mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-09-24 10:40:49 +00:00
131 lines
4.2 KiB
C++
131 lines
4.2 KiB
C++
#pragma once
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#include <DB/Dictionaries/IDictionarySource.h>
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#include <DB/Dictionaries/DictionaryStructure.h>
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#include <DB/Dictionaries/ExternalQueryBuilder.h>
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#include <DB/Client/ConnectionPool.h>
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#include <DB/DataStreams/RemoteBlockInputStream.h>
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#include <DB/Interpreters/executeQuery.h>
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#include <DB/Common/isLocalAddress.h>
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#include <ext/range.hpp>
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#include <Poco/Util/AbstractConfiguration.h>
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#include "writeParenthesisedString.h"
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int UNSUPPORTED_METHOD;
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}
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const auto max_connections = 16;
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/** Allows loading dictionaries from local or remote ClickHouse instance
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* @todo use ConnectionPoolWithFailover
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* @todo invent a way to keep track of source modifications
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*/
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class ClickHouseDictionarySource final : public IDictionarySource
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{
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public:
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ClickHouseDictionarySource(const DictionaryStructure & dict_struct_,
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const Poco::Util::AbstractConfiguration & config,
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const std::string & config_prefix,
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const Block & sample_block, Context & context)
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: dict_struct{dict_struct_},
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host{config.getString(config_prefix + ".host")},
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port(config.getInt(config_prefix + ".port")),
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user{config.getString(config_prefix + ".user", "")},
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password{config.getString(config_prefix + ".password", "")},
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db{config.getString(config_prefix + ".db", "")},
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table{config.getString(config_prefix + ".table")},
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where{config.getString(config_prefix + ".where", "")},
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query_builder{dict_struct, db, table, where},
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sample_block{sample_block}, context(context),
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is_local{isLocalAddress({ host, port })},
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pool{is_local ? nullptr : std::make_unique<ConnectionPool>(
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max_connections, host, port, db, user, password,
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"ClickHouseDictionarySource")
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},
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load_all_query{query_builder.composeLoadAllQuery()}
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{}
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/// copy-constructor is provided in order to support cloneability
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ClickHouseDictionarySource(const ClickHouseDictionarySource & other)
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: dict_struct{other.dict_struct},
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host{other.host}, port{other.port}, user{other.user}, password{other.password},
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db{other.db}, table{other.table},
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where{other.where},
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query_builder{dict_struct, db, table, where},
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sample_block{other.sample_block}, context(other.context),
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is_local{other.is_local},
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pool{is_local ? nullptr : std::make_unique<ConnectionPool>(
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max_connections, host, port, db, user, password,
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"ClickHouseDictionarySource")},
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load_all_query{other.load_all_query}
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{}
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BlockInputStreamPtr loadAll() override
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{
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/** Query to local ClickHouse is marked internal in order to avoid
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* the necessity of holding process_list_element shared pointer.
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*/
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if (is_local)
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return executeQuery(load_all_query, context, true).in;
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return std::make_shared<RemoteBlockInputStream>(pool.get(), load_all_query, nullptr);
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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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return createStreamForSelectiveLoad(
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query_builder.composeLoadIdsQuery(ids));
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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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return createStreamForSelectiveLoad(
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query_builder.composeLoadKeysQuery(
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key_columns, requested_rows, ExternalQueryBuilder::IN_WITH_TUPLES));
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}
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bool isModified() const override { return true; }
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bool supportsSelectiveLoad() const override { return true; }
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DictionarySourcePtr clone() const override { return std::make_unique<ClickHouseDictionarySource>(*this); }
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std::string toString() const override
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{
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return "ClickHouse: " + db + '.' + table + (where.empty() ? "" : ", where: " + where);
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}
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private:
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BlockInputStreamPtr createStreamForSelectiveLoad(const std::string query)
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{
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if (is_local)
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return executeQuery(query, context, true).in;
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return std::make_shared<RemoteBlockInputStream>(pool.get(), query, nullptr);
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}
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const DictionaryStructure dict_struct;
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const std::string host;
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const UInt16 port;
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const std::string user;
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const std::string password;
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const std::string db;
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const std::string table;
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const std::string where;
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ExternalQueryBuilder query_builder;
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Block sample_block;
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Context & context;
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const bool is_local;
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std::unique_ptr<ConnectionPool> pool;
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const std::string load_all_query;
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};
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}
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