 }
 
 void TFakeExternalStorage::Execute(TEvGetObjectRequest::TPtr& ev) const {
     TGuard<TMutex> g(Mutex);
-    auto& awsKey = ev->Get()->Request.GetKey();
-    const TString key(awsKey.data(), awsKey.size());
-    auto it = Data.find(key);
+    auto& bucket = GetBucket(AwsToString(ev->Get()->GetRequest().GetBucket()));
+    const TString key = AwsToString(ev->Get()->GetRequest().GetKey());
+    auto object = bucket.GetObject(key);
     TString data;
 
-    if (it != Data.end()) {
+    if (!!object) {
         Aws::S3::Model::GetObjectResult awsResult;
-        awsResult.SetETag(MD5::Calc(it->second));
-        data = it->second;
+        awsResult.SetETag(MD5::Calc(*object));
+        data = *object;
 
-        auto awsRange = ev->Get()->Request.GetRange();
+        auto awsRange = ev->Get()->GetRequest().GetRange();
         if (awsRange.size()) {
             const TString strRange(awsRange.data(), awsRange.size());
             std::pair<ui64, ui64> range;
             if (!TryParseRange(strRange, range)) {
                 Aws::Utils::Outcome<Aws::S3::Model::GetObjectResult, Aws::S3::S3Error> awsOutcome;
-                THolder<TEvGetObjectResponse> result(new TEvGetObjectResponse(key, awsOutcome, std::move(data)));
+                THolder<TEvGetObjectResponse> result(new TEvGetObjectResponse(key, std::move(awsOutcome), std::move(data)));
                 TlsActivationContext->ActorSystem()->Send(ev->Sender, result.Release());
                 return;
             } else {
@@ -93,41 +98,40 @@ void TFakeExternalStorage::Execute(TEvGetObjectRequest::TPtr& ev) const {
         }
 
         Aws::Utils::Outcome<Aws::S3::Model::GetObjectResult, Aws::S3::S3Error> awsOutcome(std::move(awsResult));
-        THolder<TEvGetObjectResponse> result(new TEvGetObjectResponse(key, awsOutcome, std::move(data)));
+        THolder<TEvGetObjectResponse> result(new TEvGetObjectResponse(key, std::move(awsOutcome), std::move(data)));
         TlsActivationContext->ActorSystem()->Send(ev->Sender, result.Release());
     } else {
         Aws::Utils::Outcome<Aws::S3::Model::GetObjectResult, Aws::S3::S3Error> awsOutcome;
-        THolder<TEvGetObjectResponse> result(new TEvGetObjectResponse(key, awsOutcome, std::move(data)));
+        THolder<TEvGetObjectResponse> result(new TEvGetObjectResponse(key, std::move(awsOutcome), std::move(data)));
         TlsActivationContext->ActorSystem()->Send(ev->Sender, result.Release());
     }
 }
 
 void TFakeExternalStorage::Execute(TEvHeadObjectRequest::TPtr& ev) const {
     TGuard<TMutex> g(Mutex);
-    auto& awsKey = ev->Get()->Request.GetKey();
-    const TString key(awsKey.data(), awsKey.size());
-
-    auto it = Data.find(key);
-    if (it != Data.end()) {
+    auto& bucket = GetBucket(AwsToString(ev->Get()->GetRequest().GetBucket()));
+    const TString key = AwsToString(ev->Get()->GetRequest().GetKey());
+    auto object = bucket.GetObject(key);
+    if (object) {
         Aws::S3::Model::HeadObjectResult awsResult;
-        awsResult.SetETag(MD5::Calc(it->second));
-        awsResult.SetContentLength(it->second.size());
+        awsResult.SetETag(MD5::Calc(*object));
+        awsResult.SetContentLength(object->size());
         Aws::Utils::Outcome<Aws::S3::Model::HeadObjectResult, Aws::S3::S3Error> awsOutcome(awsResult);
-        THolder<TEvHeadObjectResponse> result(new TEvHeadObjectResponse(key, awsOutcome));
+        THolder<TEvHeadObjectResponse> result(new TEvHeadObjectResponse(key, std::move(awsOutcome)));
         TlsActivationContext->ActorSystem()->Send(ev->Sender, result.Release());
     } else {
         Aws::Utils::Outcome<Aws::S3::Model::HeadObjectResult, Aws::S3::S3Error> awsOutcome;
-        THolder<TEvHeadObjectResponse> result(new TEvHeadObjectResponse(key, awsOutcome));
+        THolder<TEvHeadObjectResponse> result(new TEvHeadObjectResponse(key, std::move(awsOutcome)));
         TlsActivationContext->ActorSystem()->Send(ev->Sender, result.Release());
     }
 }
 
