ClickHouse/src/Storages/System/attachSystemTablesImpl.h
2020-12-11 02:58:11 +03:00

30 lines
1.1 KiB
C++

#pragma once
#include <Databases/IDatabase.h>
#include <Interpreters/DatabaseCatalog.h>
namespace DB
{
template<typename StorageT, typename... StorageArgs>
void attach(IDatabase & system_database, const String & table_name, StorageArgs && ... args)
{
if (system_database.getUUID() == UUIDHelpers::Nil)
{
/// Attach to Ordinary database
auto table_id = StorageID(DatabaseCatalog::SYSTEM_DATABASE, table_name);
system_database.attachTable(table_name, StorageT::create(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());
String path = "store/" + DatabaseCatalog::getPathForUUID(table_id.uuid);
system_database.attachTable(table_name, StorageT::create(table_id, std::forward<StorageArgs>(args)...), path);
}
}
}