mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-18 21:51:57 +00:00
96 lines
3.2 KiB
C++
96 lines
3.2 KiB
C++
|
#pragma once
|
|||
|
|
|
|||
|
|
#include <DB/Common/OptimizedRegularExpression.h>
|
|||
|
|
|
|||
|
|
#include <DB/Storages/StorageFactory.h>
|
|||
|
|
#include <DB/Storages/StorageMerge.h>
|
|||
|
|
#include <DB/Parsers/ASTExpressionList.h>
|
|||
|
|
#include <DB/Parsers/ASTIdentifier.h>
|
|||
|
|
#include <DB/Parsers/ASTLiteral.h>
|
|||
|
|
#include <DB/TableFunctions/ITableFunction.h>
|
|||
|
|
#include <DB/Interpreters/reinterpretAsIdentifier.h>
|
|||
|
|
#include <DB/Databases/IDatabase.h>
|
|||
|
|
|
|||
|
|
|
|||
|
|
namespace DB
|
|||
|
|
{
|
|||
|
|
|
|||
|
|
namespace ErrorCodes
|
|||
|
|
{
|
|||
|
|
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
|
|||
|
|
extern const int UNKNOWN_TABLE;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
|
|||
|
|
/*
|
|||
|
|
* merge(db_name, tables_regexp)- создаёт временный StorageMerge.
|
|||
|
|
* Cтруктура таблицы берётся из первой попавшейся таблицы, подходящей под регексп.
|
|||
|
|
* Если такой таблицы нет - кидается исключение.
|
|||
|
|
*/
|
|||
|
|
|
|||
|
|
class TableFunctionMerge: public ITableFunction
|
|||
|
|
{
|
|||
|
|
public:
|
|||
|
|
std::string getName() const override { return "merge"; }
|
|||
|
|
|
|||
|
|
StoragePtr execute(ASTPtr ast_function, Context & context) const override
|
|||
|
|
{
|
|||
|
|
ASTs & args_func = typeid_cast<ASTFunction &>(*ast_function).children;
|
|||
|
|
|
|||
|
|
if (args_func.size() != 1)
|
|||
|
|
throw Exception("Storage Merge requires exactly 2 parameters"
|
|||
|
|
" - name of source database and regexp for table names.",
|
|||
|
|
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
|
|||
|
|
|
|||
|
|
ASTs & args = typeid_cast<ASTExpressionList &>(*args_func.at(0)).children;
|
|||
|
|
|
|||
|
|
if (args.size() != 2)
|
|||
|
|
throw Exception("Storage Merge requires exactly 2 parameters"
|
|||
|
|
" - name of source database and regexp for table names.",
|
|||
|
|
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
|
|||
|
|
|
|||
|
|
String source_database = reinterpretAsIdentifier(args[0], context).name;
|
|||
|
|
String table_name_regexp = safeGet<const String &>(typeid_cast<ASTLiteral &>(*args[1]).value);
|
|||
|
|
|
|||
|
|
/// В InterpreterSelectQuery будет создан ExpressionAnalzyer, который при обработке запроса наткнется на этот Identifier.
|
|||
|
|
/// Нам необходимо его пометить как имя базы данных, поскольку по умолчанию стоит значение column
|
|||
|
|
typeid_cast<ASTIdentifier &>(*args[0]).kind = ASTIdentifier::Database;
|
|||
|
|
|
|||
|
|
return StorageMerge::create(getName(), chooseColumns(source_database, table_name_regexp, context),
|
|||
|
|
source_database, table_name_regexp, context);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
private:
|
|||
|
|
NamesAndTypesListPtr chooseColumns(const String & source_database, const String & table_name_regexp_, const Context & context) const
|
|||
|
|
{
|
|||
|
|
OptimizedRegularExpression table_name_regexp(table_name_regexp_);
|
|||
|
|
|
|||
|
|
StoragePtr any_table;
|
|||
|
|
|
|||
|
|
{
|
|||
|
|
auto database = context.getDatabase(source_database);
|
|||
|
|
auto iterator = database->getIterator();
|
|||
|
|
|
|||
|
|
while (iterator->isValid())
|
|||
|
|
{
|
|||
|
|
if (table_name_regexp.match(iterator->name()))
|
|||
|
|
{
|
|||
|
|
any_table = iterator->table();
|
|||
|
|
break;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
iterator->next();
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
if (!any_table)
|
|||
|
|
throw Exception("Error while executing table function merge. In database " + source_database + " no one matches regular expression: " + table_name_regexp_, ErrorCodes::UNKNOWN_TABLE);
|
|||
|
|
|
|||
|
|
auto table_lock = any_table->lockStructure(false);
|
|||
|
|
return new NamesAndTypesList(any_table->getColumnsList());
|
|||
|
|
}
|
|||
|
|
};
|
|||
|
|
|
|||
|
|
|
|||
|
|
}
|