 void TFakeExternalStorage::Execute(TEvPutObjectRequest::TPtr& ev) const {
     TGuard<TMutex> g(Mutex);
+    const TString key = AwsToString(ev->Get()->GetRequest().GetKey());
+    auto& bucket = MutableBucket(AwsToString(ev->Get()->GetRequest().GetBucket()));
+    bucket.PutObject(key, ev->Get()->Body);
     Aws::S3::Model::PutObjectResult awsResult;
-    auto& awsKey = ev->Get()->Request.GetKey();
-    const TString key(awsKey.data(), awsKey.size());
-    Data[key] = ev->Get()->Body;
 
     THolder<TEvPutObjectResponse> result(new TEvPutObjectResponse(key, awsResult));
     TlsActivationContext->ActorSystem()->Send(ev->Sender, result.Release());
@@ -136,9 +140,9 @@ void TFakeExternalStorage::Execute(TEvPutObjectRequest::TPtr& ev) const {
 void TFakeExternalStorage::Execute(TEvDeleteObjectRequest::TPtr& ev) const {
     TGuard<TMutex> g(Mutex);
     Aws::S3::Model::DeleteObjectResult awsResult;
-    auto& awsKey = ev->Get()->Request.GetKey();
-    const TString key(awsKey.data(), awsKey.size());
-    Data.erase(key);
+    auto& bucket = MutableBucket(AwsToString(ev->Get()->GetRequest().GetBucket()));
+    const TString key = AwsToString(ev->Get()->GetRequest().GetKey());
+    bucket.Remove(key);
 
     THolder<TEvDeleteObjectResponse> result(new TEvDeleteObjectResponse(key, awsResult));
     TlsActivationContext->ActorSystem()->Send(ev->Sender, result.Release());
@@ -146,10 +150,11 @@ void TFakeExternalStorage::Execute(TEvDeleteObjectRequest::TPtr& ev) const {
 
 void TFakeExternalStorage::Execute(TEvDeleteObjectsRequest::TPtr& ev) const {
     TGuard<TMutex> g(Mutex);
+    auto& bucket = MutableBucket(AwsToString(ev->Get()->GetRequest().GetBucket()));
     Aws::S3::Model::DeleteObjectsResult awsResult;
     for (auto&& awsKey : ev->Get()->GetRequest().GetDelete().GetObjects()) {
-        const TString key(awsKey.GetKey().data(), awsKey.GetKey().size());
-        Data.erase(key);
+        const TString key = AwsToString(awsKey.GetKey());
+        bucket.Remove(key);
         Aws::S3::Model::DeletedObject dObject;
         dObject.WithKey(key);
         awsResult.AddDeleted(std::move(dObject));
@@ -173,21 +178,9 @@ void TFakeExternalStorage::Execute(TEvAbortMultipartUploadRequest::TPtr& /*ev*/)
 
