ClickHouse/src/Storages/System/attachSystemTablesImpl.h
Alexander Tokmakov ed8341025b make code less bad
2022-06-22 18:31:42 +02:00

32 lines
1.3 KiB
C++

#pragma once
#include <Databases/IDatabase.h>
#include <Interpreters/DatabaseCatalog.h>
namespace DB
{
template<typename StorageT, typename... StorageArgs>
void attach(ContextPtr context, IDatabase & system_database, const String & table_name, StorageArgs && ... args)
{
assert(system_database.getDatabaseName() == DatabaseCatalog::SYSTEM_DATABASE);
if (system_database.getUUID() == UUIDHelpers::Nil)
{
/// Attach to Ordinary database.
auto table_id = StorageID(DatabaseCatalog::SYSTEM_DATABASE, table_name);
system_database.attachTable(context, table_name, std::make_shared<StorageT>(table_id, std::forward<StorageArgs>(args)...));
}
else
{
/// Attach to Atomic database.
/// NOTE: UUIDs are not persistent, but it's ok since no data are stored on disk for these storages
/// and path is actually not used
auto table_id = StorageID(DatabaseCatalog::SYSTEM_DATABASE, table_name, UUIDHelpers::generateV4());
DatabaseCatalog::instance().addUUIDMapping(table_id.uuid);
String path = "store/" + DatabaseCatalog::getPathForUUID(table_id.uuid);
system_database.attachTable(context, table_name, std::make_shared<StorageT>(table_id, std::forward<StorageArgs>(args)...), path);
}
}
}