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50 lines
1.5 KiB
C++
50 lines
1.5 KiB
C++
#pragma once
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#include <base/types.h>
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#include <DataTypes/IDataType.h>
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#include <Core/Block.h>
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namespace DB
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{
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class WriteBuffer;
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class CompressedWriteBuffer;
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struct IndexForNativeFormat;
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/** Serializes the stream of blocks in their native binary format (with names and column types).
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* Designed for communication between servers.
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*
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* A stream can be specified to write the index. The index contains offsets to each part of each column.
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* If an `append` is made to an existing file, and you need to write the index, then specify `initial_size_of_file`.
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*/
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class NativeWriter
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{
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public:
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/** If non-zero client_revision is specified, additional block information can be written.
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*/
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NativeWriter(
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WriteBuffer & ostr_, UInt64 client_revision_, const Block & header_, bool remove_low_cardinality_ = false,
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IndexForNativeFormat * index_ = nullptr, size_t initial_size_of_file_ = 0);
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Block getHeader() const { return header; }
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/// Returns the number of bytes written.
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size_t write(const Block & block);
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void flush();
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static String getContentType() { return "application/octet-stream"; }
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private:
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WriteBuffer & ostr;
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UInt64 client_revision;
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Block header;
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IndexForNativeFormat * index = nullptr;
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size_t initial_size_of_file; /// The initial size of the data file, if `append` done. Used for the index.
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/// If you need to write index, then `ostr` must be a CompressedWriteBuffer.
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CompressedWriteBuffer * ostr_concrete = nullptr;
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bool remove_low_cardinality;
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};
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}
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