TRowVersion -> TSnapshot (#921)

9 files changed, 71 insertions, 74 deletions

diff --git a/ydb/core/tx/columnshard/columnshard.cpp b/ydb/core/tx/columnshard/columnshard.cpp
index ba53d51fac..8d19c31673 100644
--- a/ydb/core/tx/columnshard/columnshard.cpp
+++ b/ydb/core/tx/columnshard/columnshard.cpp
@@ -258,7 +258,7 @@ ui64 TColumnShard::MemoryUsage() const {
         CommitsInFlight.size() * sizeof(TCommitMeta) +
         LongTxWrites.size() * (sizeof(TWriteId) + sizeof(TLongTxWriteInfo)) +
         LongTxWritesByUniqueId.size() * (sizeof(TULID) + sizeof(void*)) +
-        (WaitingReads.size() + WaitingScans.size()) * (sizeof(TRowVersion) + sizeof(void*)) +
+        (WaitingReads.size() + WaitingScans.size()) * (sizeof(NOlap::TSnapshot) + sizeof(void*)) +
         TabletCounters->Simple()[COUNTER_PREPARED_RECORDS].Get() * sizeof(NOlap::TInsertedData) +
         TabletCounters->Simple()[COUNTER_COMMITTED_RECORDS].Get() * sizeof(NOlap::TInsertedData);
     memory += TablesManager.GetMemoryUsage();
diff --git a/ydb/core/tx/columnshard/columnshard__progress_tx.cpp b/ydb/core/tx/columnshard/columnshard__progress_tx.cpp
index 522f6a6301..d8450d124a 100644
--- a/ydb/core/tx/columnshard/columnshard__progress_tx.cpp
+++ b/ydb/core/tx/columnshard/columnshard__progress_tx.cpp
@@ -86,7 +86,7 @@ public:
                 case NKikimrTxColumnShard::TX_KIND_SCHEMA:
                 {
                     auto& meta = Self->AltersInFlight.at(txId);
-                    Self->RunSchemaTx(meta.Body, TRowVersion(step, txId), txc);
+                    Self->RunSchemaTx(meta.Body, NOlap::TSnapshot(step, txId), txc);
                     Self->ProtectSchemaSeqNo(meta.Body.GetSeqNo(), txc);
                     for (TActorId subscriber : meta.NotifySubscribers) {
                         TxEvents.emplace_back(subscriber, 0,
diff --git a/ydb/core/tx/columnshard/columnshard__read.cpp b/ydb/core/tx/columnshard/columnshard__read.cpp
index c2816e27e8..ae4455099c 100644
--- a/ydb/core/tx/columnshard/columnshard__read.cpp
+++ b/ydb/core/tx/columnshard/columnshard__read.cpp
@@ -149,13 +149,13 @@ void TColumnShard::Handle(TEvColumnShard::TEvRead::TPtr& ev, const TActorContext
     LastAccessTime = TAppData::TimeProvider->Now();
 
     const auto* msg = ev->Get();
-    TRowVersion readVersion(msg->Record.GetPlanStep(), msg->Record.GetTxId());
-    TRowVersion maxReadVersion = GetMaxReadVersion();
+    NOlap::TSnapshot readVersion(msg->Record.GetPlanStep(), msg->Record.GetTxId());
+    NOlap::TSnapshot maxReadVersion = GetMaxReadVersion();
     LOG_S_DEBUG("Read at tablet " << TabletID() << " version=" << readVersion << " readable=" << maxReadVersion);
 
     if (maxReadVersion < readVersion) {
         WaitingReads.emplace(readVersion, std::move(ev));
-        WaitPlanStep(readVersion.Step);
+        WaitPlanStep(readVersion.GetPlanStep());
         return;
     }
 
diff --git a/ydb/core/tx/columnshard/columnshard__scan.cpp b/ydb/core/tx/columnshard/columnshard__scan.cpp
index 43e5d0115d..114881eb4e 100644
--- a/ydb/core/tx/columnshard/columnshard__scan.cpp
+++ b/ydb/core/tx/columnshard/columnshard__scan.cpp
@@ -878,8 +878,8 @@ void TColumnShard::Handle(TEvColumnShard::TEvScan::TPtr& ev, const TActorContext
     const auto& scanId = record.GetScanId();
     const auto& snapshot = record.GetSnapshot();
 
