Support Parquet filetype on COPY TO

src/binder/bind/bind_copy.cpp

@@ -21,18 +21,22 @@ std::unique_ptr<BoundStatement> Binder::bindCopyToClause(const Statement& statem
     auto boundFilePath = copyToStatement.getFilePath();
     auto fileType = bindFileType(boundFilePath);
     std::vector<std::string> columnNames;
+    std::vector<LogicalType> columnTypes;
     auto query = bindQuery(*copyToStatement.getRegularQuery());
     auto columns = query->getStatementResult()->getColumns();
     for (auto& column : columns) {
         auto columnName = column->hasAlias() ? column->getAlias() : column->toString();
         columnNames.push_back(columnName);
+        columnTypes.push_back(column->getDataType());
     }
-    if (fileType != CopyDescription::FileType::CSV) {
-        throw BinderException("COPY TO currently only supports csv files.");
+    if (fileType != CopyDescription::FileType::CSV &&
+        fileType != CopyDescription::FileType::PARQUET) {
+        throw BinderException(ExceptionMessage::validateCopyToCSVParquetExtensionsException());
     }
     auto copyDescription = std::make_unique<CopyDescription>(
         fileType, std::vector<std::string>{boundFilePath}, nullptr /* parsing option */);
     copyDescription->columnNames = columnNames;
+    copyDescription->columnTypes = columnTypes;
     return std::make_unique<BoundCopyTo>(std::move(copyDescription), std::move(query));
 }
 

src/common/types/types.cpp

@@ -621,6 +621,19 @@ bool LogicalTypeUtils::isNumerical(const LogicalType& dataType) {
     }
 }
 
+bool LogicalTypeUtils::isNested(const LogicalType& dataType) {
+    switch (dataType.typeID) {
+    case LogicalTypeID::STRUCT:
+    case LogicalTypeID::VAR_LIST:
+    case LogicalTypeID::FIXED_LIST:
+    case LogicalTypeID::UNION:
+    case LogicalTypeID::MAP:
+        return true;
+    default:
+        return false;
+    }
+}
+
 std::vector<LogicalType> LogicalTypeUtils::getAllValidComparableLogicalTypes() {
     return std::vector<LogicalType>{LogicalType{LogicalTypeID::BOOL},
         LogicalType{LogicalTypeID::INT64}, LogicalType{LogicalTypeID::INT32},

src/include/common/copier_config/copier_config.h

@@ -6,6 +6,7 @@
 #include <vector>
 
 #include "common/constants.h"
+#include "common/types/types.h"
 
 namespace kuzu {
 namespace common {
@@ -40,14 +41,16 @@ struct CopyDescription {
     FileType fileType;
     std::vector<std::string> filePaths;
     std::vector<std::string> columnNames;
+    std::vector<LogicalType> columnTypes;
     std::unique_ptr<CSVReaderConfig> csvReaderConfig;
 
     CopyDescription(FileType fileType, const std::vector<std::string>& filePaths,
         std::unique_ptr<CSVReaderConfig> csvReaderConfig)
         : fileType{fileType}, filePaths{filePaths}, csvReaderConfig{std::move(csvReaderConfig)} {}
 
     CopyDescription(const CopyDescription& other)
-        : fileType{other.fileType}, filePaths{other.filePaths}, columnNames{other.columnNames} {
+        : fileType{other.fileType}, filePaths{other.filePaths}, columnNames{other.columnNames},
+          columnTypes{other.columnTypes} {
         if (other.csvReaderConfig != nullptr) {
             this->csvReaderConfig = std::make_unique<CSVReaderConfig>(*other.csvReaderConfig);
         }
@@ -67,6 +70,8 @@ struct CopyDescription {
         {".npy", FileType::NPY}, {".ttl", FileType::TURTLE}};
 
     static FileType getFileTypeFromExtension(const std::string& extension);
+
+    static std::string getFileTypeName(FileType fileType);
 };
 
