diff --git a/ydb/core/tx/columnshard/engines/changes/with_appended.cpp b/ydb/core/tx/columnshard/engines/changes/with_appended.cpp
index e954c6eeb9fd..59781a82bf5a 100644
--- a/ydb/core/tx/columnshard/engines/changes/with_appended.cpp
+++ b/ydb/core/tx/columnshard/engines/changes/with_appended.cpp
@@ -77,7 +77,7 @@ void TChangesWithAppend::DoWriteIndexOnComplete(NColumnShard::TColumnShard* self
                     break;
             }
         }
-        AFL_WARN(NKikimrServices::TX_COLUMNSHARD)("portions", sb)("task_id", GetTaskIdentifier());
+        AFL_DEBUG(NKikimrServices::TX_COLUMNSHARD)("portions", sb)("task_id", GetTaskIdentifier());
         self->Counters.GetTabletCounters()->IncCounter(NColumnShard::COUNTER_PORTIONS_DEACTIVATED, PortionsToRemove.size());
 
         for (auto& [_, portionInfo] : PortionsToRemove) {
diff --git a/ydb/core/tx/columnshard/engines/reader/common/result.h b/ydb/core/tx/columnshard/engines/reader/common/result.h
index 6173d3147e87..dce9aca55685 100644
--- a/ydb/core/tx/columnshard/engines/reader/common/result.h
+++ b/ydb/core/tx/columnshard/engines/reader/common/result.h
@@ -12,7 +12,7 @@ namespace NKikimr::NOlap::NReader {
 // Represents a batch of rows produced by ASC or DESC scan with applied filters and partial aggregation
 class TPartialReadResult: public TNonCopyable {
 private:
-    YDB_READONLY_DEF(std::shared_ptr<NGroupedMemoryManager::TAllocationGuard>, ResourcesGuard);
+    YDB_READONLY_DEF(std::vector<std::shared_ptr<NGroupedMemoryManager::TAllocationGuard>>, ResourceGuards);
     YDB_READONLY_DEF(std::shared_ptr<NGroupedMemoryManager::TGroupGuard>, GroupGuard);
     NArrow::TShardedRecordBatch ResultBatch;
 
@@ -54,11 +54,11 @@ class TPartialReadResult: public TNonCopyable {
         return ScanCursor;
     }
 
-    explicit TPartialReadResult(std::shared_ptr<NGroupedMemoryManager::TAllocationGuard>&& resourcesGuard,
-        std::shared_ptr<NGroupedMemoryManager::TGroupGuard>&& gGuard, const NArrow::TShardedRecordBatch& batch,
+    explicit TPartialReadResult(const std::vector<std::shared_ptr<NGroupedMemoryManager::TAllocationGuard>>& resourceGuards,
+        const std::shared_ptr<NGroupedMemoryManager::TGroupGuard>& gGuard, const NArrow::TShardedRecordBatch& batch,
         const std::shared_ptr<IScanCursor>& scanCursor, const std::optional<ui32> notFinishedIntervalIdx)
-        : ResourcesGuard(std::move(resourcesGuard))
-        , GroupGuard(std::move(gGuard))
+        : ResourceGuards(resourceGuards)
+        , GroupGuard(gGuard)
         , ResultBatch(batch)
         , ScanCursor(scanCursor)
         , NotFinishedIntervalIdx(notFinishedIntervalIdx) {
@@ -68,7 +68,7 @@ class TPartialReadResult: public TNonCopyable {
 
     explicit TPartialReadResult(const NArrow::TShardedRecordBatch& batch, const std::shared_ptr<IScanCursor>& scanCursor,
         const std::optional<ui32> notFinishedIntervalIdx)
-        : TPartialReadResult(nullptr, nullptr, batch, scanCursor, notFinishedIntervalIdx) {
+        : TPartialReadResult({}, nullptr, batch, scanCursor, notFinishedIntervalIdx) {
     }
 };
 