 void TFakeExternalStorage::Execute(TEvCheckObjectExistsRequest::TPtr& ev) const {
     TGuard<TMutex> g(Mutex);
-    auto& awsKey = ev->Get()->GetRequest().GetKey();
-    const TString key(awsKey.data(), awsKey.size());
-
-    auto it = Data.find(key);
-    if (it != Data.end()) {
-        Aws::S3::Model::HeadObjectResult awsResult;
-        awsResult.SetETag(MD5::Calc(it->second));
-        awsResult.SetContentLength(it->second.size());
-        THolder<TEvCheckObjectExistsResponse> result(new TEvCheckObjectExistsResponse(ev->Get()->GetRequest(), awsResult, ev->Get()->GetRequestContext()));
-        TlsActivationContext->ActorSystem()->Send(ev->Sender, result.Release());
-    } else {
-        Aws::Utils::Outcome<Aws::S3::Model::HeadObjectResult, Aws::S3::S3Error> awsOutcome;
-        THolder<TEvCheckObjectExistsResponse> result(new TEvCheckObjectExistsResponse(ev->Get()->GetRequest(), awsOutcome, ev->Get()->GetRequestContext()));
-        TlsActivationContext->ActorSystem()->Send(ev->Sender, result.Release());
-    }
+    auto awsResult = BuildListObjectsResult(ev->Get()->GetRequest());
+    THolder<TEvCheckObjectExistsResponse> result(new TEvCheckObjectExistsResponse(awsResult, ev->Get()->GetRequestContext()));
+    TlsActivationContext->ActorSystem()->Send(ev->Sender, result.Release());
 
 }
 }
diff --git a/ydb/core/wrappers/fake_storage.h b/ydb/core/wrappers/fake_storage.h
index d14a0606b8e..09c23ee7a2a 100644
--- a/ydb/core/wrappers/fake_storage.h
+++ b/ydb/core/wrappers/fake_storage.h
@@ -13,15 +13,79 @@
 #include <util/string/printf.h>
 
 namespace NKikimr::NWrappers::NExternalStorage {
+class TFakeBucketStorage {
+private:
+    mutable TMutex Mutex;
+    TMap<TString, TString> Data;
+public:
+    TMap<TString, TString>::const_iterator begin() const {
+        return Data.begin();
+    }
+    TMap<TString, TString>::const_iterator end() const {
+        return Data.end();
+    }
+    ui32 GetSize() const {
+        return Data.size();
+    }
+    void PutObject(const TString& objectId, const TString& data) {
+        TGuard<TMutex> g(Mutex);
+        Data[objectId] = data;
+    }
+    std::optional<TString> GetObject(const TString& objectId) const {
+        TGuard<TMutex> g(Mutex);
+        auto it = Data.find(objectId);
+        if (it == Data.end()) {
+            return {};
+        }
+        return it->second;
+    }
+    void Remove(const TString& objectId) {
+        Data.erase(objectId);
+    }
+};
+
 class TFakeExternalStorage {
 private:
     mutable TMutex Mutex;
-    mutable TMap<TString, TString> Data;
+    mutable TMap<TString, TFakeBucketStorage> BucketStorages;
+    TEvListObjectsResponse::TResult BuildListObjectsResult(const TEvListObjectsRequest::TRequest& request) const;
+
+    TString AwsToString(const Aws::String& awsString) const {
+        TString result(awsString.data(), awsString.size());
+        return result;
+    }
 public:
     TFakeExternalStorage() = default;
-    TMap<TString, TString> GetData() const {
+    const TFakeBucketStorage& GetBucket(const TString& bucketId) const {
+        TGuard<TMutex> g(Mutex);
+        auto it = BucketStorages.find(bucketId);
+        if (it == BucketStorages.end()) {
+            it = BucketStorages.emplace(bucketId, TFakeBucketStorage()).first;
+        }
+        return it->second;
+    }
+
+    TFakeBucketStorage& MutableBucket(const TString& bucketId) const {
+        TGuard<TMutex> g(Mutex);
+        auto it = BucketStorages.find(bucketId);
+        if (it == BucketStorages.end()) {
+            it = BucketStorages.emplace(bucketId, TFakeBucketStorage()).first;
+        }
+        return it->second;
+    }
+
+    ui32 GetSize() const {
+        ui32 result = 0;
         TGuard<TMutex> g(Mutex);
-        return Data;
+        for (auto&& i : BucketStorages) {
+            result += i.second.GetSize();
+        }
+        return result;
+    }
+
+    ui32 GetBucketsCount() const {
+        TGuard<TMutex> g(Mutex);
+        return BucketStorages.size();
     }
     void Execute(TEvListObjectsRequest::TPtr& ev) const;
     void Execute(TEvGetObjectRequest::TPtr& ev) const;
@@ -37,39 +101,56 @@ public:
 };
 