 } // namespace common

src/include/common/exception/message.h

@@ -24,6 +24,9 @@ struct ExceptionMessage {
     static inline std::string validateCopyCSVParquetByColumnException() {
         return "Please use COPY FROM statement for copying csv and parquet files.";
     }
+    static inline std::string validateCopyToCSVParquetExtensionsException() {
+        return "COPY TO currently only supports csv and parquet files.";
+    }
     static std::string validateCopyNpyNotForRelTablesException(const std::string& tableName);
 };
 

src/include/common/types/types.h

@@ -423,6 +423,7 @@ class LogicalTypeUtils {
     KUZU_API static LogicalType dataTypeFromString(const std::string& dataTypeString);
     static uint32_t getRowLayoutSize(const LogicalType& logicalType);
     static bool isNumerical(const LogicalType& dataType);
+    static bool isNested(const LogicalType& dataType);
     static std::vector<LogicalType> getAllValidComparableLogicalTypes();
     static std::vector<LogicalTypeID> getNumericalLogicalTypeIDs();
     static std::vector<LogicalType> getAllValidLogicTypes();

src/include/processor/operator/persistent/copy_to.h

@@ -3,40 +3,57 @@
 #include "common/copier_config/copier_config.h"
 #include "common/task_system/task_scheduler.h"
 #include "processor/operator/persistent/csv_file_writer.h"
+#include "processor/operator/persistent/file_writer.h"
+#include "processor/operator/persistent/parquet_file_writer.h"
 #include "processor/operator/physical_operator.h"
+#include "processor/operator/sink.h"
 #include "processor/result/result_set.h"
 
 namespace kuzu {
 namespace processor {
 
-class WriteCSVFileSharedState {
+class CopyToSharedState {
 public:
-    WriteCSVFileSharedState() {
-        csvFileWriter = std::make_unique<kuzu::processor::CSVFileWriter>();
-    };
-    std::unique_ptr<kuzu::processor::CSVFileWriter> csvFileWriter;
+    CopyToSharedState(common::CopyDescription::FileType fileType, std::string& filePath,
+        std::vector<std::string>& columnNames, std::vector<common::LogicalType>& columnTypes) {
+        if (fileType == common::CopyDescription::FileType::CSV) {
+            fileWriter = std::make_unique<kuzu::processor::CSVFileWriter>(
+                filePath, columnNames, columnTypes);
+        } else if (fileType == common::CopyDescription::FileType::PARQUET) {
+            fileWriter = std::make_unique<kuzu::processor::ParquetFileWriter>(
+                filePath, columnNames, columnTypes);
+        } else {
+            throw common::NotImplementedException("CopyToSharedState::CopyToSharedState");
+        }
+    }
+    inline std::unique_ptr<FileWriter>& getWriter() { return fileWriter; }
+
+private:
+    std::unique_ptr<FileWriter> fileWriter;
 };
 
-class CopyTo : public PhysicalOperator {
+class CopyTo : public Sink {
 public:
-    CopyTo(std::shared_ptr<WriteCSVFileSharedState> sharedState,
-        std::vector<DataPos> vectorsToCopyPos, const common::CopyDescription& copyDescription,
-        uint32_t id, const std::string& paramsString, std::unique_ptr<PhysicalOperator> child)
-        : PhysicalOperator{PhysicalOperatorType::COPY_TO, std::move(child), id, paramsString},
+    CopyTo(std::unique_ptr<ResultSetDescriptor> resultSetDescriptor,
+        std::shared_ptr<CopyToSharedState> sharedState, std::vector<DataPos> vectorsToCopyPos,
+        const common::CopyDescription& copyDescription, uint32_t id,
+        const std::string& paramsString, std::unique_ptr<PhysicalOperator> child)
+        : Sink{std::move(resultSetDescriptor), PhysicalOperatorType::COPY_TO, std::move(child), id,
+              paramsString},
           sharedState{std::move(sharedState)}, vectorsToCopyPos{std::move(vectorsToCopyPos)},
           copyDescription{copyDescription} {}
 
     inline bool canParallel() const final { return false; }
 
-    bool getNextTuplesInternal(ExecutionContext* context) override;
+    void executeInternal(ExecutionContext* context) final;
 
-    common::CopyDescription& getCopyDescription() { return copyDescription; }
+    void finalize(ExecutionContext* context) final;
 
-    void initLocalStateInternal(ResultSet* resultSet, ExecutionContext* context) override;
+    common::CopyDescription& getCopyDescription() { return copyDescription; }
 
