ClickHouse/dbms/include/DB/Dictionaries/MySQLDictionarySource.h

#pragma once

#include <DB/Dictionaries/IDictionarySource.h>
#include <DB/Dictionaries/MySQLBlockInputStream.h>
#include <DB/Dictionaries/ExternalQueryBuilder.h>
#include <ext/range.hpp>
#include <mysqlxx/Pool.h>
#include <Poco/Util/AbstractConfiguration.h>


namespace DB
{


/// Allows loading dictionaries from a MySQL database
class MySQLDictionarySource final : public IDictionarySource
{
	static constexpr auto max_block_size = 8192;

public:
	MySQLDictionarySource(const DictionaryStructure & dict_struct_,
		const Poco::Util::AbstractConfiguration & config, const std::string & config_prefix,
		const Block & sample_block);

	/// copy-constructor is provided in order to support cloneability
	MySQLDictionarySource(const MySQLDictionarySource & other);
	
	BlockInputStreamPtr loadAll() override;

	BlockInputStreamPtr loadIds(const std::vector<std::uint64_t> & ids) override;

	BlockInputStreamPtr loadKeys(
		const ConstColumnPlainPtrs & key_columns, const std::vector<std::size_t> & requested_rows) override;

	bool isModified() const override;

	bool supportsSelectiveLoad() const override;

	DictionarySourcePtr clone() const override;

	std::string toString() const override;

private:
	Logger * log = &Logger::get("MySQLDictionarySource");

	static std::string quoteForLike(const std::string s);

	LocalDateTime getLastModification() const;

	const DictionaryStructure dict_struct;
	const std::string db;
	const std::string table;
	const std::string where;
	const bool dont_check_update_time;
	Block sample_block;
	mutable mysqlxx::PoolWithFailover pool;
	ExternalQueryBuilder query_builder;
	const std::string load_all_query;
	LocalDateTime last_modification;
};

}