// Licensed to the Apache Software Foundation (ASF) under one

// or more contributor license agreements.  See the NOTICE file

// distributed with this work for additional information

// regarding copyright ownership.  The ASF licenses this file

// to you under the Apache License, Version 2.0 (the

// "License"); you may not use this file except in compliance

// with the License.  You may obtain a copy of the License at

//

//   http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing,

// software distributed under the License is distributed on an

// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

// KIND, either express or implied.  See the License for the

// specific language governing permissions and limitations

// under the License.

#include "format/table/iceberg_reader.h"

#include <gen_cpp/Descriptors_types.h>

#include <gen_cpp/Metrics_types.h>

#include <gen_cpp/PlanNodes_types.h>

#include <gen_cpp/parquet_types.h>

#include <glog/logging.h>

#include <parallel_hashmap/phmap.h>

#include <rapidjson/document.h>

#include <algorithm>

#include <cstring>

#include <functional>

#include <memory>

#include <set>

#include "common/compiler_util.h" // IWYU pragma: keep

#include "common/status.h"

#include "core/assert_cast.h"

#include "core/block/block.h"

#include "core/block/column_with_type_and_name.h"

#include "core/column/column.h"

#include "core/column/column_string.h"

#include "core/column/column_vector.h"

#include "core/data_type/data_type_factory.hpp"

#include "core/data_type/define_primitive_type.h"

#include "core/data_type/primitive_type.h"

#include "core/string_ref.h"

#include "exprs/aggregate/aggregate_function.h"

#include "format/format_common.h"

#include "format/generic_reader.h"

#include "format/orc/vorc_reader.h"

#include "format/parquet/schema_desc.h"

#include "format/parquet/vparquet_column_chunk_reader.h"

#include "format/table/deletion_vector_reader.h"

#include "format/table/iceberg/iceberg_orc_nested_column_utils.h"

#include "format/table/iceberg/iceberg_parquet_nested_column_utils.h"

#include "format/table/nested_column_access_helper.h"

#include "format/table/table_format_reader.h"

#include "runtime/runtime_state.h"

#include "util/coding.h"

namespace cctz {

#include "common/compile_check_begin.h"

class time_zone;

} // namespace cctz

namespace doris {

class RowDescriptor;

class SlotDescriptor;

class TupleDescriptor;

namespace io {

struct IOContext;

} // namespace io

class VExprContext;

} // namespace doris

namespace doris {

const std::string IcebergOrcReader::ICEBERG_ORC_ATTRIBUTE = "iceberg.id";

IcebergTableReader::IcebergTableReader(std::unique_ptr<GenericReader> file_format_reader,

                                       RuntimeProfile* profile, RuntimeState* state,

                                       const TFileScanRangeParams& params,

                                       const TFileRangeDesc& range, ShardedKVCache* kv_cache,

                                       io::IOContext* io_ctx, FileMetaCache* meta_cache)

        : TableFormatReader(std::move(file_format_reader), state, profile, params, range, io_ctx,

                            meta_cache),

          _kv_cache(kv_cache) {

    static const char* iceberg_profile = "IcebergProfile";

    ADD_TIMER(_profile, iceberg_profile);

    _iceberg_profile.num_delete_files =

            ADD_CHILD_COUNTER(_profile, "NumDeleteFiles", TUnit::UNIT, iceberg_profile);

    _iceberg_profile.num_delete_rows =

            ADD_CHILD_COUNTER(_profile, "NumDeleteRows", TUnit::UNIT, iceberg_profile);

    _iceberg_profile.delete_files_read_time =

            ADD_CHILD_TIMER(_profile, "DeleteFileReadTime", iceberg_profile);

    _iceberg_profile.delete_rows_sort_time =

            ADD_CHILD_TIMER(_profile, "DeleteRowsSortTime", iceberg_profile);

    _iceberg_profile.parse_delete_file_time =

            ADD_CHILD_TIMER(_profile, "ParseDeleteFileTime", iceberg_profile);

}

Status IcebergTableReader::get_next_block_inner(Block* block, size_t* read_rows, bool* eof) {

    RETURN_IF_ERROR(_expand_block_if_need(block));

    RETURN_IF_ERROR(_file_format_reader->get_next_block(block, read_rows, eof));

    if (_equality_delete_impls.size() > 0) {

        std::unique_ptr<IColumn::Filter> filter =

                std::make_unique<IColumn::Filter>(block->rows(), 1);

        for (auto& equality_delete_impl : _equality_delete_impls) {

            RETURN_IF_ERROR(equality_delete_impl->filter_data_block(

                    block, _col_name_to_block_idx, _id_to_block_column_name, *filter));

        }

        Block::filter_block_internal(block, *filter, block->columns());

    }

    *read_rows = block->rows();

    return _shrink_block_if_need(block);

}

Status IcebergTableReader::init_row_filters() {

    // We get the count value by doris's be, so we don't need to read the delete file

    if (_push_down_agg_type == TPushAggOp::type::COUNT && _table_level_row_count > 0) {

        return Status::OK();

    }

    const auto& table_desc = _range.table_format_params.iceberg_params;

    const auto& version = table_desc.format_version;

    if (version < MIN_SUPPORT_DELETE_FILES_VERSION) {

        return Status::OK();

    }

    // Initialize file information for $row_id generation

    // Extract from table_desc which contains current file's metadata

    if (_need_row_id_column) {

        std::string file_path = table_desc.original_file_path;

        int32_t partition_spec_id = 0;

        std::string partition_data_json;

        if (table_desc.__isset.partition_spec_id) {

            partition_spec_id = table_desc.partition_spec_id;

        }

        if (table_desc.__isset.partition_data_json) {

            partition_data_json = table_desc.partition_data_json;

