be/src/exec/exchange/exchange_writer.h

// 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 <cstdint>

#include "exec/exchange/vdata_stream_sender.h"
#include "exec/partitioner/partitioner.h"

namespace doris {
class RuntimeState;
class Status;
class Block;
class Channel;
class PartitionerBase;
class TabletSinkHashPartitioner;

class ExchangeSinkLocalState;

class ExchangeWriterBase {
public:
    using HashValType = PartitionerBase::HashValType;
    ExchangeWriterBase(ExchangeSinkLocalState& local_state);

    virtual Status write(RuntimeState* state, Block* block, bool eos) = 0;

    virtual ~ExchangeWriterBase() = default;

protected:
    template <typename ChannelPtrType>
    Status _handle_eof_channel(RuntimeState* state, ChannelPtrType channel, Status st) const;
    Status _add_rows_impl(RuntimeState* state, std::vector<std::shared_ptr<Channel>>& channels,
                          size_t channel_count, Block* block, bool eos);

    // myself as a visitor of local state
    ExchangeSinkLocalState& _local_state;
    PartitionerBase* _partitioner;

    // _origin_row_idx[i]: row id in original block for the i-th's data we send.
    PaddedPODArray<uint32_t> _origin_row_idx;
    // _channel_rows_histogram[i]: number of rows for channel i in current batch
    PaddedPODArray<uint32_t> _channel_rows_histogram;
    // _channel_start_offsets[i]: the start offset of channel i in _row_idx
    // its value equals to prefix sum of _channel_rows_histogram
    // after calculation, it will be end offset for channel i.
    PaddedPODArray<uint32_t> _channel_pos_offsets;
};

class ExchangeTrivialWriter final : public ExchangeWriterBase {
public:
    ExchangeTrivialWriter(ExchangeSinkLocalState& local_state) : ExchangeWriterBase(local_state) {}

    Status write(RuntimeState* state, Block* block, bool eos) override;

private:
    Status _channel_add_rows(RuntimeState* state, std::vector<std::shared_ptr<Channel>>& channels,
                             size_t channel_count, const std::vector<HashValType>& channel_ids,
                             size_t rows, Block* block, bool eos);
};

// maybe auto partition
class ExchangeOlapWriter final : public ExchangeWriterBase {
public:
    ExchangeOlapWriter(ExchangeSinkLocalState& local_state) : ExchangeWriterBase(local_state) {}

    Status write(RuntimeState* state, Block* block, bool eos) override;

private:
    Status _write_impl(RuntimeState* state, Block* block, bool eos = false);
    Status _channel_add_rows(RuntimeState* state, std::vector<std::shared_ptr<Channel>>& channels,
                             size_t channel_count, const std::vector<HashValType>& channel_ids,
                             size_t rows, Block* block, bool eos, HashValType invalid_val);
};
} // namespace doris