fix compaction memory prediction for special case (#11565)

Author: ivanmorozov333

ydb/core/tx/columnshard/engines/changes/general_compaction.cpp

@@ -238,7 +238,8 @@ std::shared_ptr<TGeneralCompactColumnEngineChanges::IMemoryPredictor> TGeneralCo
 
 ui64 TGeneralCompactColumnEngineChanges::TMemoryPredictorChunkedPolicy::AddPortion(const TPortionInfo::TConstPtr& portionInfo) {
     SumMemoryFix += portionInfo->GetRecordsCount() * (2 * sizeof(ui64) + sizeof(ui32) + sizeof(ui16)) + portionInfo->GetTotalBlobBytes();
-    return SumMemoryFix + ((ui64)500 << 20);
+    SumMemoryRaw += portionInfo->GetTotalRawBytes();
+    return SumMemoryFix + std::min<ui64>(SumMemoryRaw, ((ui64)500 << 20));
 }
 
 }   // namespace NKikimr::NOlap::NCompaction

ydb/core/tx/columnshard/engines/changes/general_compaction.h

@@ -50,6 +50,7 @@ class TGeneralCompactColumnEngineChanges: public TCompactColumnEngineChanges {
     class TMemoryPredictorChunkedPolicy: public IMemoryPredictor {
     private:
         ui64 SumMemoryFix = 0;
+        ui64 SumMemoryRaw = 0;
     public:
         virtual ui64 AddPortion(const TPortionInfo::TConstPtr& portionInfo) override;
     };