 class TFakeExternalStorageOperator: public IExternalStorageOperator {
+private:
+    const TString Bucket;
 public:
-    TFakeExternalStorageOperator() = default;
+    TFakeExternalStorageOperator(const TString& bucket)
+        : Bucket(bucket)
+    {
+
+    }
     virtual void Execute(TEvCheckObjectExistsRequest::TPtr& ev) const override {
+        ev->Get()->MutableRequest().WithBucket(Bucket);
         Singleton<TFakeExternalStorage>()->Execute(ev);
     }
     virtual void Execute(TEvListObjectsRequest::TPtr& ev) const override {
+        ev->Get()->MutableRequest().WithBucket(Bucket);
         Singleton<TFakeExternalStorage>()->Execute(ev);
     }
     virtual void Execute(TEvGetObjectRequest::TPtr& ev) const override {
+        ev->Get()->MutableRequest().WithBucket(Bucket);
         Singleton<TFakeExternalStorage>()->Execute(ev);
     }
     virtual void Execute(TEvHeadObjectRequest::TPtr& ev) const override {
+        ev->Get()->MutableRequest().WithBucket(Bucket);
         Singleton<TFakeExternalStorage>()->Execute(ev);
     }
     virtual void Execute(TEvPutObjectRequest::TPtr& ev) const override {
+        ev->Get()->MutableRequest().WithBucket(Bucket);
         Singleton<TFakeExternalStorage>()->Execute(ev);
     }
     virtual void Execute(TEvDeleteObjectRequest::TPtr& ev) const override {
+        ev->Get()->MutableRequest().WithBucket(Bucket);
         Singleton<TFakeExternalStorage>()->Execute(ev);
     }
     virtual void Execute(TEvDeleteObjectsRequest::TPtr& ev) const override {
+        ev->Get()->MutableRequest().WithBucket(Bucket);
         Singleton<TFakeExternalStorage>()->Execute(ev);
     }
     virtual void Execute(TEvCreateMultipartUploadRequest::TPtr& ev) const override {
+        ev->Get()->MutableRequest().WithBucket(Bucket);
         Singleton<TFakeExternalStorage>()->Execute(ev);
     }
     virtual void Execute(TEvUploadPartRequest::TPtr& ev) const override {
+        ev->Get()->MutableRequest().WithBucket(Bucket);
         Singleton<TFakeExternalStorage>()->Execute(ev);
     }
     virtual void Execute(TEvCompleteMultipartUploadRequest::TPtr& ev) const override {
+        ev->Get()->MutableRequest().WithBucket(Bucket);
         Singleton<TFakeExternalStorage>()->Execute(ev);
     }
     virtual void Execute(TEvAbortMultipartUploadRequest::TPtr& ev) const override {
+        ev->Get()->MutableRequest().WithBucket(Bucket);
         Singleton<TFakeExternalStorage>()->Execute(ev);
     }
 };
diff --git a/ydb/core/wrappers/fake_storage_config.cpp b/ydb/core/wrappers/fake_storage_config.cpp
index 29da4e8c244..0d2f9650f2a 100644
--- a/ydb/core/wrappers/fake_storage_config.cpp
+++ b/ydb/core/wrappers/fake_storage_config.cpp
@@ -10,7 +10,7 @@ TString TFakeExternalStorageConfig::DoGetStorageId() const {
 }
 