-    TRowVersion readVersion(snapshot.GetStep(), snapshot.GetTxId());
-    TRowVersion maxReadVersion = GetMaxReadVersion();
+    NOlap::TSnapshot readVersion(snapshot.GetStep(), snapshot.GetTxId());
+    NOlap::TSnapshot maxReadVersion = GetMaxReadVersion();
 
     LOG_S_DEBUG("EvScan txId: " << txId
         << " scanId: " << scanId
@@ -889,7 +889,7 @@ void TColumnShard::Handle(TEvColumnShard::TEvScan::TPtr& ev, const TActorContext
 
     if (maxReadVersion < readVersion) {
         WaitingScans.emplace(readVersion, std::move(ev));
-        WaitPlanStep(readVersion.Step);
+        WaitPlanStep(readVersion.GetPlanStep());
         return;
     }
 
diff --git a/ydb/core/tx/columnshard/columnshard_impl.cpp b/ydb/core/tx/columnshard/columnshard_impl.cpp
index bd93759cc4..4098d2b00c 100644
--- a/ydb/core/tx/columnshard/columnshard_impl.cpp
+++ b/ydb/core/tx/columnshard/columnshard_impl.cpp
@@ -256,10 +256,10 @@ void TColumnShard::SendWaitPlanStep(ui64 step) {
 
 void TColumnShard::RescheduleWaitingReads() {
     ui64 minWaitingStep = Max<ui64>();
-    TRowVersion maxReadVersion = GetMaxReadVersion();
+    NOlap::TSnapshot maxReadVersion = GetMaxReadVersion();
     for (auto it = WaitingReads.begin(); it != WaitingReads.end();) {
         if (maxReadVersion < it->first) {
-            minWaitingStep = Min(minWaitingStep, it->first.Step);
+            minWaitingStep = Min(minWaitingStep, it->first.GetPlanStep());
             break;
         }
         TActivationContext::Send(it->second.Release());
@@ -267,7 +267,7 @@ void TColumnShard::RescheduleWaitingReads() {
     }
     for (auto it = WaitingScans.begin(); it != WaitingScans.end();) {
         if (maxReadVersion < it->first) {
-            minWaitingStep = Min(minWaitingStep, it->first.Step);
+            minWaitingStep = Min(minWaitingStep, it->first.GetPlanStep());
             break;
         }
         TActivationContext::Send(it->second.Release());
@@ -278,18 +278,19 @@ void TColumnShard::RescheduleWaitingReads() {
     }
 }
 
-TRowVersion TColumnShard::GetMaxReadVersion() const {
+NOlap::TSnapshot TColumnShard::GetMaxReadVersion() const {
     auto plannedTx = ProgressTxController->GetPlannedTx();
     if (plannedTx) {
         // We may only read just before the first transaction in the queue
-        return TRowVersion(plannedTx->Step, plannedTx->TxId).Prev();
+        auto maxReadVersion = TRowVersion(plannedTx->Step, plannedTx->TxId).Prev();
+        return NOlap::TSnapshot(maxReadVersion.Step, maxReadVersion.TxId);
     }
     ui64 step = LastPlannedStep;
     if (MediatorTimeCastEntry) {
         ui64 mediatorStep = MediatorTimeCastEntry->Get(TabletID());
         step = Max(step, mediatorStep);
     }
-    return TRowVersion(step, Max<ui64>());
+    return NOlap::TSnapshot(step, Max<ui64>());
 }
 
 ui64 TColumnShard::GetOutdatedStep() const {
@@ -450,7 +451,7 @@ void TColumnShard::ProtectSchemaSeqNo(const NKikimrTxColumnShard::TSchemaSeqNo&
     }
 }
 