        }

        if (auto* parquet_reader = dynamic_cast<ParquetReader*>(_file_format_reader.get())) {

            parquet_reader->set_iceberg_rowid_params(file_path, partition_spec_id,

                                                     partition_data_json, _row_id_column_position);

        } else if (auto* orc_reader = dynamic_cast<OrcReader*>(_file_format_reader.get())) {

            orc_reader->set_iceberg_rowid_params(file_path, partition_spec_id, partition_data_json,

                                                 _row_id_column_position);

        }

        LOG(INFO) << "Initialized $row_id generation for file: " << file_path

                  << ", partition_spec_id: " << partition_spec_id;

    }

    std::vector<TIcebergDeleteFileDesc> position_delete_files;

    std::vector<TIcebergDeleteFileDesc> equality_delete_files;

    std::vector<TIcebergDeleteFileDesc> deletion_vector_files;

    for (const TIcebergDeleteFileDesc& desc : table_desc.delete_files) {

        if (desc.content == POSITION_DELETE) {

            position_delete_files.emplace_back(desc);

        } else if (desc.content == EQUALITY_DELETE) {

            equality_delete_files.emplace_back(desc);

        } else if (desc.content == DELETION_VECTOR) {

            deletion_vector_files.emplace_back(desc);

        }

    }

    if (!equality_delete_files.empty()) {

        RETURN_IF_ERROR(_process_equality_delete(equality_delete_files));

        _file_format_reader->set_push_down_agg_type(TPushAggOp::NONE);

    }

    if (!deletion_vector_files.empty()) {

        if (deletion_vector_files.size() != 1) [[unlikely]] {

            /*

             * Deletion vectors are a binary representation of deletes for a single data file that is more efficient

             * at execution time than position delete files. Unlike equality or position delete files, there can be

             * at most one deletion vector for a given data file in a snapshot.

             */

            return Status::DataQualityError("This iceberg data file has multiple DVs.");

        }

        RETURN_IF_ERROR(

                read_deletion_vector(table_desc.original_file_path, deletion_vector_files[0]));

        _file_format_reader->set_push_down_agg_type(TPushAggOp::NONE);

        // Readers can safely ignore position delete files if there is a DV for a data file.

    } else if (!position_delete_files.empty()) {

        RETURN_IF_ERROR(

                _position_delete_base(table_desc.original_file_path, position_delete_files));

        _file_format_reader->set_push_down_agg_type(TPushAggOp::NONE);

    }

    COUNTER_UPDATE(_iceberg_profile.num_delete_files, table_desc.delete_files.size());

    return Status::OK();

}

void IcebergTableReader::_generate_equality_delete_block(

        Block* block, const std::vector<std::string>& equality_delete_col_names,

        const std::vector<DataTypePtr>& equality_delete_col_types) {

    for (int i = 0; i < equality_delete_col_names.size(); ++i) {

        DataTypePtr data_type = make_nullable(equality_delete_col_types[i]);

        MutableColumnPtr data_column = data_type->create_column();

        block->insert(ColumnWithTypeAndName(std::move(data_column), data_type,

                                            equality_delete_col_names[i]));

    }

}

Status IcebergTableReader::_expand_block_if_need(Block* block) {

    std::set<std::string> names;

    auto block_names = block->get_names();

    names.insert(block_names.begin(), block_names.end());

    for (auto& col : _expand_columns) {

        col.column->assume_mutable()->clear();

        if (names.contains(col.name)) {

            return Status::InternalError("Wrong expand column '{}'", col.name);

        }

        names.insert(col.name);

        (*_col_name_to_block_idx)[col.name] = static_cast<uint32_t>(block->columns());

        block->insert(col);

    }

    return Status::OK();

}

Status IcebergTableReader::_shrink_block_if_need(Block* block) {

    std::set<size_t> positions_to_erase;

    for (const std::string& expand_col : _expand_col_names) {

        if (!_col_name_to_block_idx->contains(expand_col)) {

            return Status::InternalError("Wrong erase column '{}', block: {}", expand_col,

                                         block->dump_names());

        }

        positions_to_erase.emplace((*_col_name_to_block_idx)[expand_col]);

    }

    block->erase(positions_to_erase);

    for (const std::string& expand_col : _expand_col_names) {

        _col_name_to_block_idx->erase(expand_col);

    }

    return Status::OK();

}

Status IcebergTableReader::_position_delete_base(

        const std::string data_file_path, const std::vector<TIcebergDeleteFileDesc>& delete_files) {

    std::vector<DeleteRows*> delete_rows_array;

    int64_t num_delete_rows = 0;

    for (const auto& delete_file : delete_files) {

        SCOPED_TIMER(_iceberg_profile.delete_files_read_time);

        Status create_status = Status::OK();

        auto* delete_file_cache = _kv_cache->get<DeleteFile>(

                _delet_file_cache_key(delete_file.path), [&]() -> DeleteFile* {

                    auto* position_delete = new DeleteFile;

                    TFileRangeDesc delete_file_range;

                    // must use __set() method to make sure __isset is true

                    delete_file_range.__set_fs_name(_range.fs_name);

                    delete_file_range.path = delete_file.path;

                    delete_file_range.start_offset = 0;

                    delete_file_range.size = -1;

                    delete_file_range.file_size = -1;

                    //read position delete file base on delete_file_range , generate DeleteFile , add DeleteFile to kv_cache

                    create_status = _read_position_delete_file(&delete_file_range, position_delete);

                    if (!create_status) {

                        return nullptr;

                    }

                    return position_delete;

                });

        if (create_status.is<ErrorCode::END_OF_FILE>()) {

            continue;

        } else if (!create_status.ok()) {

            return create_status;

        }

        DeleteFile& delete_file_map = *((DeleteFile*)delete_file_cache);

        auto get_value = [&](const auto& v) {

            DeleteRows* row_ids = v.second.get();

            if (!row_ids->empty()) {

                delete_rows_array.emplace_back(row_ids);

                num_delete_rows += row_ids->size();

            }

        };

        delete_file_map.if_contains(data_file_path, get_value);

    }

    // Use a KV cache to store the delete rows corresponding to a data file path.