diff --git a/ydb/core/tx/columnshard/engines/reader/plain_reader/iterator/scanner.cpp b/ydb/core/tx/columnshard/engines/reader/plain_reader/iterator/scanner.cpp
index 6298efcdd13d..2ff33e594783 100644
--- a/ydb/core/tx/columnshard/engines/reader/plain_reader/iterator/scanner.cpp
+++ b/ydb/core/tx/columnshard/engines/reader/plain_reader/iterator/scanner.cpp
@@ -27,7 +27,8 @@ void TScanHead::OnIntervalResult(std::shared_ptr<NGroupedMemoryManager::TAllocat
         } else {
             gGuard = itInterval->second->GetGroupGuard();
         }
-        AFL_VERIFY(ReadyIntervals.emplace(intervalIdx, std::make_shared<TPartialReadResult>(std::move(allocationGuard), std::move(gGuard), *newBatch, 
+        std::vector<std::shared_ptr<NGroupedMemoryManager::TAllocationGuard>> guards = { std::move(allocationGuard) };
+        AFL_VERIFY(ReadyIntervals.emplace(intervalIdx, std::make_shared<TPartialReadResult>(guards, std::move(gGuard), *newBatch,
             std::make_shared<TPlainScanCursor>(lastPK), callbackIdxSubscriver)).second);
     } else {
         AFL_VERIFY(ReadyIntervals.emplace(intervalIdx, nullptr).second);
diff --git a/ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/context.cpp b/ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/context.cpp
index caa7f0330506..1ca0b8cae26a 100644
--- a/ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/context.cpp
+++ b/ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/context.cpp
@@ -96,27 +96,27 @@ class TColumnsAccumulator {
         const bool sequential) {
         auto actualColumns = columns - AssemblerReadyColumns;
         AssemblerReadyColumns = AssemblerReadyColumns + columns;
-        if (!actualColumns.IsEmpty()) {
-            auto actualSet = std::make_shared<TColumnsSet>(actualColumns.GetColumnIds(), FullSchema);
-            if (sequential) {
-                const auto notSequentialColumnIds = GuaranteeNotOptional->Intersect(*actualSet);
-                if (notSequentialColumnIds.size()) {
-                    script.Allocation(notSequentialColumnIds, stage, EMemType::Raw);
-                    std::shared_ptr<TColumnsSet> cross = actualSet->BuildSamePtr(notSequentialColumnIds);
-                    script.AddStep<TAssemblerStep>(cross, purposeId);
-                    *actualSet = *actualSet - *cross;
-                }
-                if (!actualSet->IsEmpty()) {
-                    script.Allocation(notSequentialColumnIds, stage, EMemType::RawSequential);
-                    script.AddStep<TOptionalAssemblerStep>(actualSet, purposeId);
-                }
-            } else {
-                script.Allocation(actualColumns.GetColumnIds(), stage, EMemType::Raw);
-                script.AddStep<TAssemblerStep>(actualSet, purposeId);
+        if (actualColumns.IsEmpty()) {
+            return false;
+        }
+        auto actualSet = std::make_shared<TColumnsSet>(actualColumns.GetColumnIds(), FullSchema);
+        if (sequential) {
+            const auto notSequentialColumnIds = GuaranteeNotOptional->Intersect(*actualSet);
+            if (notSequentialColumnIds.size()) {
+                script.Allocation(notSequentialColumnIds, stage, EMemType::Raw);
+                std::shared_ptr<TColumnsSet> cross = actualSet->BuildSamePtr(notSequentialColumnIds);
+                script.AddStep<TAssemblerStep>(cross, purposeId);
+                *actualSet = *actualSet - *cross;
             }
-            return true;
+            if (!actualSet->IsEmpty()) {
+                script.Allocation(notSequentialColumnIds, stage, EMemType::RawSequential);
+                script.AddStep<TOptionalAssemblerStep>(actualSet, purposeId);
+            }
+        } else {
+            script.Allocation(actualColumns.GetColumnIds(), stage, EMemType::Raw);
+            script.AddStep<TAssemblerStep>(actualSet, purposeId);
         }
-        return false;
+        return true;
     }
 };
 