-void TColumnShard::RunSchemaTx(const NKikimrTxColumnShard::TSchemaTxBody& body, const TRowVersion& version,
+void TColumnShard::RunSchemaTx(const NKikimrTxColumnShard::TSchemaTxBody& body, const NOlap::TSnapshot& version,
                                NTabletFlatExecutor::TTransactionContext& txc) {
     switch (body.TxBody_case()) {
         case NKikimrTxColumnShard::TSchemaTxBody::kInitShard: {
@@ -483,7 +484,7 @@ void TColumnShard::RunSchemaTx(const NKikimrTxColumnShard::TSchemaTxBody& body,
     Y_ABORT("Unsupported schema tx type");
 }
 
-void TColumnShard::RunInit(const NKikimrTxColumnShard::TInitShard& proto, const TRowVersion& version,
+void TColumnShard::RunInit(const NKikimrTxColumnShard::TInitShard& proto, const NOlap::TSnapshot& version,
                            NTabletFlatExecutor::TTransactionContext& txc) {
     Y_UNUSED(version);
 
@@ -504,7 +505,7 @@ void TColumnShard::RunInit(const NKikimrTxColumnShard::TInitShard& proto, const
     }
 }
 
-void TColumnShard::RunEnsureTable(const NKikimrTxColumnShard::TCreateTable& tableProto, const TRowVersion& version,
+void TColumnShard::RunEnsureTable(const NKikimrTxColumnShard::TCreateTable& tableProto, const NOlap::TSnapshot& version,
                                   NTabletFlatExecutor::TTransactionContext& txc) {
     NIceDb::TNiceDb db(txc.DB);
 
@@ -560,7 +561,7 @@ void TColumnShard::RunEnsureTable(const NKikimrTxColumnShard::TCreateTable& tabl
     SetCounter(COUNTER_TABLE_TTLS, TablesManager.GetTtl().PathsCount());
 }
 
-void TColumnShard::RunAlterTable(const NKikimrTxColumnShard::TAlterTable& alterProto, const TRowVersion& version,
+void TColumnShard::RunAlterTable(const NKikimrTxColumnShard::TAlterTable& alterProto, const NOlap::TSnapshot& version,
                                  NTabletFlatExecutor::TTransactionContext& txc) {
     NIceDb::TNiceDb db(txc.DB);
 
@@ -593,7 +594,7 @@ void TColumnShard::RunAlterTable(const NKikimrTxColumnShard::TAlterTable& alterP
     TablesManager.AddTableVersion(pathId, version, tableVerProto, db);
 }
 
-void TColumnShard::RunDropTable(const NKikimrTxColumnShard::TDropTable& dropProto, const TRowVersion& version,
+void TColumnShard::RunDropTable(const NKikimrTxColumnShard::TDropTable& dropProto, const NOlap::TSnapshot& version,
                                 NTabletFlatExecutor::TTransactionContext& txc) {
     NIceDb::TNiceDb db(txc.DB);
 
@@ -614,7 +615,7 @@ void TColumnShard::RunDropTable(const NKikimrTxColumnShard::TDropTable& dropProt
     TryAbortWrites(db, dbTable, std::move(writesToAbort));
 }
 
-void TColumnShard::RunAlterStore(const NKikimrTxColumnShard::TAlterStore& proto, const TRowVersion& version,
+void TColumnShard::RunAlterStore(const NKikimrTxColumnShard::TAlterStore& proto, const NOlap::TSnapshot& version,
                                  NTabletFlatExecutor::TTransactionContext& txc) {
     NIceDb::TNiceDb db(txc.DB);
 
diff --git a/ydb/core/tx/columnshard/columnshard_impl.h b/ydb/core/tx/columnshard/columnshard_impl.h
index e9c4062061..cbd33a169c 100644
--- a/ydb/core/tx/columnshard/columnshard_impl.h
+++ b/ydb/core/tx/columnshard/columnshard_impl.h
@@ -428,8 +428,8 @@ private:
     THashMap<TWriteId, TLongTxWriteInfo> LongTxWrites;
     using TPartsForLTXShard = THashMap<ui32, TLongTxWriteInfo*>;
     THashMap<TULID, TPartsForLTXShard> LongTxWritesByUniqueId;
-    TMultiMap<TRowVersion, TEvColumnShard::TEvRead::TPtr> WaitingReads;
-    TMultiMap<TRowVersion, TEvColumnShard::TEvScan::TPtr> WaitingScans;
+    TMultiMap<NOlap::TSnapshot, TEvColumnShard::TEvRead::TPtr> WaitingReads;
+    TMultiMap<NOlap::TSnapshot, TEvColumnShard::TEvScan::TPtr> WaitingScans;
     TBackgroundController BackgroundController;
     TSettings Settings;
     TLimits Limits;
@@ -442,7 +442,7 @@ private:
     bool WaitPlanStep(ui64 step);
     void SendWaitPlanStep(ui64 step);
     void RescheduleWaitingReads();
-    TRowVersion GetMaxReadVersion() const;
+    NOlap::TSnapshot GetMaxReadVersion() const;
     ui64 GetMinReadStep() const;
     ui64 GetOutdatedStep() const;
 