-    std::unique_ptr<PhysicalOperator> clone() override {
-        return make_unique<CopyTo>(
-            sharedState, vectorsToCopyPos, copyDescription, id, paramsString, children[0]->clone());
+    std::unique_ptr<PhysicalOperator> clone() final {
+        return make_unique<CopyTo>(resultSetDescriptor->copy(), sharedState, vectorsToCopyPos,
+            copyDescription, id, paramsString, children[0]->clone());
     }
 
 protected:
@@ -45,9 +62,10 @@
 
 private:
     void initGlobalStateInternal(ExecutionContext* context) override;
+    void initLocalStateInternal(ResultSet* resultSet, ExecutionContext* context) override;
     common::CopyDescription copyDescription;
     std::vector<common::ValueVector*> outputVectors;
-    std::shared_ptr<WriteCSVFileSharedState> sharedState;
+    std::shared_ptr<CopyToSharedState> sharedState;
 };
 
 } // namespace processor

src/include/processor/operator/persistent/csv_file_writer.h

@@ -1,29 +1,30 @@
 #pragma once
 
-#include "common/copier_config/copier_config.h"
-#include "common/file_utils.h"
+#include "processor/operator/persistent/file_writer.h"
 #include "processor/result/result_set.h"
 
 namespace kuzu {
 namespace processor {
 
-class CSVFileWriter {
+class CSVFileWriter : public FileWriter {
 public:
-    CSVFileWriter(){};
-    void open(const std::string& filePath);
-    void writeHeader(const std::vector<std::string>& columnNames);
-    void writeValues(std::vector<common::ValueVector*>& outputVectors);
+    using FileWriter::FileWriter;
+    void openFile() final;
+    void init() final;
+    inline void closeFile() final { flush(); }
+    void writeValues(std::vector<common::ValueVector*>& outputVectors) final;
 
 private:
+    void writeHeader();
     void escapeString(std::string& value);
     void writeValue(common::ValueVector* vector);
     void flush();
 
     template<typename T>
-    void writeToBuffer(common::ValueVector* vector, int64_t pos, bool escapeStringValue = false);
+    void writeToBuffer(common::ValueVector* vector, bool escapeStringValue = false);
 
     template<typename T>
-    void writeListToBuffer(common::ValueVector* vector, int64_t pos);
+    void writeListToBuffer(common::ValueVector* vector);
 
     inline void writeToBuffer(const std::string& value) { buffer << value; }
     inline void writeToBuffer(const char value) { buffer << value; }

src/include/processor/operator/persistent/file_writer.h

@@ -0,0 +1,27 @@
+#pragma once
+
+#include "common/copier_config/copier_config.h"
+#include "processor/result/result_set.h"
+
+namespace kuzu {
+namespace processor {
+
+class FileWriter {
+public:
+    FileWriter(std::string filePath, std::vector<std::string> columnNames,
+        std::vector<common::LogicalType> columnTypes)
+        : filePath{filePath}, columnNames{columnNames}, columnTypes{columnTypes} {}
+    virtual ~FileWriter(){};
+    virtual void init() = 0;
+    virtual void openFile() = 0;
+    virtual void closeFile() = 0;
+    virtual void writeValues(std::vector<common::ValueVector*>& outputVectors) = 0;
+
+protected:
+    std::string filePath;
+    std::vector<std::string> columnNames;
+    std::vector<common::LogicalType> columnTypes;
+};
+
+} // namespace processor
+} // namespace kuzu