diff --git a/ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/scanner.cpp b/ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/scanner.cpp
index 00a0ae70a15e..8a36491860b2 100644
--- a/ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/scanner.cpp
+++ b/ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/scanner.cpp
@@ -16,9 +16,13 @@ void TScanHead::OnSourceReady(const std::shared_ptr<IDataSource>& source, std::s
     while (FetchingSources.size()) {
         auto frontSource = *FetchingSources.begin();
         if (!frontSource->HasStageResult()) {
+            AFL_DEBUG(NKikimrServices::TX_COLUMNSHARD)("event", "skip_no_result")("source_id", frontSource->GetSourceId())(
+                "source_idx", frontSource->GetSourceIdx());
             break;
         }
         if (!frontSource->GetStageResult().HasResultChunk()) {
+            AFL_DEBUG(NKikimrServices::TX_COLUMNSHARD)("event", "skip_no_result_chunk")("source_id", frontSource->GetSourceId())(
+                "source_idx", frontSource->GetSourceIdx());
             break;
         }
         auto table = frontSource->MutableStageResult().ExtractResultChunk();
@@ -28,24 +32,32 @@ void TScanHead::OnSourceReady(const std::shared_ptr<IDataSource>& source, std::s
             sourceIdxToContinue = frontSource->GetSourceIdx();
         }
         if (table && table->num_rows()) {
+            AFL_DEBUG(NKikimrServices::TX_COLUMNSHARD)("event", "has_result")("source_id", frontSource->GetSourceId())(
+                "source_idx", frontSource->GetSourceIdx())("table", table->num_rows());
             auto cursor =
                 std::make_shared<TSimpleScanCursor>(frontSource->GetStartPKRecordBatch(), frontSource->GetSourceId(), startIndex + recordsCount);
-            reader.OnIntervalResult(std::make_shared<TPartialReadResult>(nullptr, nullptr, table, cursor, sourceIdxToContinue));
+            reader.OnIntervalResult(
+                std::make_shared<TPartialReadResult>(frontSource->GetResourceGuards(), frontSource->GetGroupGuard(), table, cursor, sourceIdxToContinue));
         } else if (sourceIdxToContinue) {
+            AFL_DEBUG(NKikimrServices::TX_COLUMNSHARD)("event", "continue_source")("source_id", frontSource->GetSourceId())(
+                "source_idx", frontSource->GetSourceIdx());
             ContinueSource(*sourceIdxToContinue);
             break;
         }
         if (!isFinished) {
             break;
         }
+        AFL_DEBUG(NKikimrServices::TX_COLUMNSHARD)("event", "source_finished")("source_id", frontSource->GetSourceId())(
+            "source_idx", frontSource->GetSourceIdx());
         AFL_VERIFY(FetchingSourcesByIdx.erase(frontSource->GetSourceIdx()));
         if (Context->GetCommonContext()->GetReadMetadata()->Limit) {
-            FinishedSources.emplace(*FetchingSources.begin());
+            frontSource->ClearResult();
+            FinishedSources.emplace(frontSource);
         }
         FetchingSources.erase(FetchingSources.begin());
         while (FetchingSources.size() && FinishedSources.size()) {
-            auto finishedSource = *FinishedSources.begin();
             auto fetchingSource = *FetchingSources.begin();
+            auto finishedSource = *FinishedSources.begin();
             if (finishedSource->GetFinish() < fetchingSource->GetStart()) {
                 FetchedCount += finishedSource->GetRecordsCount();
             }
diff --git a/ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/source.cpp b/ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/source.cpp
index 9c578661f064..9cd55c438ed7 100644
--- a/ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/source.cpp
+++ b/ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/source.cpp
@@ -25,6 +25,8 @@ void IDataSource::StartProcessing(const std::shared_ptr<IDataSource>& sourcePtr)
     AFL_VERIFY(FetchingPlan);
     AFL_VERIFY(!Context->IsAborted());
     ProcessingStarted = true;
+    SourceGroupGuard = NGroupedMemoryManager::TScanMemoryLimiterOperator::BuildGroupGuard(
+        GetContext()->GetProcessMemoryControlId(), GetContext()->GetCommonContext()->GetScanId());
     AFL_DEBUG(NKikimrServices::TX_COLUMNSHARD_SCAN)("InitFetchingPlan", FetchingPlan->DebugString())("source_idx", SourceIdx);
     NActors::TLogContextGuard logGuard(NActors::TLogContextBuilder::Build()("source", SourceIdx)("method", "InitFetchingPlan"));
     TFetchingScriptCursor cursor(FetchingPlan, 0);
@@ -237,9 +239,7 @@ TPortionDataSource::TPortionDataSource(
           portion->RecordSnapshotMin(TSnapshot::Zero()), portion->RecordSnapshotMax(TSnapshot::Zero()), portion->GetRecordsCount(),
           portion->GetShardingVersionOptional(), portion->GetMeta().GetDeletionsCount())
     , Portion(portion)
-    , Schema(GetContext()->GetReadMetadata()->GetLoadSchemaVerified(*portion))
-    , SourceGroupGuard(NGroupedMemoryManager::TScanMemoryLimiterOperator::BuildGroupGuard(
-          GetContext()->GetProcessMemoryControlId(), GetContext()->GetCommonContext()->GetScanId())) {
+    , Schema(GetContext()->GetReadMetadata()->GetLoadSchemaVerified(*portion)) {
 }
 