@@ -465,12 +465,12 @@ private:
     void UpdateSchemaSeqNo(const TMessageSeqNo& seqNo, NTabletFlatExecutor::TTransactionContext& txc);
     void ProtectSchemaSeqNo(const NKikimrTxColumnShard::TSchemaSeqNo& seqNoProto, NTabletFlatExecutor::TTransactionContext& txc);
 
-    void RunSchemaTx(const NKikimrTxColumnShard::TSchemaTxBody& body, const TRowVersion& version, NTabletFlatExecutor::TTransactionContext& txc);
-    void RunInit(const NKikimrTxColumnShard::TInitShard& body, const TRowVersion& version, NTabletFlatExecutor::TTransactionContext& txc);
-    void RunEnsureTable(const NKikimrTxColumnShard::TCreateTable& body, const TRowVersion& version, NTabletFlatExecutor::TTransactionContext& txc);
-    void RunAlterTable(const NKikimrTxColumnShard::TAlterTable& body, const TRowVersion& version, NTabletFlatExecutor::TTransactionContext& txc);
-    void RunDropTable(const NKikimrTxColumnShard::TDropTable& body, const TRowVersion& version, NTabletFlatExecutor::TTransactionContext& txc);
-    void RunAlterStore(const NKikimrTxColumnShard::TAlterStore& body, const TRowVersion& version, NTabletFlatExecutor::TTransactionContext& txc);
+    void RunSchemaTx(const NKikimrTxColumnShard::TSchemaTxBody& body, const NOlap::TSnapshot& version, NTabletFlatExecutor::TTransactionContext& txc);
+    void RunInit(const NKikimrTxColumnShard::TInitShard& body, const NOlap::TSnapshot& version, NTabletFlatExecutor::TTransactionContext& txc);
+    void RunEnsureTable(const NKikimrTxColumnShard::TCreateTable& body, const NOlap::TSnapshot& version, NTabletFlatExecutor::TTransactionContext& txc);
+    void RunAlterTable(const NKikimrTxColumnShard::TAlterTable& body, const NOlap::TSnapshot& version, NTabletFlatExecutor::TTransactionContext& txc);
+    void RunDropTable(const NKikimrTxColumnShard::TDropTable& body, const NOlap::TSnapshot& version, NTabletFlatExecutor::TTransactionContext& txc);
+    void RunAlterStore(const NKikimrTxColumnShard::TAlterStore& body, const NOlap::TSnapshot& version, NTabletFlatExecutor::TTransactionContext& txc);
 
     void StartIndexTask(std::vector<const NOlap::TInsertedData*>&& dataToIndex, const i64 bytesToIndex);
     void SetupIndexation();
@@ -493,7 +493,6 @@ private:
 
     static TDuration GetControllerPeriodicWakeupActivationPeriod();
     static TDuration GetControllerStatsReportInterval();
-    
 public:
     const std::shared_ptr<NOlap::IStoragesManager>& GetStoragesManager() const {
         return StoragesManager;
diff --git a/ydb/core/tx/columnshard/columnshard_schema.h b/ydb/core/tx/columnshard/columnshard_schema.h
index 1dc2ede706..c55cf2ed57 100644
--- a/ydb/core/tx/columnshard/columnshard_schema.h
+++ b/ydb/core/tx/columnshard/columnshard_schema.h
@@ -392,23 +392,23 @@ struct Schema : NIceDb::Schema {
 
