ClickHouse/src/TableFunctions/TableFunctionMySQL.cpp

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#if !defined(ARCADIA_BUILD)
#include "config_core.h"
#endif
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#if USE_MYSQL
#include <Core/Defines.h>
#include <Databases/MySQL/FetchTablesColumnsList.h>
#include <DataTypes/DataTypeString.h>
#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/convertMySQLDataType.h>
#include <Formats/MySQLBlockInputStream.h>
#include <IO/Operators.h>
#include <Interpreters/Context.h>
#include <Interpreters/evaluateConstantExpression.h>
#include <Parsers/ASTFunction.h>
#include <Parsers/ASTLiteral.h>
#include <Storages/StorageMySQL.h>
#include <TableFunctions/ITableFunction.h>
#include <TableFunctions/TableFunctionFactory.h>
#include <TableFunctions/TableFunctionMySQL.h>
#include <Common/Exception.h>
#include <Common/parseAddress.h>
#include <Common/quoteString.h>
#include "registerTableFunctions.h"
#include <Databases/MySQL/DatabaseConnectionMySQL.h> // for fetchTablesColumnsList
#include <Common/parseRemoteDescription.h>
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namespace DB
{
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namespace ErrorCodes
{
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extern const int LOGICAL_ERROR;
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
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extern const int BAD_ARGUMENTS;
extern const int UNKNOWN_TABLE;
}
void TableFunctionMySQL::parseArguments(const ASTPtr & ast_function, const Context & context)
{
const auto & args_func = ast_function->as<ASTFunction &>();
if (!args_func.arguments)
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throw Exception("Table function 'mysql' must have arguments.", ErrorCodes::LOGICAL_ERROR);
ASTs & args = args_func.arguments->children;
if (args.size() < 5 || args.size() > 7)
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throw Exception("Table function 'mysql' requires 5-7 parameters: MySQL('host:port', database, table, 'user', 'password'[, replace_query, 'on_duplicate_clause']).",
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
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for (auto & arg : args)
arg = evaluateConstantExpressionOrIdentifierAsLiteral(arg, context);
String host_port = args[0]->as<ASTLiteral &>().value.safeGet<String>();
remote_database_name = args[1]->as<ASTLiteral &>().value.safeGet<String>();
remote_table_name = args[2]->as<ASTLiteral &>().value.safeGet<String>();
user_name = args[3]->as<ASTLiteral &>().value.safeGet<String>();
password = args[4]->as<ASTLiteral &>().value.safeGet<String>();
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/// Split into replicas if needed. 3306 is the default MySQL port number
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size_t max_addresses = context.getSettingsRef().glob_expansion_max_elements;
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auto addresses = parseRemoteDescriptionForExternalDatabase(host_port, max_addresses, 3306);
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pool.emplace(remote_database_name, addresses, user_name, password);
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if (args.size() >= 6)
replace_query = args[5]->as<ASTLiteral &>().value.safeGet<UInt64>() > 0;
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if (args.size() == 7)
on_duplicate_clause = args[6]->as<ASTLiteral &>().value.safeGet<String>();
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if (replace_query && !on_duplicate_clause.empty())
throw Exception(
"Only one of 'replace_query' and 'on_duplicate_clause' can be specified, or none of them",
ErrorCodes::BAD_ARGUMENTS);
}
ColumnsDescription TableFunctionMySQL::getActualTableStructure(const Context & context) const
{
const auto & settings = context.getSettingsRef();
const auto tables_and_columns = fetchTablesColumnsList(*pool, remote_database_name, {remote_table_name}, settings.external_table_functions_use_nulls, settings.mysql_datatypes_support_level);
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const auto columns = tables_and_columns.find(remote_table_name);
if (columns == tables_and_columns.end())
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throw Exception("MySQL table " + backQuoteIfNeed(remote_database_name) + "." + backQuoteIfNeed(remote_table_name) + " doesn't exist.", ErrorCodes::UNKNOWN_TABLE);
return ColumnsDescription{columns->second};
}
StoragePtr TableFunctionMySQL::executeImpl(const ASTPtr & /*ast_function*/, const Context & context, const std::string & table_name, ColumnsDescription /*cached_columns*/) const
{
auto columns = getActualTableStructure(context);
auto res = StorageMySQL::create(
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StorageID(getDatabaseName(), table_name),
std::move(*pool),
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remote_database_name,
remote_table_name,
replace_query,
on_duplicate_clause,
columns,
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ConstraintsDescription{},
context);
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pool.reset();
res->startup();
return res;
}
void registerTableFunctionMySQL(TableFunctionFactory & factory)
{
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factory.registerFunction<TableFunctionMySQL>();
}
}
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#endif