    // The Parquet/ORC reader holds a reference (pointer) to this cached entry.

    // This allows delete rows to be reused when a single data file is split into

    // multiple splits, avoiding excessive memory usage when delete rows are large.

    if (num_delete_rows > 0) {

        SCOPED_TIMER(_iceberg_profile.delete_rows_sort_time);

        _iceberg_delete_rows =

                _kv_cache->get<DeleteRows>(data_file_path,

                                           [&]() -> DeleteRows* {

                                               auto* data_file_position_delete = new DeleteRows;

                                               _sort_delete_rows(delete_rows_array, num_delete_rows,

                                                                 *data_file_position_delete);

                                               return data_file_position_delete;

                                           }

                );

        set_delete_rows();

        COUNTER_UPDATE(_iceberg_profile.num_delete_rows, num_delete_rows);

    }

    return Status::OK();

}

IcebergTableReader::PositionDeleteRange IcebergTableReader::_get_range(

        const ColumnDictI32& file_path_column) {

    IcebergTableReader::PositionDeleteRange range;

    size_t read_rows = file_path_column.get_data().size();

    const int* code_path = file_path_column.get_data().data();

    const int* code_path_start = code_path;

    const int* code_path_end = code_path + read_rows;

    while (code_path < code_path_end) {

        int code = code_path[0];

        const int* code_end = std::upper_bound(code_path, code_path_end, code);

        range.data_file_path.emplace_back(file_path_column.get_value(code).to_string());

        range.range.emplace_back(code_path - code_path_start, code_end - code_path_start);

        code_path = code_end;

    }

    return range;

}

IcebergTableReader::PositionDeleteRange IcebergTableReader::_get_range(

        const ColumnString& file_path_column) {

    IcebergTableReader::PositionDeleteRange range;

    size_t read_rows = file_path_column.size();

    size_t index = 0;

    while (index < read_rows) {

        StringRef data_path = file_path_column.get_data_at(index);

        size_t left = index - 1;

        size_t right = read_rows;

        while (left + 1 != right) {

            size_t mid = left + (right - left) / 2;

            if (file_path_column.get_data_at(mid) > data_path) {

                right = mid;

            } else {

                left = mid;

            }

        }

        range.data_file_path.emplace_back(data_path.to_string());

        range.range.emplace_back(index, left + 1);

        index = left + 1;

    }

    return range;

}

/**

 * https://iceberg.apache.org/spec/#position-delete-files

 * The rows in the delete file must be sorted by file_path then position to optimize filtering rows while scanning.

 * Sorting by file_path allows filter pushdown by file in columnar storage formats.

 * Sorting by position allows filtering rows while scanning, to avoid keeping deletes in memory.

 */

void IcebergTableReader::_sort_delete_rows(

        const std::vector<std::vector<int64_t>*>& delete_rows_array, int64_t num_delete_rows,

        std::vector<int64_t>& result) {

    if (delete_rows_array.empty()) {

        return;

    }

    if (delete_rows_array.size() == 1) {

        result.resize(num_delete_rows);

        memcpy(result.data(), delete_rows_array.front()->data(), sizeof(int64_t) * num_delete_rows);

        return;

    }

    if (delete_rows_array.size() == 2) {

        result.resize(num_delete_rows);

        std::merge(delete_rows_array.front()->begin(), delete_rows_array.front()->end(),

                   delete_rows_array.back()->begin(), delete_rows_array.back()->end(),

                   result.begin());

        return;

    }

    using vec_pair = std::pair<std::vector<int64_t>::iterator, std::vector<int64_t>::iterator>;

    result.resize(num_delete_rows);

    auto row_id_iter = result.begin();

    auto iter_end = result.end();

    std::vector<vec_pair> rows_array;

    for (auto* rows : delete_rows_array) {

        if (!rows->empty()) {

            rows_array.emplace_back(rows->begin(), rows->end());

        }

    }

    size_t array_size = rows_array.size();

    while (row_id_iter != iter_end) {

        int64_t min_index = 0;

        int64_t min = *rows_array[0].first;

        for (size_t i = 0; i < array_size; ++i) {

            if (*rows_array[i].first < min) {

                min_index = i;

                min = *rows_array[i].first;

            }

        }

        *row_id_iter++ = min;

        rows_array[min_index].first++;

        if (UNLIKELY(rows_array[min_index].first == rows_array[min_index].second)) {

            rows_array.erase(rows_array.begin() + min_index);

            array_size--;

        }

    }

}

void IcebergTableReader::_gen_position_delete_file_range(Block& block, DeleteFile* position_delete,

                                                         size_t read_rows,

                                                         bool file_path_column_dictionary_coded) {

    SCOPED_TIMER(_iceberg_profile.parse_delete_file_time);

    // todo: maybe do not need to build name to index map every time

    auto name_to_pos_map = block.get_name_to_pos_map();

    ColumnPtr path_column = block.get_by_position(name_to_pos_map[ICEBERG_FILE_PATH]).column;

    DCHECK_EQ(path_column->size(), read_rows);

    ColumnPtr pos_column = block.get_by_position(name_to_pos_map[ICEBERG_ROW_POS]).column;

    using ColumnType = typename PrimitiveTypeTraits<TYPE_BIGINT>::ColumnType;

    const int64_t* src_data = assert_cast<const ColumnType&>(*pos_column).get_data().data();