     static void SaveSchemaPresetVersionInfo(
             NIceDb::TNiceDb& db,
-            ui64 id, const TRowVersion& version,
+            ui64 id, const NOlap::TSnapshot& version,
             const NKikimrTxColumnShard::TSchemaPresetVersionInfo& info)
     {
         TString serialized;
         Y_ABORT_UNLESS(info.SerializeToString(&serialized));
-        db.Table<SchemaPresetVersionInfo>().Key(id, version.Step, version.TxId).Update(
+        db.Table<SchemaPresetVersionInfo>().Key(id, version.GetPlanStep(), version.GetTxId()).Update(
             NIceDb::TUpdate<SchemaPresetVersionInfo::InfoProto>(serialized));
     }
 
-    static void SaveSchemaPresetDropVersion(NIceDb::TNiceDb& db, ui64 id, const TRowVersion& dropVersion) {
+    static void SaveSchemaPresetDropVersion(NIceDb::TNiceDb& db, ui64 id, const NOlap::TSnapshot& dropVersion) {
         db.Table<SchemaPresetInfo>().Key(id).Update(
-            NIceDb::TUpdate<SchemaPresetInfo::DropStep>(dropVersion.Step),
-            NIceDb::TUpdate<SchemaPresetInfo::DropTxId>(dropVersion.TxId));
+            NIceDb::TUpdate<SchemaPresetInfo::DropStep>(dropVersion.GetPlanStep()),
+            NIceDb::TUpdate<SchemaPresetInfo::DropTxId>(dropVersion.GetTxId()));
     }
 
-    static void EraseSchemaPresetVersionInfo(NIceDb::TNiceDb& db, ui64 id, const TRowVersion& version) {
-        db.Table<SchemaPresetVersionInfo>().Key(id, version.Step, version.TxId).Delete();
+    static void EraseSchemaPresetVersionInfo(NIceDb::TNiceDb& db, ui64 id, const NOlap::TSnapshot& version) {
+        db.Table<SchemaPresetVersionInfo>().Key(id, version.GetPlanStep(), version.GetTxId()).Delete();
     }
 
     static void EraseSchemaPresetInfo(NIceDb::TNiceDb& db, ui64 id) {
@@ -424,12 +424,12 @@ struct Schema : NIceDb::Schema {
 
     static void SaveTableVersionInfo(
             NIceDb::TNiceDb& db,
-            ui64 pathId, const TRowVersion& version,
+            ui64 pathId, const NOlap::TSnapshot& version,
             const NKikimrTxColumnShard::TTableVersionInfo& info)
     {
         TString serialized;
         Y_ABORT_UNLESS(info.SerializeToString(&serialized));
-        db.Table<TableVersionInfo>().Key(pathId, version.Step, version.TxId).Update(
+        db.Table<TableVersionInfo>().Key(pathId, version.GetPlanStep(), version.GetTxId()).Update(
             NIceDb::TUpdate<TableVersionInfo::InfoProto>(serialized));
     }
 
@@ -441,8 +441,8 @@ struct Schema : NIceDb::Schema {
             NIceDb::TUpdate<TableInfo::DropTxId>(dropTxId));
     }
 
-    static void EraseTableVersionInfo(NIceDb::TNiceDb& db, ui64 pathId, const TRowVersion& version) {
-        db.Table<TableVersionInfo>().Key(pathId, version.Step, version.TxId).Delete();
+    static void EraseTableVersionInfo(NIceDb::TNiceDb& db, ui64 pathId, const NOlap::TSnapshot& version) {
+        db.Table<TableVersionInfo>().Key(pathId, version.GetPlanStep(), version.GetTxId()).Delete();
     }
 
     static void EraseTableInfo(NIceDb::TNiceDb& db, ui64 pathId) {
diff --git a/ydb/core/tx/columnshard/tables_manager.cpp b/ydb/core/tx/columnshard/tables_manager.cpp
index d3bd5489d4..c100b8d348 100644
--- a/ydb/core/tx/columnshard/tables_manager.cpp
+++ b/ydb/core/tx/columnshard/tables_manager.cpp
@@ -95,13 +95,13 @@ bool TTablesManager::InitFromDB(NIceDb::TNiceDb& db) {
             return false;
         }
 