 }   // namespace NKikimr::NOlap::NReader::NSimple
diff --git a/ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/source.h b/ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/source.h
index 91c4533cb773..ea6d499321ae 100644
--- a/ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/source.h
+++ b/ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/source.h
@@ -60,7 +60,7 @@ class IDataSource: public ICursorEntity {
     YDB_READONLY(bool, HasDeletions, false);
     virtual NJson::TJsonValue DoDebugJson() const = 0;
     std::shared_ptr<TFetchingScript> FetchingPlan;
-    std::vector<std::shared_ptr<NGroupedMemoryManager::TAllocationGuard>> ResourceGuards;
+    YDB_READONLY_DEF(std::vector<std::shared_ptr<NGroupedMemoryManager::TAllocationGuard>>, ResourceGuards);
     YDB_READONLY(TPKRangeFilter::EUsageClass, UsageClass, TPKRangeFilter::EUsageClass::PartialUsage);
     bool ProcessingStarted = false;
     bool IsStartedByCursor = false;
@@ -74,7 +74,7 @@ class IDataSource: public ICursorEntity {
     }
 
     std::optional<TFetchingScriptCursor> ScriptCursor;
-
+    std::shared_ptr<NGroupedMemoryManager::TGroupGuard> SourceGroupGuard;
 protected:
     std::optional<bool> IsSourceInMemoryFlag;
 
@@ -95,11 +95,27 @@ class IDataSource: public ICursorEntity {
     virtual bool DoStartFetchingAccessor(const std::shared_ptr<IDataSource>& sourcePtr, const TFetchingScriptCursor& step) = 0;
 
 public:
-    virtual ui64 GetMemoryGroupId() const = 0;
     bool GetIsStartedByCursor() const {
         return IsStartedByCursor;
     }
 
