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0fd1fc9cdc
Requires a way of deallocating keys in memory Arena (a new type of arena, actually), MySQLDictionarySource not yet capable of requesting complex keys.
71 lines
2.2 KiB
C++
71 lines
2.2 KiB
C++
#pragma once
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#include <DB/Interpreters/Context.h>
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#include <DB/Dictionaries/DictionaryStructure.h>
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#include <DB/Dictionaries/IDictionarySource.h>
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#include <DB/Dictionaries/OwningBufferBlockInputStream.h>
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#include <DB/IO/ReadBufferFromFile.h>
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#include <DB/DataStreams/FormatFactory.h>
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#include <Poco/Timestamp.h>
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#include <Poco/File.h>
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namespace DB
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{
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/// Allows loading dictionaries from a file with given format, does not support "random access"
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class FileDictionarySource final : public IDictionarySource
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{
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static const auto max_block_size = 8192;
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public:
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FileDictionarySource(const std::string & filename, const std::string & format, Block & sample_block,
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const Context & context)
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: filename{filename}, format{format}, sample_block{sample_block}, context(context)
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{}
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FileDictionarySource(const FileDictionarySource & other)
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: filename{other.filename}, format{other.format},
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sample_block{other.sample_block}, context(other.context),
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last_modification{other.last_modification}
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{}
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BlockInputStreamPtr loadAll() override
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{
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auto in_ptr = std::make_unique<ReadBufferFromFile>(filename);
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auto stream = context.getFormatFactory().getInput(
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format, *in_ptr, sample_block, max_block_size);
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last_modification = getLastModification();
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return new OwningBufferBlockInputStream{stream, std::move(in_ptr)};
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}
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BlockInputStreamPtr loadIds(const std::vector<std::uint64_t> & ids) override
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{
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throw Exception{"Method unsupported", ErrorCodes::NOT_IMPLEMENTED};
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}
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BlockInputStreamPtr loadKeys(
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const ConstColumnPlainPtrs & key_columns, const std::vector<std::size_t> & requested_rows) override
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{
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throw Exception{"Method unsupported", ErrorCodes::NOT_IMPLEMENTED};
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}
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bool isModified() const override { return getLastModification() > last_modification; }
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bool supportsSelectiveLoad() const override { return false; }
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DictionarySourcePtr clone() const override { return std::make_unique<FileDictionarySource>(*this); }
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std::string toString() const override { return "File: " + filename + ' ' + format; }
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private:
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Poco::Timestamp getLastModification() const { return Poco::File{filename}.getLastModified(); }
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const std::string filename;
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const std::string format;
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Block sample_block;
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const Context & context;
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Poco::Timestamp last_modification;
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};
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}
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