-        THashMap<ui64, TRowVersion> lastVersion;
+        THashMap<ui64, NOlap::TSnapshot> lastVersion;
         while (!rowset.EndOfSet()) {
             const ui64 pathId = rowset.GetValue<Schema::TableVersionInfo::PathId>();
             Y_ABORT_UNLESS(Tables.contains(pathId));
-            TRowVersion version(
+            NOlap::TSnapshot version(
                 rowset.GetValue<Schema::TableVersionInfo::SinceStep>(),
-                rowset.GetValue<Schema::TableVersionInfo::SinceTxId>());
+                    rowset.GetValue<Schema::TableVersionInfo::SinceTxId>());
 
             auto& table = Tables.at(pathId);
             TTableInfo::TTableVersionInfo versionInfo;
@@ -112,10 +112,11 @@ bool TTablesManager::InitFromDB(NIceDb::TNiceDb& db) {
             if (!table.IsDropped()) {
                 auto& ttlSettings = versionInfo.GetTtlSettings();
                 if (ttlSettings.HasEnabled()) {
-                    if (!lastVersion.contains(pathId) || lastVersion[pathId] < version) {
+                    auto vIt = lastVersion.find(pathId);
+                    if (vIt == lastVersion.end() || vIt->second < version) {
                         TTtl::TDescription description(ttlSettings.GetEnabled());
                         Ttl.SetPathTtl(pathId, std::move(description));
-                        lastVersion[pathId] = version;
+                        lastVersion.emplace(pathId, version);
                     }
                 }
             }
@@ -136,7 +137,7 @@ bool TTablesManager::InitFromDB(NIceDb::TNiceDb& db) {
             const ui32 id = rowset.GetValue<Schema::SchemaPresetVersionInfo::Id>();
             Y_ABORT_UNLESS(SchemaPresets.contains(id));
             auto& preset = SchemaPresets.at(id);
-            TRowVersion version(
+            NOlap::TSnapshot version(
                 rowset.GetValue<Schema::SchemaPresetVersionInfo::SinceStep>(),
                 rowset.GetValue<Schema::SchemaPresetVersionInfo::SinceTxId>());
 
@@ -208,7 +209,7 @@ ui64 TTablesManager::GetMemoryUsage() const {
     return memory;
 }
 
-void TTablesManager::DropTable(const ui64 pathId, const TRowVersion& version, NIceDb::TNiceDb& db) {
+void TTablesManager::DropTable(const ui64 pathId, const NOlap::TSnapshot& version, NIceDb::TNiceDb& db) {
     auto& table = Tables.at(pathId);
     table.SetDropVersion(version);
     PathsToDrop.insert(pathId);
@@ -216,10 +217,10 @@ void TTablesManager::DropTable(const ui64 pathId, const TRowVersion& version, NI
     if (PrimaryIndex) {
         PrimaryIndex->OnTieringModified(nullptr, Ttl);
     }
-    Schema::SaveTableDropVersion(db, pathId, version.Step, version.TxId);
+    Schema::SaveTableDropVersion(db, pathId, version.GetPlanStep(), version.GetTxId());
 }
 
-void TTablesManager::DropPreset(const ui32 presetId, const TRowVersion& version, NIceDb::TNiceDb& db) {
+void TTablesManager::DropPreset(const ui32 presetId, const NOlap::TSnapshot& version, NIceDb::TNiceDb& db) {
     auto& preset = SchemaPresets.at(presetId);
     Y_ABORT_UNLESS(preset.GetName() != "default", "Cannot drop the default preset");
     preset.SetDropVersion(version);
@@ -247,14 +248,14 @@ bool TTablesManager::RegisterSchemaPreset(const TSchemaPreset& schemaPreset, NIc
     return true;
 }
 
-void TTablesManager::AddSchemaVersion(const ui32 presetId, const TRowVersion& version, const NKikimrSchemeOp::TColumnTableSchema& schema, NIceDb::TNiceDb& db) {
+void TTablesManager::AddSchemaVersion(const ui32 presetId, const NOlap::TSnapshot& version, const NKikimrSchemeOp::TColumnTableSchema& schema, NIceDb::TNiceDb& db) {
     Y_ABORT_UNLESS(SchemaPresets.contains(presetId));
     auto preset = SchemaPresets.at(presetId);
 
