fix (#29485)

Author: XJIE6

ydb/core/formats/arrow/program/abstract.h

@@ -48,14 +48,12 @@ class TFetchingCalculationPolicy: public IMemoryCalculationPolicy {
         return EStage::Fetching;
     }
     virtual ui64 GetReserveMemorySize(
-        const ui64 blobsSize, const ui64 rawSize, const std::optional<ui32> /*limit*/, const ui32 /*recordsCount*/) const override {
-        return std::max<ui64>(blobsSize, rawSize);
-        // FIXME after futher memory usage investagiation
-        // if (limit) {
-        //     return std::max<ui64>(blobsSize, rawSize * (1.0 * *limit) / recordsCount);
-        // } else {
-        //     return std::max<ui64>(blobsSize, rawSize);
-        // }
+        const ui64 blobsSize, const ui64 rawSize, const std::optional<ui32> limit, const ui32 recordsCount) const override {
+        if (limit && *limit < recordsCount) {
+            return std::max<ui64>(blobsSize, rawSize * (1.0 * *limit) / recordsCount);
+        } else {
+            return std::max<ui64>(blobsSize, rawSize);
+        }
     }
 };