eldenmoon commented on code in PR #65561: URL: https://github.com/apache/doris/pull/65561#discussion_r3575629102
########## be/src/core/column/column_variant_v2.h: ########## @@ -0,0 +1,228 @@ +// 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. + +#pragma once + +#include <memory> +#include <span> +#include <string> + +#include "core/column/column.h" +#include "core/custom_allocator.h" +#include "core/data_type/data_type.h" +#include "util/variant/variant_field.h" + +namespace doris { + +class VariantEncodedBlockView; + +// ColumnVariantV2 stores a whole column in exactly one state: encoded Variant bytes or one nullable +// typed scalar column. Mixed operations materialize the typed state as encoded bytes atomically. +class ColumnVariantV2 final : public COWHelper<IColumn, ColumnVariantV2> { +public: + struct TypedEncodingStats { + size_t largeint_string_fallback_rows = 0; + size_t decimal256_string_fallback_rows = 0; + size_t ip_string_fallback_rows = 0; + }; + + struct EncodedDataView { + StringRef metadata_bytes; + std::span<const uint32_t> metadata_offsets; + std::span<const uint32_t> meta_ids; + StringRef value_bytes; + std::span<const uint32_t> value_offsets; + }; + + // Borrowed immutable adapter for whole-column E/T readers. The source column owns every + // referenced column, type, and byte; any structural mutation invalidates this view. Encoded + // metadata is validated lazily once per dense id, and values are required to occupy their exact + // row boundary. The cache is call-local and uses tracked storage. + class ReadView { + public: + bool is_typed() const noexcept { return _typed_state; } + size_t size() const noexcept; + size_t metadata_count() const noexcept; + uint32_t metadata_id_at(size_t row) const; + VariantMetadataRef metadata_at(uint32_t id) const; + VariantValueRef value_at(size_t row) const; + const IColumn& typed_column() const; + const DataTypePtr& typed_type() const; + + private: + friend class ColumnVariantV2; + ReadView(const IColumn* metadatas, const IColumn* metadata_ids, const IColumn* values); + ReadView(const IColumn* typed, const DataTypePtr* typed_type); + + bool _typed_state = false; + const IColumn* _metadatas = nullptr; + const IColumn* _metadata_ids = nullptr; + const IColumn* _values = nullptr; + const IColumn* _typed = nullptr; + const DataTypePtr* _typed_type = nullptr; + mutable DorisVector<uint8_t> _validated_metadata; + }; + +#ifdef BE_TEST + // Narrow unit-test seam for deterministic hash-collision and lazy-index coverage. + struct TestAccess { + static uint32_t find_or_insert_metadata(ColumnVariantV2& column, StringRef metadata) { + return column._find_or_insert_metadata(metadata); + } + + static uint32_t find_or_insert_metadata(ColumnVariantV2& column, StringRef metadata, + uint64_t hash) { + return column._find_or_insert_metadata(metadata, hash); + } + + static void reset_metadata_index(ColumnVariantV2& column); + + static void replace_encoded_subcolumn(ColumnVariantV2& column, size_t index, + ColumnPtr replacement); + }; +#endif + + ~ColumnVariantV2() override; + + // The only typed-state construction points. The input must be an exact, non-Const + // ColumnNullable whose nested column matches the non-nullable supported scalar type. + static MutablePtr create_typed_from_scan(ColumnPtr column, DataTypePtr scalar_type); + static MutablePtr create_typed_from_element_at(ColumnPtr column, DataTypePtr scalar_type); + static MutablePtr create_typed_from_cast(ColumnPtr column, DataTypePtr scalar_type); + // The exchange decoder is the fourth and final approved typed-state construction point. + static MutablePtr create_typed_from_exchange(ColumnPtr column, DataTypePtr scalar_type); + + bool is_typed() const noexcept { return _typed != nullptr; } + const IColumn& typed_column() const; + const DataTypePtr& typed_type() const; + TypedEncodingStats ensure_encoded(); + ReadView read_view() const; + + std::string get_name() const override; + size_t size() const override; + size_t byte_size() const override; + size_t allocated_bytes() const override; + bool has_enough_capacity(const IColumn& src) const override; + bool is_variable_length() const override { return true; } + bool structure_equals(const IColumn& rhs) const override; + + void sanity_check() const override; + void for_each_subcolumn(ColumnCallback callback) const override; + void clear() override; + void finalize() override {} + + // Cold compatibility adapter for one already-validated VariantField. Batch producers use the + // bulk/remap paths added by T2.2 instead of calling this once per row. + void insert_variant_field(const