src/include/processor/operator/persistent/parquet_column_writer.h

@@ -0,0 +1,76 @@
+#pragma once
+
+#include "common/types/date_t.h"
+#include "common/types/timestamp_t.h"
+#include "processor/operator/persistent/file_writer.h"
+#include <parquet/api/writer.h>
+
+namespace kuzu {
+namespace processor {
+
+// Kuzu column represents a single column in Kuzu, which may contains multiple Parquet columns
+// writeColumn will be called for each Kuzu column.
+class ParquetColumnWriter {
+public:
+    ParquetColumnWriter(int totalColumns, std::vector<int> maxDefinitionLevels)
+        : maxDefinitionLevels(maxDefinitionLevels), totalColumns(totalColumns){};
+
+    void writeColumn(
+        int column, common::ValueVector* vector, parquet::RowGroupWriter* rowGroupWriter);
+
+    int64_t estimatedRowBytes;
+
+private:
+    void nextParquetColumn(common::LogicalTypeID logicalTypeID);
+    void writePrimitiveValue(common::LogicalTypeID logicalTypeID, uint8_t* value,
+        int16_t definitionLevel = 0, int16_t repetitionLevel = 0);
+
+    // ParquetBatch contains the information needed by low-level arrow API writeBatch:
+    // WriteBatch(int64_t num_values, const int16_t* def_levels,
+    //               const int16_t* rep_levels, const T* values
+    struct ParquetColumn {
+        common::LogicalTypeID logicalTypeID;
+        std::vector<int16_t> repetitionLevels;
+        std::vector<int16_t> definitionLevels;
+        std::vector<uint8_t*> values;
+    };
+
+    void addToParquetColumns(uint8_t* value, common::ValueVector* vector,
+        std::map<std::string, ParquetColumn>& parquetColumns, int currentElementIdx = 0,
+        int parentElementIdx = 0, int depth = 0, std::string parentStructFieldName = "");
+
+    void extractList(const common::list_entry_t& list, const common::ValueVector* vector,
+        std::map<std::string, ParquetColumn>& parquetColumns, int currentElementIdx = 0,
+        int parentElementIdx = 0, int depth = 0, std::string parentStructFieldName = "");
+
+    void extractStruct(const common::struct_entry_t& val, const common::ValueVector* vector,
+        std::map<std::string, ParquetColumn>& parquetColumns, int currentElementIdx = 0,
+        int parentElementIdx = 0, int depth = 0, std::string parentStructFieldName = "");
+
+    void extractNested(uint8_t* value, const common::ValueVector* vector,
+        std::map<std::string, ParquetColumn>& parquetColumns, int currentElementIdx = 0,
+        int parentElementIdx = 0, int depth = 0, std::string parentStructFieldName = "");
+
+    inline void initNewColumn() { isListStarting = true; }
+
+    void writeLittleEndianUint32(uint8_t* buffer, uint32_t value);
+
+    // Extract dremel encoding levels
+    int getRepetitionLevel(int currentElementIdx, int parentElementIdx, int depth);
+
+    std::vector<int> maxDefinitionLevels;
+
+    // Properties for nested lists and structs
+    bool isListStarting;
+
+    int currentColumn = 0;
+    int currentParquetColumn = 0;
+    int totalColumns = 0;
+
+    // define the writers
+    parquet::RowGroupWriter* rowGroupWriter;
+    parquet::ColumnWriter* columnWriter;
+};
+
+} // namespace processor
+} // namespace kuzu

src/include/processor/operator/persistent/parquet_file_writer.h

@@ -0,0 +1,58 @@
+#pragma once
+
+#include "arrow/io/file.h"
+#include "processor/operator/persistent/file_writer.h"
+#include "processor/operator/persistent/parquet_column_writer.h"
+#include <parquet/api/writer.h>
+
+namespace kuzu {
+namespace processor {
+
+// ParquetFileWriter performs the following:
+// openFile: opens the file and create an arrow::io::FileOutputStream object
+// init:
+//   - generate the schema
+//   - calculate the max definition levels and number of primitive nodes. The
+//     definition levels are used for nested types.
+//   - initialize parquetColumnWriter
+// writeValues : take a vector of ValueVector and pass to parquetColumnWriter
+// More information about the encoding:
+// https://parquet.apache.org/docs/file-format/data-pages/encodings
+class ParquetFileWriter : public FileWriter {
+public:
+    using FileWriter::FileWriter;
+    void openFile() final;
+    void init() final;
+    void closeFile() final;
+    void writeValues(std::vector<common::ValueVector*>& outputVectors) final;
+
+private:
+    static std::shared_ptr<parquet::schema::Node> createParquetSchemaNode(int& parquetColumnsCount,
+        std::string& columnName, const common::LogicalType& logicalType,
+        parquet::Repetition::type repetition = parquet::Repetition::REQUIRED, int length = -1);
+
+    static std::shared_ptr<parquet::schema::Node> createNestedNode(
+        int& parquetColumnsCount, std::string& columnName, const common::LogicalType& logicalType);
+
+    static std::shared_ptr<parquet::schema::Node> createPrimitiveNode(int& parquetColumnsCount,
+        std::string& columnName, const common::LogicalType& logicalType,
+        parquet::Repetition::type repetition, int length);
+
+    void writeValue(common::LogicalTypeID type, void* value);
+
+    void flush();
+
+    void generateSchema(
+        std::shared_ptr<parquet::schema::GroupNode>& schema, int& parquetColumnsCount);
+
+    std::shared_ptr<ParquetColumnWriter> parquetColumnWriter;
+
+    parquet::RowGroupWriter* rowGroupWriter;
+
+    std::shared_ptr<parquet::ParquetFileWriter> fileWriter;
+
+    std::shared_ptr<arrow::io::FileOutputStream> outFile;
+};
+
+} // namespace processor
+} // namespace kuzu