fixes

Author: ivanmorozov333

ydb/core/formats/arrow/accessor/composite/accessor.cpp

@@ -55,4 +55,16 @@ NArrow::NAccessor::IChunkedArray::TCurrentArrayAddress TCompositeChunkedArray::D
     return *result;
 }
 
+std::shared_ptr<arrow::ChunkedArray> TCompositeChunkedArray::DoGetChunkedArray() const {
+    std::vector<std::shared_ptr<arrow::Array>> chunks;
+    for (auto&& i : Chunks) {
+        auto arr = i->GetChunkedArray();
+        AFL_VERIFY(arr->num_chunks());
+        for (auto&& chunk : arr->chunks()) {
+            chunks.emplace_back(chunk);
+        }
+    }
+    return std::make_shared<arrow::ChunkedArray>(chunks);
+}
+
 }   // namespace NKikimr::NArrow::NAccessor

ydb/core/formats/arrow/accessor/composite/accessor.h

@@ -33,10 +33,7 @@ class TCompositeChunkedArray: public NArrow::NAccessor::IChunkedArray {
         return nullptr;
     }
     virtual TCurrentChunkAddress DoGetChunk(const std::optional<TCurrentChunkAddress>& chunkCurrent, const ui64 position) const override;
-    virtual std::shared_ptr<arrow::ChunkedArray> DoGetChunkedArray() const override {
-        AFL_VERIFY(false);
-        return nullptr;
-    }
+    virtual std::shared_ptr<arrow::ChunkedArray> DoGetChunkedArray() const override;
 
     TCompositeChunkedArray(std::vector<std::shared_ptr<NArrow::NAccessor::IChunkedArray>>&& chunks, const ui32 recordsCount,
         const std::shared_ptr<arrow::DataType>& type)