 IExternalStorageOperator::TPtr TFakeExternalStorageConfig::DoConstructStorageOperator() const {
-    return std::make_shared<TFakeExternalStorageOperator>();
+    return std::make_shared<TFakeExternalStorageOperator>(Bucket);
 }
 }
 
diff --git a/ydb/core/wrappers/fake_storage_config.h b/ydb/core/wrappers/fake_storage_config.h
index 01a62b81a34..e6ce528a7c5 100644
--- a/ydb/core/wrappers/fake_storage_config.h
+++ b/ydb/core/wrappers/fake_storage_config.h
@@ -12,10 +12,17 @@
 namespace NKikimr::NWrappers::NExternalStorage {
 
 class TFakeExternalStorageConfig: public IExternalStorageConfig {
+private:
+    const TString Bucket;
 protected:
     virtual TString DoGetStorageId() const override;
     virtual IExternalStorageOperator::TPtr DoConstructStorageOperator() const override;
 public:
+    TFakeExternalStorageConfig(const TString& bucket)
+        : Bucket(bucket)
+    {
+
+    }
 };
 } // NKikimr::NWrappers::NExternalStorage
 
diff --git a/ydb/core/wrappers/s3_storage.cpp b/ydb/core/wrappers/s3_storage.cpp
index 86cb5a86f21..55912060365 100644
--- a/ydb/core/wrappers/s3_storage.cpp
+++ b/ydb/core/wrappers/s3_storage.cpp
@@ -120,9 +120,9 @@ private:
 public:
     using TBase::Send;
     using TBase::TBase;
-    void Reply(const typename TBase::TRequest& request, const typename TBase::TOutcome& outcome) const {
+    void Reply(const typename TBase::TRequest& /*request*/, const typename TBase::TOutcome& outcome) const {
         Y_VERIFY(!std::exchange(TBase::Replied, true), "Double-reply");
-        Send(MakeHolder<TEvCheckObjectExistsResponse>(request, outcome, RequestContext).Release());
+        Send(MakeHolder<TEvCheckObjectExistsResponse>(outcome, RequestContext).Release());
     }
 };
 
@@ -224,7 +224,7 @@ public:
     using TContextBase<TEvRequest, TEvResponse>::TContextBase;
 
     const TRequest& PrepareRequest(typename TEvRequest::TPtr& ev) override {
-        auto& request = ev->Get()->Request;
+        auto& request = ev->Get()->MutableRequest();
 
         Buffer = std::move(ev->Get()->Body);
         request.SetBody(MakeShared<DefaultUnderlyingStream>("StreamContext",
@@ -253,7 +253,7 @@ void TS3ExternalStorage::Execute(TEvGetObjectRequest::TPtr& ev) const {
 
 void TS3ExternalStorage::Execute(TEvCheckObjectExistsRequest::TPtr& ev) const {
     Call<TEvCheckObjectExistsRequest, TEvCheckObjectExistsResponse, TContextBase>(
-        ev, &S3Client::HeadObjectAsync);
+        ev, &S3Client::ListObjectsAsync);
 }
 
 void TS3ExternalStorage::Execute(TEvListObjectsRequest::TPtr& ev) const {
diff --git a/ydb/core/wrappers/s3_storage.h b/ydb/core/wrappers/s3_storage.h
index 11009c2171a..c5f239b1a42 100644
--- a/ydb/core/wrappers/s3_storage.h
+++ b/ydb/core/wrappers/s3_storage.h
@@ -32,6 +32,7 @@ private:
     THolder<Aws::S3::S3Client> Client;
     const Aws::Client::ClientConfiguration Config;
     const Aws::Auth::AWSCredentials Credentials;
+    const TString Bucket;
 