    IcebergTableReader::PositionDeleteRange range;

    if (file_path_column_dictionary_coded) {

        range = _get_range(assert_cast<const ColumnDictI32&>(*path_column));

    } else {

        range = _get_range(assert_cast<const ColumnString&>(*path_column));

    }

    for (int i = 0; i < range.range.size(); ++i) {

        std::string key = range.data_file_path[i];

        auto iter = position_delete->find(key);

        DeleteRows* delete_rows;

        if (iter == position_delete->end()) {

            delete_rows = new DeleteRows;

            std::unique_ptr<DeleteRows> delete_rows_ptr(delete_rows);

            (*position_delete)[key] = std::move(delete_rows_ptr);

        } else {

            delete_rows = iter->second.get();

        }

        const int64_t* cpy_start = src_data + range.range[i].first;

        const int64_t cpy_count = range.range[i].second - range.range[i].first;

        int64_t origin_size = delete_rows->size();

        delete_rows->resize(origin_size + cpy_count);

        int64_t* dest_position = &(*delete_rows)[origin_size];

        memcpy(dest_position, cpy_start, cpy_count * sizeof(int64_t));

    }

}

Status IcebergParquetReader::init_reader(

        const std::vector<std::string>& file_col_names,

        std::unordered_map<std::string, uint32_t>* col_name_to_block_idx,

        const VExprContextSPtrs& conjuncts,

        phmap::flat_hash_map<int, std::vector<std::shared_ptr<ColumnPredicate>>>&

                slot_id_to_predicates,

        const TupleDescriptor* tuple_descriptor, const RowDescriptor* row_descriptor,

        const std::unordered_map<std::string, int>* colname_to_slot_id,

        const VExprContextSPtrs* not_single_slot_filter_conjuncts,

        const std::unordered_map<int, VExprContextSPtrs>* slot_id_to_filter_conjuncts) {

    _file_format = Fileformat::PARQUET;

    _col_name_to_block_idx = col_name_to_block_idx;

    auto* parquet_reader = static_cast<ParquetReader*>(_file_format_reader.get());

    RETURN_IF_ERROR(parquet_reader->get_file_metadata_schema(&_data_file_field_desc));

    DCHECK(_data_file_field_desc != nullptr);

    auto column_id_result = _create_column_ids(_data_file_field_desc, tuple_descriptor);

    auto& column_ids = column_id_result.column_ids;

    const auto& filter_column_ids = column_id_result.filter_column_ids;

    RETURN_IF_ERROR(init_row_filters());

    _all_required_col_names = file_col_names;

    if (!_params.__isset.history_schema_info || _params.history_schema_info.empty()) [[unlikely]] {

        RETURN_IF_ERROR(BuildTableInfoUtil::by_parquet_name(

                tuple_descriptor, *_data_file_field_desc, table_info_node_ptr));

    } else {

        std::set<std::string> read_col_name_set(file_col_names.begin(), file_col_names.end());

        bool exist_field_id = true;

        for (int idx = 0; idx < _data_file_field_desc->size(); idx++) {

            if (_data_file_field_desc->get_column(idx)->field_id == -1) {

                // the data file may be from hive table migrated to iceberg, field id is missing

                exist_field_id = false;

                break;

            }

        }

        const auto& table_schema = _params.history_schema_info.front().root_field;

        table_info_node_ptr = std::make_shared<TableSchemaChangeHelper::StructNode>();

        if (exist_field_id) {

            // id -> table column name. columns that need read data file.

            std::unordered_map<int, std::shared_ptr<schema::external::TField>> id_to_table_field;

            for (const auto& table_field : table_schema.fields) {

                auto field = table_field.field_ptr;

                DCHECK(field->__isset.name);

                if (!read_col_name_set.contains(field->name)) {

                    continue;

                }

                id_to_table_field.emplace(field->id, field);

            }

            for (int idx = 0; idx < _data_file_field_desc->size(); idx++) {

                const auto& data_file_field = _data_file_field_desc->get_column(idx);

                auto data_file_column_id = _data_file_field_desc->get_column(idx)->field_id;

                if (id_to_table_field.contains(data_file_column_id)) {

                    const auto& table_field = id_to_table_field[data_file_column_id];

                    std::shared_ptr<TableSchemaChangeHelper::Node> field_node = nullptr;

                    RETURN_IF_ERROR(BuildTableInfoUtil::by_parquet_field_id(

                            *table_field, *data_file_field, exist_field_id, field_node));

                    table_info_node_ptr->add_children(table_field->name, data_file_field->name,

                                                      field_node);

                    _id_to_block_column_name.emplace(data_file_column_id, table_field->name);

                    id_to_table_field.erase(data_file_column_id);

                } else if (_equality_delete_col_ids.contains(data_file_column_id)) {

                    // Columns that need to be read for equality delete.

                    const static std::string EQ_DELETE_PRE = "__equality_delete_column__";

                    // Construct table column names that avoid duplication with current table schema.