     TSchemaPreset::TSchemaPresetVersionInfo versionInfo;
     versionInfo.SetId(presetId);
-    versionInfo.SetSinceStep(version.Step);
-    versionInfo.SetSinceTxId(version.TxId);
+    versionInfo.SetSinceStep(version.GetPlanStep());
+    versionInfo.SetSinceTxId(version.GetTxId());
     *versionInfo.MutableSchema() = schema;
 
     auto& schemaPreset = SchemaPresets.at(presetId);
@@ -268,7 +269,7 @@ void TTablesManager::AddSchemaVersion(const ui32 presetId, const TRowVersion& ve
     }
 }
 
-void TTablesManager::AddTableVersion(const ui64 pathId, const TRowVersion& version, const TTableInfo::TTableVersionInfo& versionInfo, NIceDb::TNiceDb& db) {
+void TTablesManager::AddTableVersion(const ui64 pathId, const NOlap::TSnapshot& version, const TTableInfo::TTableVersionInfo& versionInfo, NIceDb::TNiceDb& db) {
     auto& table = Tables.at(pathId);
 
     if (versionInfo.HasSchemaPresetId()) {
@@ -300,8 +301,7 @@ void TTablesManager::AddTableVersion(const ui64 pathId, const TRowVersion& versi
     table.AddVersion(version, versionInfo);
 }
 
-void TTablesManager::IndexSchemaVersion(const TRowVersion& version, const NKikimrSchemeOp::TColumnTableSchema& schema) {
-    NOlap::TSnapshot snapshot{version.Step, version.TxId};
+void TTablesManager::IndexSchemaVersion(const NOlap::TSnapshot& snapshot, const NKikimrSchemeOp::TColumnTableSchema& schema) {
     NOlap::TIndexInfo indexInfo = DeserializeIndexInfoFromProto(schema);
     indexInfo.SetAllKeys();
     const bool isFirstPrimaryIndexInitialization = !PrimaryIndex;
@@ -341,7 +341,7 @@ bool TTablesManager::TryFinalizeDropPath(NTabletFlatExecutor::TTransactionContex
     NIceDb::TNiceDb db(txc.DB);
     NColumnShard::Schema::EraseTableInfo(db, pathId);
     const auto& table = Tables.find(pathId);
-    Y_ABORT_UNLESS(table != Tables.end(), "No schema for path %lu", pathId); 
+    Y_ABORT_UNLESS(table != Tables.end(), "No schema for path %lu", pathId);
     for (auto&& tableVersion : table->second.GetVersions()) {
         NColumnShard::Schema::EraseTableVersionInfo(db, pathId, tableVersion.first);
     }
diff --git a/ydb/core/tx/columnshard/tables_manager.h b/ydb/core/tx/columnshard/tables_manager.h
index 33e6806a13..725bf197c2 100644
--- a/ydb/core/tx/columnshard/tables_manager.h
+++ b/ydb/core/tx/columnshard/tables_manager.h
@@ -16,8 +16,8 @@ namespace NKikimr::NColumnShard {
 template<class TSchemaProto>
 class TVersionedSchema {
 protected:
-    std::optional<TRowVersion> DropVersion;
-    TMap<TRowVersion, TSchemaProto> Versions;
+    std::optional<NOlap::TSnapshot> DropVersion;
+    TMap<NOlap::TSnapshot, TSchemaProto> Versions;
 
 public:
     bool IsDropped() const {
@@ -28,15 +28,15 @@ public:
         return Versions.empty();
     }
 
-    void SetDropVersion(const TRowVersion& version) {
+    void SetDropVersion(const NOlap::TSnapshot& version) {
         DropVersion = version;
     }
 
-    const TMap<TRowVersion, TSchemaProto>& GetVersions() const {
+    const TMap<NOlap::TSnapshot, TSchemaProto>& GetVersions() const {
         return Versions;
     }
 