     template <typename TRequest, typename TOutcome>
     using THandler = std::function<void(const Aws::S3::S3Client*, const TRequest&, const TOutcome&, const std::shared_ptr<const Aws::Client::AsyncCallerContext>&)>;
@@ -42,6 +43,7 @@ private:
     template <typename TEvRequest, typename TEvResponse, template <typename...> typename TContext>
     void Call(typename TEvRequest::TPtr& ev, TFunc<typename TEvRequest::TRequest, typename TEvResponse::TOutcome> func) const {
         using TCtx = TContext<TEvRequest, TEvResponse>;
+        ev->Get()->MutableRequest().WithBucket(Bucket);
 
         auto ctx = std::make_shared<TCtx>(TlsActivationContext->ActorSystem(), ev->Sender, ev->Get()->GetRequestContext());
         auto callback = [](
@@ -64,10 +66,12 @@ private:
     }
 
 public:
-    TS3ExternalStorage(const Aws::Client::ClientConfiguration& config, const Aws::Auth::AWSCredentials& credentials)
+    TS3ExternalStorage(const Aws::Client::ClientConfiguration& config, const Aws::Auth::AWSCredentials& credentials, const TString& bucket)
         : Client(new Aws::S3::S3Client(credentials, config))
         , Config(config)
-        , Credentials(credentials) {
+        , Credentials(credentials)
+        , Bucket(bucket)
+    {
     }
 
     ~TS3ExternalStorage();
diff --git a/ydb/core/wrappers/s3_storage_config.cpp b/ydb/core/wrappers/s3_storage_config.cpp
index f0ce4964274..0032e45a519 100644
--- a/ydb/core/wrappers/s3_storage_config.cpp
+++ b/ydb/core/wrappers/s3_storage_config.cpp
@@ -183,8 +183,30 @@ TString TS3ExternalStorageConfig::DoGetStorageId() const {
 }
 
 IExternalStorageOperator::TPtr TS3ExternalStorageConfig::DoConstructStorageOperator() const {
-    return std::make_shared<TS3ExternalStorage>(Config, Credentials);
+    return std::make_shared<TS3ExternalStorage>(Config, Credentials, Bucket);
 }
+
+TS3ExternalStorageConfig::TS3ExternalStorageConfig(const Ydb::Import::ImportFromS3Settings& settings): Config(ConfigFromSettings(settings))
+, Credentials(CredentialsFromSettings(settings))
+{
+    Bucket = settings.bucket();
+}
+
+TS3ExternalStorageConfig::TS3ExternalStorageConfig(const Aws::Auth::AWSCredentials& credentials,
+    const Aws::Client::ClientConfiguration& config, const TString& bucket)
+    : Config(config)
+    , Credentials(credentials)
+{
+    Bucket = bucket;
+}
+
+TS3ExternalStorageConfig::TS3ExternalStorageConfig(const NKikimrSchemeOp::TS3Settings& settings)
+    : Config(ConfigFromSettings(settings))
+    , Credentials(CredentialsFromSettings(settings))
+{
+    Bucket = settings.GetBucket();
+}
+
 }
 
 #endif // KIKIMR_DISABLE_S3_OPS
diff --git a/ydb/core/wrappers/s3_storage_config.h b/ydb/core/wrappers/s3_storage_config.h
index 7ecefab799e..07fb87b9fb3 100644
--- a/ydb/core/wrappers/s3_storage_config.h
+++ b/ydb/core/wrappers/s3_storage_config.h
@@ -6,6 +6,7 @@
 
 #include <ydb/core/base/events.h>
 #include <ydb/core/protos/flat_scheme_op.pb.h>
+#include <ydb/library/accessor/accessor.h>
 #include <ydb/public/api/protos/ydb_import.pb.h>
 
 #include <contrib/libs/aws-sdk-cpp/aws-cpp-sdk-core/include/aws/core/auth/AWSCredentials.h>
@@ -24,6 +25,7 @@ struct TS3User {
 
 class TS3ExternalStorageConfig: public IExternalStorageConfig, TS3User {
 private:
+    YDB_READONLY_DEF(TString, Bucket);
     Aws::Client::ClientConfiguration Config;
     const Aws::Auth::AWSCredentials Credentials;
 
