ClickHouse/dbms/src/Storages/StorageMySQL.cpp

95 lines
3.0 KiB
C++

#include <Storages/StorageMySQL.h>
#if USE_MYSQL
#include <Storages/StorageFactory.h>
#include <Storages/transformQueryForExternalDatabase.h>
#include <Dictionaries/MySQLBlockInputStream.h>
#include <Interpreters/evaluateConstantExpression.h>
#include <Common/parseAddress.h>
#include <Parsers/ASTLiteral.h>
namespace DB
{
namespace ErrorCodes
{
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
}
StorageMySQL::StorageMySQL(
const std::string & name,
mysqlxx::Pool && pool,
const std::string & remote_database_name,
const std::string & remote_table_name,
const NamesAndTypesList & columns)
: name(name)
, remote_database_name(remote_database_name)
, remote_table_name(remote_table_name)
, columns(columns)
, pool(std::move(pool))
{
}
BlockInputStreams StorageMySQL::read(
const Names & column_names,
const SelectQueryInfo & query_info,
const Context & context,
QueryProcessingStage::Enum & processed_stage,
size_t max_block_size,
unsigned)
{
check(column_names);
processed_stage = QueryProcessingStage::FetchColumns;
String query = transformQueryForExternalDatabase(*query_info.query, columns, remote_database_name, remote_table_name, context);
Block sample_block;
for (const String & name : column_names)
{
auto column_data = getColumn(name);
sample_block.insert({ column_data.type, column_data.name });
}
return { std::make_shared<MySQLBlockInputStream>(pool.Get(), query, sample_block, max_block_size) };
}
void registerStorageMySQL(StorageFactory & factory)
{
factory.registerStorage("MySQL", [](const StorageFactory::Arguments & args)
{
ASTs & engine_args = args.engine_args;
if (engine_args.size() != 5)
throw Exception(
"Storage MySQL requires exactly 5 parameters: MySQL('host:port', database, table, 'user', 'password').",
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
for (size_t i = 0; i < 5; ++i)
engine_args[i] = evaluateConstantExpressionOrIdentifierAsLiteral(engine_args[i], args.local_context);
/// 3306 is the default MySQL port.
auto parsed_host_port = parseAddress(static_cast<const ASTLiteral &>(*engine_args[0]).value.safeGet<String>(), 3306);
const String & remote_database = static_cast<const ASTLiteral &>(*engine_args[1]).value.safeGet<String>();
const String & remote_table = static_cast<const ASTLiteral &>(*engine_args[2]).value.safeGet<String>();
const String & username = static_cast<const ASTLiteral &>(*engine_args[3]).value.safeGet<String>();
const String & password = static_cast<const ASTLiteral &>(*engine_args[4]).value.safeGet<String>();
mysqlxx::Pool pool(remote_database, parsed_host_port.first, username, password, parsed_host_port.second);
return StorageMySQL::create(
args.table_name,
std::move(pool),
remote_database,
remote_table,
args.columns);
});
}
}
#endif