Function convertOrdinaryDatabaseToAtomic

src/Interpreters/loadMetadata.cpp:375–483

}

static void convertOrdinaryDatabaseToAtomic(LoggerPtr log, ContextMutablePtr context, const DatabasePtr & database,
                                            const String & name, const String tmp_name)
{
    /// It's kind of C++ script that creates temporary database with Atomic engine,
    /// moves all tables to it, drops old database and then renames new one to old name.

    String name_quoted = backQuoteIfNeed(name);
    String tmp_name_quoted = backQuoteIfNeed(tmp_name);

    LOG_INFO(log, "Will convert database {} from Ordinary to Atomic", name_quoted);

    {
        auto create_database_query_context = Context::createCopy(context);
        create_database_query_context->makeQueryContext();
        create_database_query_context->setCurrentQueryId("");

        QueryScope query_scope;
        if (!CurrentThread::getGroup())
            query_scope = QueryScope::create(create_database_query_context);

        String create_database_query = fmt::format("CREATE DATABASE IF NOT EXISTS {}", tmp_name_quoted);

        auto res = executeQuery(create_database_query, std::move(create_database_query_context), QueryFlags{ .internal = true }).second;
        executeTrivialBlockIO(res, context);
    }

    auto tmp_database = DatabaseCatalog::instance().getDatabase(tmp_name);
    chassert(tmp_database->getEngineName() == "Atomic");

    size_t num_tables = 0;
    std::unordered_set<String> inner_mv_tables;
    for (auto iterator = database->getTablesIterator(context); iterator->isValid(); iterator->next())
    {
        ++num_tables;
        auto id = iterator->table()->getStorageID();
        id.database_name = tmp_name;
        /// We need some uuid for checkTableCanBeRenamed
        id.uuid = UUIDHelpers::generateV4();
        iterator->table()->checkTableCanBeRenamed(id);
        if (const auto * mv = dynamic_cast<const StorageMaterializedView *>(iterator->table().get()))
        {
            /// We should not rename inner tables of MVs, because MVs are responsible for renaming it...
            if (mv->hasInnerTable())
                inner_mv_tables.emplace(mv->getTargetTable()->getStorageID().table_name);
        }
    }

    LOG_INFO(log, "Will move {} tables to {} (including {} inner tables of MVs)", num_tables, tmp_name_quoted, inner_mv_tables.size());

    for (auto iterator = database->getTablesIterator(context); iterator->isValid(); iterator->next())
    {
        auto id = iterator->table()->getStorageID();
        if (inner_mv_tables.contains(id.table_name))
        {
            LOG_DEBUG(log, "Do not rename {}, because it will be renamed together with MV", id.getNameForLogs());
            continue;
        }