+    const std::shared_ptr<NGroupedMemoryManager::TGroupGuard>& GetGroupGuard() const {
+        AFL_VERIFY(SourceGroupGuard);
+        return SourceGroupGuard;
+    }
+
+    ui64 GetMemoryGroupId() const {
+        AFL_VERIFY(SourceGroupGuard);
+        return SourceGroupGuard->GetGroupId();
+    }
+
+    virtual void ClearResult() {
+        StageData.reset();
+        StageResult.reset();
+        ResourceGuards.clear();
+        SourceGroupGuard = nullptr;
+    }
+
     void SetIsStartedByCursor() {
         IsStartedByCursor = true;
     }
@@ -323,7 +339,6 @@ class TPortionDataSource: public IDataSource {
     using TBase = IDataSource;
     const TPortionInfo::TConstPtr Portion;
     std::shared_ptr<ISnapshotSchema> Schema;
-    const std::shared_ptr<NGroupedMemoryManager::TGroupGuard> SourceGroupGuard;
 
     void NeedFetchColumns(const std::set<ui32>& columnIds, TBlobsAction& blobsAction,
         THashMap<TChunkAddress, TPortionDataAccessor::TAssembleBlobInfo>& nullBlocks, const std::shared_ptr<NArrow::TColumnFilter>& filter);
@@ -365,10 +380,6 @@ class TPortionDataSource: public IDataSource {
     virtual bool DoStartFetchingAccessor(const std::shared_ptr<IDataSource>& sourcePtr, const TFetchingScriptCursor& step) override;
 
 public:
-    virtual ui64 GetMemoryGroupId() const override {
-        return SourceGroupGuard->GetGroupId();
-    }
-
     virtual ui64 PredictAccessorsSize() const override {
         return Portion->GetApproxChunksCount(GetContext()->GetCommonContext()->GetReadMetadata()->GetResultSchema()->GetColumnsCount()) * sizeof(TColumnRecord);
     }
diff --git a/ydb/core/tx/columnshard/engines/storage/granule/storage.cpp b/ydb/core/tx/columnshard/engines/storage/granule/storage.cpp
index a8c9a092bc32..b8953946ba83 100644
--- a/ydb/core/tx/columnshard/engines/storage/granule/storage.cpp
+++ b/ydb/core/tx/columnshard/engines/storage/granule/storage.cpp
@@ -63,7 +63,7 @@ std::optional<NStorageOptimizer::TOptimizationPriority> TGranulesStorage::GetCom
             maxPriorityGranule = granulesSorted.front().GetGranule();
             break;
         }
-        AFL_WARN(NKikimrServices::TX_COLUMNSHARD)("event", "granule_locked")("path_id", granulesSorted.front().GetGranule()->GetPathId());
+        AFL_DEBUG(NKikimrServices::TX_COLUMNSHARD)("event", "granule_locked")("path_id", granulesSorted.front().GetGranule()->GetPathId());
         std::pop_heap(granulesSorted.begin(), granulesSorted.end());
         granulesSorted.pop_back();
     }
diff --git a/ydb/core/tx/columnshard/engines/storage/optimizer/lcbuckets/planner/optimizer.cpp b/ydb/core/tx/columnshard/engines/storage/optimizer/lcbuckets/planner/optimizer.cpp
index a5ffa1c95df7..6ed2c11da611 100644
--- a/ydb/core/tx/columnshard/engines/storage/optimizer/lcbuckets/planner/optimizer.cpp
+++ b/ydb/core/tx/columnshard/engines/storage/optimizer/lcbuckets/planner/optimizer.cpp
@@ -47,7 +47,7 @@ std::shared_ptr<TColumnEngineChanges> TOptimizerPlanner::DoGetOptimizationTask(
         result->SetPortionExpectedSize(levelPortions->GetExpectedPortionSize());
     }
     auto positions = data.GetCheckPositions(PrimaryKeysSchema, level->GetLevelId() > 1);
-    AFL_WARN(NKikimrServices::TX_COLUMNSHARD)("task_id", result->GetTaskIdentifier())("positions", positions.DebugString())(
+    AFL_DEBUG(NKikimrServices::TX_COLUMNSHARD)("task_id", result->GetTaskIdentifier())("positions", positions.DebugString())(
         "level", level->GetLevelId())("target", data.GetTargetCompactionLevel())("data", data.DebugString());
     result->SetCheckPoints(std::move(positions));
     for (auto&& i : result->GetSwitchedPortions()) {