                    // As the columns currently being read may have been deleted in the latest

                    // table structure or have undergone a series of schema changes...

                    std::string table_column_name = EQ_DELETE_PRE + data_file_field->name;

                    table_info_node_ptr->add_children(

                            table_column_name, data_file_field->name,

                            std::make_shared<TableSchemaChangeHelper::ConstNode>());

                    _id_to_block_column_name.emplace(data_file_column_id, table_column_name);

                    _expand_col_names.emplace_back(table_column_name);

                    auto expand_data_type = make_nullable(data_file_field->data_type);

                    _expand_columns.emplace_back(

                            ColumnWithTypeAndName {expand_data_type->create_column(),

                                                   expand_data_type, table_column_name});

                    _all_required_col_names.emplace_back(table_column_name);

                    column_ids.insert(data_file_field->get_column_id());

                }

            }

            for (const auto& [id, table_field] : id_to_table_field) {

                table_info_node_ptr->add_not_exist_children(table_field->name);

            }

        } else {

            if (!_equality_delete_col_ids.empty()) [[unlikely]] {

                return Status::InternalError(

                        "Can not read missing field id data file when have equality delete");

            }

            std::map<std::string, size_t> file_column_idx_map;

            for (size_t idx = 0; idx < _data_file_field_desc->size(); idx++) {

                file_column_idx_map.emplace(_data_file_field_desc->get_column(idx)->name, idx);

            }

            for (const auto& table_field : table_schema.fields) {

                DCHECK(table_field.__isset.field_ptr);

                DCHECK(table_field.field_ptr->__isset.name);

                const auto& table_column_name = table_field.field_ptr->name;

                if (!read_col_name_set.contains(table_column_name)) {

                    continue;

                }

                if (!table_field.field_ptr->__isset.name_mapping ||

                    table_field.field_ptr->name_mapping.size() == 0) {

                    return Status::DataQualityError(

                            "name_mapping must be set when read missing field id data file.");

                }

                bool have_mapping = false;

                for (const auto& mapped_name : table_field.field_ptr->name_mapping) {

                    if (file_column_idx_map.contains(mapped_name)) {

                        std::shared_ptr<TableSchemaChangeHelper::Node> field_node = nullptr;

                        const auto& file_field = _data_file_field_desc->get_column(

                                file_column_idx_map.at(mapped_name));

                        RETURN_IF_ERROR(BuildTableInfoUtil::by_parquet_field_id(

                                *table_field.field_ptr, *file_field, exist_field_id, field_node));

                        table_info_node_ptr->add_children(table_column_name, file_field->name,

                                                          field_node);

                        have_mapping = true;

                        break;

                    }

                }

                if (!have_mapping) {

                    table_info_node_ptr->add_not_exist_children(table_column_name);

                }

            }

        }

    }

    return parquet_reader->init_reader(

            _all_required_col_names, _col_name_to_block_idx, conjuncts, slot_id_to_predicates,

            tuple_descriptor, row_descriptor, colname_to_slot_id, not_single_slot_filter_conjuncts,

            slot_id_to_filter_conjuncts, table_info_node_ptr, true, column_ids, filter_column_ids);

}

ColumnIdResult IcebergParquetReader::_create_column_ids(const FieldDescriptor* field_desc,

                                                        const TupleDescriptor* tuple_descriptor) {

    // First, assign column IDs to the field descriptor

    auto* mutable_field_desc = const_cast<FieldDescriptor*>(field_desc);

    mutable_field_desc->assign_ids();

    // map top-level table column iceberg_id -> FieldSchema*

    std::unordered_map<int, const FieldSchema*> iceberg_id_to_field_schema_map;

    for (int i = 0; i < field_desc->size(); ++i) {

        auto field_schema = field_desc->get_column(i);

        if (!field_schema) continue;

        int iceberg_id = field_schema->field_id;

        iceberg_id_to_field_schema_map[iceberg_id] = field_schema;

    }

    std::set<uint64_t> column_ids;

    std::set<uint64_t> filter_column_ids;

    // helper to process access paths for a given top-level parquet field

    auto process_access_paths = [](const FieldSchema* parquet_field,

                                   const std::vector<TColumnAccessPath>& access_paths,

                                   std::set<uint64_t>& out_ids) {

        process_nested_access_paths(

                parquet_field, access_paths, out_ids,

                [](const FieldSchema* field) { return field->get_column_id(); },

                [](const FieldSchema* field) { return field->get_max_column_id(); },

                IcebergParquetNestedColumnUtils::extract_nested_column_ids);

    };

    for (const auto* slot : tuple_descriptor->slots()) {

        auto it = iceberg_id_to_field_schema_map.find(slot->col_unique_id());

        if (it == iceberg_id_to_field_schema_map.end()) {

            // Column not found in file (e.g., partition column, added column)

            continue;

        }

        auto field_schema = it->second;

        // primitive (non-nested) types: direct mapping by name

        if ((slot->col_type() != TYPE_STRUCT && slot->col_type() != TYPE_ARRAY &&

             slot->col_type() != TYPE_MAP)) {

            column_ids.insert(field_schema->column_id);

            if (slot->is_predicate()) {

                filter_column_ids.insert(field_schema->column_id);

            }

            continue;

        }

        // complex types:

        const auto& all_access_paths = slot->all_access_paths();

        process_access_paths(field_schema, all_access_paths, column_ids);

        const auto& predicate_access_paths = slot->predicate_access_paths();

        if (!predicate_access_paths.empty()) {

            process_access_paths(field_schema, predicate_access_paths, filter_column_ids);

        }

    }

    return ColumnIdResult(std::move(column_ids), std::move(filter_column_ids));

}

Status IcebergParquetReader ::_read_position_delete_file(const TFileRangeDesc* delete_range,

                                                         DeleteFile* position_delete) {

    ParquetReader parquet_delete_reader(_profile, _params, *delete_range,

                                        READ_DELETE_FILE_BATCH_SIZE, &_state->timezone_obj(),

                                        _io_ctx, _state, _meta_cache);

    phmap::flat_hash_map<int, std::vector<std::shared_ptr<ColumnPredicate>>> tmp;

    RETURN_IF_ERROR(parquet_delete_reader.init_reader(

            delete_file_col_names,

            const_cast<std::unordered_map<std::string, uint32_t>*>(&DELETE_COL_NAME_TO_BLOCK_IDX),