@@ -44,21 +46,9 @@ public:
         return Config;
     }
 
-    TS3ExternalStorageConfig(const NKikimrSchemeOp::TS3Settings& settings)
-        : Config(ConfigFromSettings(settings))
-        , Credentials(CredentialsFromSettings(settings)) {
-
-    }
-    TS3ExternalStorageConfig(const Ydb::Import::ImportFromS3Settings& settings)
-        : Config(ConfigFromSettings(settings))
-        , Credentials(CredentialsFromSettings(settings)) {
-
-    }
-    TS3ExternalStorageConfig(const Aws::Auth::AWSCredentials& credentials, const Aws::Client::ClientConfiguration& config)
-        : Config(config)
-        , Credentials(credentials) {
-
-    }
+    TS3ExternalStorageConfig(const NKikimrSchemeOp::TS3Settings& settings);
+    TS3ExternalStorageConfig(const Ydb::Import::ImportFromS3Settings& settings);
+    TS3ExternalStorageConfig(const Aws::Auth::AWSCredentials& credentials, const Aws::Client::ClientConfiguration& config, const TString& bucket);
 };
 } // NKikimr::NWrappers::NExternalStorage
 
diff --git a/ydb/core/wrappers/s3_wrapper.cpp b/ydb/core/wrappers/s3_wrapper.cpp
index 42474eb605f..84d7479dd63 100644
--- a/ydb/core/wrappers/s3_wrapper.cpp
+++ b/ydb/core/wrappers/s3_wrapper.cpp
@@ -23,47 +23,9 @@ namespace NKikimr::NWrappers {
 namespace NExternalStorage {
 
 class TS3Wrapper: public TActor<TS3Wrapper> {
-    void Handle(TEvListObjectsRequest::TPtr& ev) {
-        CSOperator->Execute(ev);
-    }
-
-    void Handle(TEvGetObjectRequest::TPtr& ev) {
-        CSOperator->Execute(ev);
-    }
-
-    void Handle(TEvCheckObjectExistsRequest::TPtr& ev) {
-        CSOperator->Execute(ev);
-    }
-
-    void Handle(TEvHeadObjectRequest::TPtr& ev) {
-        CSOperator->Execute(ev);
-    }
-
-    void Handle(TEvPutObjectRequest::TPtr& ev) {
-        CSOperator->Execute(ev);
-    }
-
-    void Handle(TEvDeleteObjectRequest::TPtr& ev) {
-        CSOperator->Execute(ev);
-    }
-
-    void Handle(TEvDeleteObjectsRequest::TPtr& ev) {
-        CSOperator->Execute(ev);
-    }
-
-    void Handle(TEvCreateMultipartUploadRequest::TPtr& ev) {
-        CSOperator->Execute(ev);
-    }
-
-    void Handle(TEvUploadPartRequest::TPtr& ev) {
-        CSOperator->Execute(ev);
-    }
-
-    void Handle(TEvCompleteMultipartUploadRequest::TPtr& ev) {
-        CSOperator->Execute(ev);
-    }
 
-    void Handle(TEvAbortMultipartUploadRequest::TPtr& ev) {
+    template <class T>
+    void Handle(T& ev) {
         CSOperator->Execute(ev);
     }
 
@@ -74,7 +36,9 @@ public:
 
     explicit TS3Wrapper(IExternalStorageOperator::TPtr csOperator)
         : TActor(&TThis::StateWork)
-        , CSOperator(csOperator) {
+        , CSOperator(csOperator)
+    {
+        Y_VERIFY(!!CSOperator, "not initialized operator. incorrect config.");
     }
 