-    const TSchemaProto& GetVersion(const TRowVersion& version) const {
+    const TSchemaProto& GetVersion(const NOlap::TSnapshot& version) const {
         const TSchemaProto* result = nullptr;
         for (auto ver : Versions) {
             if (ver.first > version) {
@@ -48,7 +48,7 @@ public:
         return *result;
     }
 
-    void AddVersion(const TRowVersion& version, const TSchemaProto& versionInfo) {
+    void AddVersion(const NOlap::TSnapshot& version, const TSchemaProto& versionInfo) {
         Versions[version] = versionInfo;
     }
 };
@@ -84,9 +84,8 @@ public:
         if (rowset.template HaveValue<Schema::SchemaPresetInfo::DropStep>() &&
             rowset.template HaveValue<Schema::SchemaPresetInfo::DropTxId>())
         {
-            DropVersion.emplace();
-            DropVersion->Step = rowset.template GetValue<Schema::SchemaPresetInfo::DropStep>();
-            DropVersion->TxId = rowset.template GetValue<Schema::SchemaPresetInfo::DropTxId>();
+            DropVersion.emplace(rowset.template GetValue<Schema::SchemaPresetInfo::DropStep>(),
+                rowset.template GetValue<Schema::SchemaPresetInfo::DropTxId>());
         }
         return true;
     }
@@ -123,9 +122,7 @@ public:
         PathId = rowset.template GetValue<Schema::TableInfo::PathId>();
         TieringUsage = rowset.template GetValue<Schema::TableInfo::TieringUsage>();
         if (rowset.template HaveValue<Schema::TableInfo::DropStep>() && rowset.template HaveValue<Schema::TableInfo::DropTxId>()) {
-            DropVersion.emplace();
-            DropVersion->Step = rowset.template GetValue<Schema::TableInfo::DropStep>();
-            DropVersion->TxId = rowset.template GetValue<Schema::TableInfo::DropTxId>();
+            DropVersion.emplace(rowset.template GetValue<Schema::TableInfo::DropStep>(), rowset.template GetValue<Schema::TableInfo::DropTxId>());
         }
         return true;
     }
@@ -202,17 +199,17 @@ public:
     bool IsReadyForWrite(const ui64 pathId) const;
     bool HasPreset(const ui32 presetId) const;
 
-    void DropTable(const ui64 pathId, const TRowVersion& version, NIceDb::TNiceDb& db);
-    void DropPreset(const ui32 presetId, const TRowVersion& version, NIceDb::TNiceDb& db);
+    void DropTable(const ui64 pathId, const NOlap::TSnapshot& version, NIceDb::TNiceDb& db);
+    void DropPreset(const ui32 presetId, const NOlap::TSnapshot& version, NIceDb::TNiceDb& db);
 
     void RegisterTable(TTableInfo&& table, NIceDb::TNiceDb& db);
     bool RegisterSchemaPreset(const TSchemaPreset& schemaPreset, NIceDb::TNiceDb& db);
 
-    void AddSchemaVersion(const ui32 presetId, const TRowVersion& version, const NKikimrSchemeOp::TColumnTableSchema& schema, NIceDb::TNiceDb& db);
-    void AddTableVersion(const ui64 pathId, const TRowVersion& version, const TTableInfo::TTableVersionInfo& versionInfo, NIceDb::TNiceDb& db);
+    void AddSchemaVersion(const ui32 presetId, const NOlap::TSnapshot& version, const NKikimrSchemeOp::TColumnTableSchema& schema, NIceDb::TNiceDb& db);
+    void AddTableVersion(const ui64 pathId, const NOlap::TSnapshot& version, const TTableInfo::TTableVersionInfo& versionInfo, NIceDb::TNiceDb& db);
     bool FillMonitoringReport(NTabletFlatExecutor::TTransactionContext& txc, NJson::TJsonValue& json);
 private:
-    void IndexSchemaVersion(const TRowVersion& version, const NKikimrSchemeOp::TColumnTableSchema& schema);
+    void IndexSchemaVersion(const NOlap::TSnapshot& version, const NKikimrSchemeOp::TColumnTableSchema& schema);
     static NOlap::TIndexInfo DeserializeIndexInfoFromProto(const NKikimrSchemeOp::TColumnTableSchema& schema);
 };