VariantField& field); + + // Validates the borrowed buffer/offset/id structure, then appends codec-validated encoded rows + // without retaining any input pointer. Offsets use the ColumnString uint32 domain and start at + // zero. Empty meta_ids is the compact representation for a batch whose rows all use its single + // metadata blob. Input buffers must not alias this column; use insert_range_from for that case. + void insert_encoded_rows(const EncodedDataView& data); + + // Direct shared-metadata codec adapter. The block already uses ColumnString-compatible uint32 + // offsets, so this path borrows its buffers without an O(rows) offset conversion. + void insert_encoded_block(VariantEncodedBlockView block); + + // The returned view borrows this column's metadata and value buffers. Any structural mutation, + // including insert, clear, COW mutation, or future row transformations, may invalidate it. + VariantValueRef get_value_ref(size_t row) const; + + Field operator[](size_t row) const override; + void get(size_t row, Field& result) const override; + void insert(const Field& field) override; + void insert_default() override; + void insert_many_defaults(size_t length) override; + + void insert_from(const IColumn& src, size_t row) override; + void insert_range_from(const IColumn& src, size_t start, size_t length) override; + void insert_indices_from(const IColumn& src, const uint32_t* indices_begin, + const uint32_t* indices_end) override; + void pop_back(size_t length) override; + + StringRef get_data_at(size_t row) const override; + void insert_data(const char* pos, size_t length) override; + StringRef serialize_value_into_arena(size_t row, Arena& arena, + const char*& begin) const override; + const char* deserialize_and_insert_from_arena(const char* pos) override; + size_t serialize_size_at(size_t row) const override; + size_t serialize_impl(char* pos, size_t row) const override; + size_t deserialize_impl(const char* pos) override; + size_t get_max_row_byte_size() const override; + void serialize(StringRef* keys, size_t num_rows) const override; + void deserialize(StringRef* keys, size_t num_rows) override; + + void update_hash_with_value(size_t row, SipHash& hash) const override; + void update_hashes_with_value(uint64_t* __restrict hashes, + const uint8_t* __restrict null_data) const override; + void update_xxHash_with_value(size_t start, size_t end, uint64_t& hash, + const uint8_t* __restrict null_data) const override; + void update_crcs_with_value(uint32_t* __restrict hashes, PrimitiveType type, uint32_t rows, + uint32_t offset, + const uint8_t* __restrict null_data) const override; + void update_crc_with_value(size_t start, size_t end, uint32_t& hash, + const uint8_t* __restrict null_data) const override; + void update_crc32c_batch(uint32_t* __restrict hashes, + const uint8_t* __restrict null_map) const override; + void update_crc32c_single(size_t start, size_t end, uint32_t& hash, + const uint8_t* __restrict null_map) const override; + void replace_column_null_data(const uint8_t* __restrict null_map) override; + + ColumnPtr filter(const Filter& filter, ssize_t result_size_hint) const override; + size_t filter(const Filter& filter) override; + MutableColumnPtr permute(const Permutation& permutation, size_t limit) const override; + MutableColumnPtr clone_resized(size_t size) const override; + void resize(size_t size) override; + + int compare_at(size_t lhs, size_t rhs, const IColumn& rhs_column, + int nan_direction_hint) const override; + void get_permutation(bool reverse, size_t limit, int nan_direction_hint, HybridSorter& sorter, + Permutation& result) const override; + void replace_column_data(const IColumn& rhs, size_t row, size_t self_row = 0) override; + +private: + friend class COWHelper<IColumn, ColumnVariantV2>; + + struct MetaDictIndex; + + ColumnVariantV2(); + ColumnVariantV2(const ColumnVariantV2& other); + + uint32_t _find_or_insert_metadata(StringRef metadata); + uint32_t _find_or_insert_metadata(StringRef metadata, uint64_t hash); + void _adopt_state_from(ColumnVariantV2& replacement); + void _detach_metadata_for_write(); + void _rollback_metadata(size_t old_count, IColumn::Ptr original_metadata); + void _check_invariants() const; + void mutate_subcolumns() override; + + // Encoded state: each row owns a value and references one deduplicated metadata blob. + IColumn::WrappedPtr _metadatas; + IColumn::WrappedPtr _meta_ids; Review Comment: _meta_ids 引入， 为了维护这个id， 是否会导致性能问题,如果有性能退化， 需要去掉 -- This is an automated message from the Apache Git Service. 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