ClickHouse/dbms/src/Dictionaries/ClickHouseDictionarySource.cpp

#include <Dictionaries/ClickHouseDictionarySource.h>
#include <Dictionaries/ExternalQueryBuilder.h>
#include <Dictionaries/writeParenthesisedString.h>
#include <Client/ConnectionPool.h>
#include <DataStreams/RemoteBlockInputStream.h>
#include <Interpreters/executeQuery.h>
#include <Common/isLocalAddress.h>
#include <memory>
#include <ext/range.hpp>


namespace DB
{

namespace ErrorCodes
{
    extern const int UNSUPPORTED_METHOD;
}


static const size_t max_connections = 16;


ClickHouseDictionarySource::ClickHouseDictionarySource(const DictionaryStructure & dict_struct_,
    const Poco::Util::AbstractConfiguration & config,
    const std::string & config_prefix,
    const Block & sample_block, Context & context)
    : dict_struct{dict_struct_},
        host{config.getString(config_prefix + ".host")},
        port(config.getInt(config_prefix + ".port")),
        user{config.getString(config_prefix + ".user", "")},
        password{config.getString(config_prefix + ".password", "")},
        db{config.getString(config_prefix + ".db", "")},
        table{config.getString(config_prefix + ".table")},
        where{config.getString(config_prefix + ".where", "")},
        query_builder{dict_struct, db, table, where, ExternalQueryBuilder::Backticks},
        sample_block{sample_block}, context(context),
        is_local{isLocalAddress({ host, port })},
        pool{is_local ? nullptr : std::make_shared<ConnectionPool>(
            max_connections, host, port, db, user, password,
            "ClickHouseDictionarySource")
        },
        load_all_query{query_builder.composeLoadAllQuery()}
{}


ClickHouseDictionarySource::ClickHouseDictionarySource(const ClickHouseDictionarySource & other)
    : dict_struct{other.dict_struct},
        host{other.host}, port{other.port}, user{other.user}, password{other.password},
        db{other.db}, table{other.table},
        where{other.where},
        query_builder{dict_struct, db, table, where, ExternalQueryBuilder::Backticks},
        sample_block{other.sample_block}, context(other.context),
        is_local{other.is_local},
        pool{is_local ? nullptr : std::make_shared<ConnectionPool>(
            max_connections, host, port, db, user, password,
            "ClickHouseDictionarySource")},
        load_all_query{other.load_all_query}
{}


BlockInputStreamPtr ClickHouseDictionarySource::loadAll()
{
    /** Query to local ClickHouse is marked internal in order to avoid
      *    the necessity of holding process_list_element shared pointer.
      */
    if (is_local)
        return executeQuery(load_all_query, context, true).in;
    return std::make_shared<RemoteBlockInputStream>(pool, load_all_query, nullptr);
}


BlockInputStreamPtr ClickHouseDictionarySource::loadIds(const std::vector<UInt64> & ids)
{
    return createStreamForSelectiveLoad(
        query_builder.composeLoadIdsQuery(ids));
}


BlockInputStreamPtr ClickHouseDictionarySource::loadKeys(
    const ConstColumnPlainPtrs & key_columns, const std::vector<std::size_t> & requested_rows)
{
    return createStreamForSelectiveLoad(
        query_builder.composeLoadKeysQuery(
            key_columns, requested_rows, ExternalQueryBuilder::IN_WITH_TUPLES));
}


std::string ClickHouseDictionarySource::toString() const
{
    return "ClickHouse: " + db + '.' + table + (where.empty() ? "" : ", where: " + where);
}


BlockInputStreamPtr ClickHouseDictionarySource::createStreamForSelectiveLoad(const std::string query)
{
    if (is_local)
        return executeQuery(query, context, true).in;
    return std::make_shared<RemoteBlockInputStream>(pool, query, nullptr);
}

}