            {}, tmp, nullptr, nullptr, nullptr, nullptr, nullptr,

            TableSchemaChangeHelper::ConstNode::get_instance(), false));

    std::unordered_map<std::string, std::tuple<std::string, const SlotDescriptor*>>

            partition_columns;

    std::unordered_map<std::string, VExprContextSPtr> missing_columns;

    RETURN_IF_ERROR(parquet_delete_reader.set_fill_columns(partition_columns, missing_columns));

    const tparquet::FileMetaData* meta_data = parquet_delete_reader.get_meta_data();

    bool dictionary_coded = true;

    for (const auto& row_group : meta_data->row_groups) {

        const auto& column_chunk = row_group.columns[ICEBERG_FILE_PATH_INDEX];

        if (!(column_chunk.__isset.meta_data && has_dict_page(column_chunk.meta_data))) {

            dictionary_coded = false;

            break;

        }

    }

    DataTypePtr data_type_file_path {new DataTypeString};

    DataTypePtr data_type_pos {new DataTypeInt64};

    bool eof = false;

    while (!eof) {

        Block block = {dictionary_coded

                               ? ColumnWithTypeAndName {ColumnDictI32::create(

                                                                FieldType::OLAP_FIELD_TYPE_VARCHAR),

                                                        data_type_file_path, ICEBERG_FILE_PATH}

                               : ColumnWithTypeAndName {data_type_file_path, ICEBERG_FILE_PATH},

                       {data_type_pos, ICEBERG_ROW_POS}};

        size_t read_rows = 0;

        RETURN_IF_ERROR(parquet_delete_reader.get_next_block(&block, &read_rows, &eof));

        if (read_rows <= 0) {

            break;

        }

        _gen_position_delete_file_range(block, position_delete, read_rows, dictionary_coded);

    }

    return Status::OK();

};

Status IcebergOrcReader::init_reader(

        const std::vector<std::string>& file_col_names,

        std::unordered_map<std::string, uint32_t>* col_name_to_block_idx,

        const VExprContextSPtrs& conjuncts, const TupleDescriptor* tuple_descriptor,

        const RowDescriptor* row_descriptor,

        const std::unordered_map<std::string, int>* colname_to_slot_id,

        const VExprContextSPtrs* not_single_slot_filter_conjuncts,

        const std::unordered_map<int, VExprContextSPtrs>* slot_id_to_filter_conjuncts) {

    _file_format = Fileformat::ORC;

    _col_name_to_block_idx = col_name_to_block_idx;

    auto* orc_reader = static_cast<OrcReader*>(_file_format_reader.get());

    RETURN_IF_ERROR(orc_reader->get_file_type(&_data_file_type_desc));

    std::vector<std::string> data_file_col_names;

    std::vector<DataTypePtr> data_file_col_types;

    RETURN_IF_ERROR(orc_reader->get_parsed_schema(&data_file_col_names, &data_file_col_types));

    auto column_id_result = _create_column_ids(_data_file_type_desc, tuple_descriptor);

    auto& column_ids = column_id_result.column_ids;

    const auto& filter_column_ids = column_id_result.filter_column_ids;

    RETURN_IF_ERROR(init_row_filters());

    _all_required_col_names = file_col_names;

    if (!_params.__isset.history_schema_info || _params.history_schema_info.empty()) [[unlikely]] {

        RETURN_IF_ERROR(BuildTableInfoUtil::by_orc_name(tuple_descriptor, _data_file_type_desc,

                                                        table_info_node_ptr));

    } else {

        std::set<std::string> read_col_name_set(file_col_names.begin(), file_col_names.end());

        bool exist_field_id = true;

        for (size_t idx = 0; idx < _data_file_type_desc->getSubtypeCount(); idx++) {

            if (!_data_file_type_desc->getSubtype(idx)->hasAttributeKey(ICEBERG_ORC_ATTRIBUTE)) {

                exist_field_id = false;

                break;

            }

        }

        const auto& table_schema = _params.history_schema_info.front().root_field;

        table_info_node_ptr = std::make_shared<TableSchemaChangeHelper::StructNode>();

        if (exist_field_id) {

            // id -> table column name. columns that need read data file.

            std::unordered_map<int, std::shared_ptr<schema::external::TField>> id_to_table_field;

            for (const auto& table_field : table_schema.fields) {

                auto field = table_field.field_ptr;

                DCHECK(field->__isset.name);

                if (!read_col_name_set.contains(field->name)) {

                    continue;

                }

                id_to_table_field.emplace(field->id, field);

            }

            for (int idx = 0; idx < _data_file_type_desc->getSubtypeCount(); idx++) {

                const auto& data_file_field = _data_file_type_desc->getSubtype(idx);

                auto data_file_column_id =

                        std::stoi(data_file_field->getAttributeValue(ICEBERG_ORC_ATTRIBUTE));

                auto const& file_column_name = _data_file_type_desc->getFieldName(idx);

                if (id_to_table_field.contains(data_file_column_id)) {

                    const auto& table_field = id_to_table_field[data_file_column_id];

                    std::shared_ptr<TableSchemaChangeHelper::Node> field_node = nullptr;

                    RETURN_IF_ERROR(BuildTableInfoUtil::by_orc_field_id(

                            *table_field, data_file_field, ICEBERG_ORC_ATTRIBUTE, exist_field_id,

                            field_node));

                    table_info_node_ptr->add_children(table_field->name, file_column_name,

                                                      field_node);

                    _id_to_block_column_name.emplace(data_file_column_id, table_field->name);

                    id_to_table_field.erase(data_file_column_id);

                } else if (_equality_delete_col_ids.contains(data_file_column_id)) {

                    // Columns that need to be read for equality delete.

                    const static std::string EQ_DELETE_PRE = "__equality_delete_column__";

                    // Construct table column names that avoid duplication with current table schema.