     virtual ~TS3Wrapper() = default;
diff --git a/ydb/core/wrappers/s3_wrapper_ut.cpp b/ydb/core/wrappers/s3_wrapper_ut.cpp
index 90724831c92..b864e183010 100644
--- a/ydb/core/wrappers/s3_wrapper_ut.cpp
+++ b/ydb/core/wrappers/s3_wrapper_ut.cpp
@@ -43,7 +43,7 @@ public:
         Runtime = MakeHolder<TTestBasicRuntime>();
         Runtime->Initialize(TAppPrepare().Unwrap());
         Runtime->SetLogPriority(NKikimrServices::S3_WRAPPER, NLog::PRI_DEBUG);
-        NWrappers::IExternalStorageConfig::TPtr config = std::make_shared<NExternalStorage::TS3ExternalStorageConfig>(Aws::Auth::AWSCredentials(), MakeClientConfig(*Port));
+        NWrappers::IExternalStorageConfig::TPtr config = std::make_shared<NExternalStorage::TS3ExternalStorageConfig>(Aws::Auth::AWSCredentials(), MakeClientConfig(*Port), "TEST");
         Wrapper = Runtime->Register(NWrappers::CreateS3Wrapper(config->ConstructStorageOperator()));
     }
 
diff --git a/ydb/services/metadata/ds_table/accessor_subscribe.cpp b/ydb/services/metadata/ds_table/accessor_subscribe.cpp
index 93a41f8c481..6d01ae8ca2c 100644
--- a/ydb/services/metadata/ds_table/accessor_subscribe.cpp
+++ b/ydb/services/metadata/ds_table/accessor_subscribe.cpp
@@ -23,7 +23,7 @@ void TDSAccessorNotifier::Handle(TEvSubscribe::TPtr& ev) {
             ALS_ERROR(NKikimrServices::METADATA_PROVIDER) << "cannot construct snapshot";
             return;
         }
-        Send(ev->Get()->GetSubscriberId(), new TEvRefreshSubscriberData(snapshot));
+        Sender<TEvRefreshSubscriberData>(snapshot).SendTo(ev->Get()->GetSubscriberId());
     }
 }
 
diff --git a/ydb/services/metadata/ds_table/service.cpp b/ydb/services/metadata/ds_table/service.cpp
index d75d258450b..faa76a15878 100644
--- a/ydb/services/metadata/ds_table/service.cpp
+++ b/ydb/services/metadata/ds_table/service.cpp
@@ -20,7 +20,11 @@ void TService::Handle(TEvSubscribeExternal::TPtr& ev) {
         THolder<TExternalData> actor = MakeHolder<TExternalData>(Config, ev->Get()->GetSnapshotParser());
         it = Accessors.emplace(ev->Get()->GetSnapshotParser()->GetSnapshotId(), Register(actor.Release())).first;
     }
-    Send<TEvSubscribe>(it->second, ev->Sender);
+    if (!!ev->Get()->GetSubscriberId()) {
+        Send<TEvSubscribe>(it->second, ev->Get()->GetSubscriberId());
+    } else {
+        Send<TEvSubscribe>(it->second, ev->Sender);
+    }
 }
 
 void TService::Handle(TEvUnsubscribeExternal::TPtr& ev) {
diff --git a/ydb/services/metadata/service.h b/ydb/services/metadata/service.h
index 72800a06d21..888ec5763b4 100644
--- a/ydb/services/metadata/service.h
+++ b/ydb/services/metadata/service.h
@@ -7,9 +7,12 @@ namespace NKikimr::NMetadataProvider {
 class TEvSubscribeExternal: public NActors::TEventLocal<TEvSubscribeExternal, EEvSubscribe::EvSubscribeExternal> {
 private:
     YDB_READONLY_DEF(ISnapshotParser::TPtr, SnapshotParser);
+    YDB_READONLY_DEF(NActors::TActorId, SubscriberId);
 public:
-    TEvSubscribeExternal(ISnapshotParser::TPtr parser)
-        : SnapshotParser(parser) {
+    TEvSubscribeExternal(ISnapshotParser::TPtr parser, const NActors::TActorId& subscriberId = {})
+        : SnapshotParser(parser)
+        , SubscriberId(subscriberId)
+    {
         Y_VERIFY(!!SnapshotParser);
     }
 };