                    // As the columns currently being read may have been deleted in the latest

                    // table structure or have undergone a series of schema changes...

                    std::string table_column_name = EQ_DELETE_PRE + file_column_name;

                    table_info_node_ptr->add_children(

                            table_column_name, file_column_name,

                            std::make_shared<TableSchemaChangeHelper::ConstNode>());

                    _id_to_block_column_name.emplace(data_file_column_id, table_column_name);

                    _expand_col_names.emplace_back(table_column_name);

                    auto expand_data_type = make_nullable(data_file_col_types[idx]);

                    _expand_columns.emplace_back(

                            ColumnWithTypeAndName {expand_data_type->create_column(),

                                                   expand_data_type, table_column_name});

                    _all_required_col_names.emplace_back(table_column_name);

                    column_ids.insert(data_file_field->getColumnId());

                }

            }

            for (const auto& [id, table_field] : id_to_table_field) {

                table_info_node_ptr->add_not_exist_children(table_field->name);

            }

        } else {

            if (!_equality_delete_col_ids.empty()) [[unlikely]] {

                return Status::InternalError(

                        "Can not read missing field id data file when have equality delete");

            }

            std::map<std::string, size_t> file_column_idx_map;

            for (int idx = 0; idx < _data_file_type_desc->getSubtypeCount(); idx++) {

                auto const& file_column_name = _data_file_type_desc->getFieldName(idx);

                file_column_idx_map.emplace(file_column_name, idx);

            }

            for (const auto& table_field : table_schema.fields) {

                DCHECK(table_field.__isset.field_ptr);

                DCHECK(table_field.field_ptr->__isset.name);

                const auto& table_column_name = table_field.field_ptr->name;

                if (!read_col_name_set.contains(table_column_name)) {

                    continue;

                }

                if (!table_field.field_ptr->__isset.name_mapping ||

                    table_field.field_ptr->name_mapping.size() == 0) {

                    return Status::DataQualityError(

                            "name_mapping must be set when read missing field id data file.");

                }

                auto have_mapping = false;

                for (const auto& mapped_name : table_field.field_ptr->name_mapping) {

                    if (file_column_idx_map.contains(mapped_name)) {

                        auto file_column_idx = file_column_idx_map.at(mapped_name);

                        std::shared_ptr<TableSchemaChangeHelper::Node> field_node = nullptr;

                        const auto& file_field = _data_file_type_desc->getSubtype(file_column_idx);

                        RETURN_IF_ERROR(BuildTableInfoUtil::by_orc_field_id(

                                *table_field.field_ptr, file_field, ICEBERG_ORC_ATTRIBUTE,

                                exist_field_id, field_node));

                        table_info_node_ptr->add_children(

                                table_column_name,

                                _data_file_type_desc->getFieldName(file_column_idx), field_node);

                        have_mapping = true;

                        break;

                    }

                }

                if (!have_mapping) {

                    table_info_node_ptr->add_not_exist_children(table_column_name);

                }

            }

        }

    }

    return orc_reader->init_reader(&_all_required_col_names, _col_name_to_block_idx, conjuncts,

                                   false, tuple_descriptor, row_descriptor,

                                   not_single_slot_filter_conjuncts, slot_id_to_filter_conjuncts,

                                   table_info_node_ptr, column_ids, filter_column_ids);

}

ColumnIdResult IcebergOrcReader::_create_column_ids(const orc::Type* orc_type,

                                                    const TupleDescriptor* tuple_descriptor) {

    // map top-level table column iceberg_id -> orc::Type*

    std::unordered_map<int, const orc::Type*> iceberg_id_to_orc_type_map;

    for (uint64_t i = 0; i < orc_type->getSubtypeCount(); ++i) {

        auto orc_sub_type = orc_type->getSubtype(i);

        if (!orc_sub_type) continue;

        if (!orc_sub_type->hasAttributeKey(ICEBERG_ORC_ATTRIBUTE)) {

            continue;

        }

        int iceberg_id = std::stoi(orc_sub_type->getAttributeValue(ICEBERG_ORC_ATTRIBUTE));

        iceberg_id_to_orc_type_map[iceberg_id] = orc_sub_type;

    }

    std::set<uint64_t> column_ids;

    std::set<uint64_t> filter_column_ids;

    // helper to process access paths for a given top-level orc field

    auto process_access_paths = [](const orc::Type* orc_field,

                                   const std::vector<TColumnAccessPath>& access_paths,

                                   std::set<uint64_t>& out_ids) {

        process_nested_access_paths(

                orc_field, access_paths, out_ids,

                [](const orc::Type* type) { return type->getColumnId(); },

                [](const orc::Type* type) { return type->getMaximumColumnId(); },

                IcebergOrcNestedColumnUtils::extract_nested_column_ids);

    };

    for (const auto* slot : tuple_descriptor->slots()) {

        auto it = iceberg_id_to_orc_type_map.find(slot->col_unique_id());

        if (it == iceberg_id_to_orc_type_map.end()) {

            // Column not found in file

            continue;

        }

        const orc::Type* orc_field = it->second;

        // primitive (non-nested) types

        if ((slot->col_type() != TYPE_STRUCT && slot->col_type() != TYPE_ARRAY &&

             slot->col_type() != TYPE_MAP)) {

            column_ids.insert(orc_field->getColumnId());

            if (slot->is_predicate()) {

                filter_column_ids.insert(orc_field->getColumnId());

            }

            continue;

        }

        // complex types

        const auto& all_access_paths = slot->all_access_paths();

        process_access_paths(orc_field, all_access_paths, column_ids);

        const auto& predicate_access_paths = slot->predicate_access_paths();

        if (!predicate_access_paths.empty()) {

            process_access_paths(orc_field, predicate_access_paths, filter_column_ids);

        }

    }

    return ColumnIdResult(std::move(column_ids), std::move(filter_column_ids));

}

Status IcebergOrcReader::_read_position_delete_file(const TFileRangeDesc* delete_range,

                                                    DeleteFile* position_delete) {

    OrcReader orc_delete_reader(_profile, _state, _params, *delete_range,

                                READ_DELETE_FILE_BATCH_SIZE, _state->timezone(), _io_ctx,

                                _meta_cache);

    RETURN_IF_ERROR(orc_delete_reader.init_reader(

            &delete_file_col_names,

            const_cast<std::unordered_map<std::string, uint32_t>*>(&DELETE_COL_NAME_TO_BLOCK_IDX),

            {}, false, {}, {}, nullptr, nullptr));

    std::unordered_map<std::string, std::tuple<std::string, const SlotDescriptor*>>

            partition_columns;

    std::unordered_map<std::string, VExprContextSPtr> missing_columns;

    RETURN_IF_ERROR(orc_delete_reader.set_fill_columns(partition_columns, missing_columns));

    bool eof = false;

    DataTypePtr data_type_file_path {new DataTypeString};

    DataTypePtr data_type_pos {new DataTypeInt64};

    while (!eof) {

        Block block = {{data_type_file_path, ICEBERG_FILE_PATH}, {data_type_pos, ICEBERG_ROW_POS}};

        size_t read_rows = 0;

        RETURN_IF_ERROR(orc_delete_reader.get_next_block(&block, &read_rows, &eof));

        _gen_position_delete_file_range(block, position_delete, read_rows, false);

    }

    return Status::OK();

}

// Directly read the deletion vector using the `content_offset` and

// `content_size_in_bytes` provided by FE in `delete_file_desc`.

// These two fields indicate the location of a blob in storage.

// Since the current format is `deletion-vector-v1`, which does not

// compress any blobs, we can temporarily skip parsing the Puffin footer.

Status IcebergTableReader::read_deletion_vector(const std::string& data_file_path,

                                                const TIcebergDeleteFileDesc& delete_file_desc) {

    Status create_status = Status::OK();

    SCOPED_TIMER(_iceberg_profile.delete_files_read_time);

    _iceberg_delete_rows = _kv_cache->get<DeleteRows>(data_file_path, [&]() -> DeleteRows* {

        auto* delete_rows = new DeleteRows;

        TFileRangeDesc delete_range;

        // must use __set() method to make sure __isset is true

        delete_range.__set_fs_name(_range.fs_name);

        delete_range.path = delete_file_desc.path;

        delete_range.start_offset = delete_file_desc.content_offset;

        delete_range.size = delete_file_desc.content_size_in_bytes;

        delete_range.file_size = -1;

        // We may consider caching the DeletionVectorReader when reading Puffin files,

        // where the underlying reader is an `InMemoryFileReader` and a single data file is

        // split into multiple splits. However, we need to ensure that the underlying

        // reader supports multi-threaded access.

        DeletionVectorReader dv_reader(_state, _profile, _params, delete_range, _io_ctx);

        create_status = dv_reader.open();

        if (!create_status.ok()) [[unlikely]] {

            return nullptr;

        }

        size_t buffer_size = delete_range.size;

        std::vector<char> buf(buffer_size);

        if (buffer_size < 12) [[unlikely]] {

            // Minimum size: 4 bytes length + 4 bytes magic + 4 bytes CRC32

            create_status = Status::DataQualityError("Deletion vector file size too small: {}",

                                                     buffer_size);

            return nullptr;

        }

        create_status = dv_reader.read_at(delete_range.start_offset, {buf.data(), buffer_size});

        if (!create_status) [[unlikely]] {

            return nullptr;

        }

        // The serialized blob contains:

        //

        // Combined length of the vector and magic bytes stored as 4 bytes, big-endian

        // A 4-byte magic sequence, D1 D3 39 64

        // The vector, serialized as described below

        // A CRC-32 checksum of the magic bytes and serialized vector as 4 bytes, big-endian

        auto total_length = BigEndian::Load32(buf.data());

        if (total_length + 8 != buffer_size) [[unlikely]] {

            create_status = Status::DataQualityError(

                    "Deletion vector length mismatch, expected: {}, actual: {}", total_length + 8,

                    buffer_size);

            return nullptr;

        }

        constexpr static char MAGIC_NUMBER[] = {'\xD1', '\xD3', '\x39', '\x64'};

        if (memcmp(buf.data() + sizeof(total_length), MAGIC_NUMBER, 4)) [[unlikely]] {

            create_status = Status::DataQualityError("Deletion vector magic number mismatch");

            return nullptr;

        }

        roaring::Roaring64Map bitmap;

        SCOPED_TIMER(_iceberg_profile.parse_delete_file_time);

        try {

            bitmap = roaring::Roaring64Map::readSafe(buf.data() + 8, buffer_size - 12);

        } catch (const std::runtime_error& e) {

            create_status = Status::DataQualityError("Decode roaring bitmap failed, {}", e.what());

            return nullptr;

        }

        // skip CRC-32 checksum

        delete_rows->reserve(bitmap.cardinality());

        for (auto it = bitmap.begin(); it != bitmap.end(); it++) {

            delete_rows->push_back(*it);

        }

        COUNTER_UPDATE(_iceberg_profile.num_delete_rows, delete_rows->size());

        return delete_rows;

    });

    RETURN_IF_ERROR(create_status);

    if (!_iceberg_delete_rows->empty()) [[likely]] {