Method execute

src/Interpreters/InterpreterRenameQuery.cpp:52–97

BlockIO InterpreterRenameQuery::execute()
{
    const auto & rename = query_ptr->as<const ASTRenameQuery &>();
    auto access_type = rename.database ? RenameType::RenameDatabase : RenameType::RenameTable;

    if (!rename.cluster.empty())
        return executeDDLQueryOnCluster(query_ptr, getContext(), getRequiredAccess(access_type));

    getContext()->checkAccess(getRequiredAccess(access_type));

    String path = getContext()->getPath();
    String current_database = getContext()->getCurrentDatabase();

    /** In case of error while renaming, it is possible that only part of tables was renamed
      *  or we will be in inconsistent state. (It is worth to be fixed.)
      */

    RenameDescriptions descriptions;
    descriptions.reserve(rename.elements.size());

    /// Don't allow to drop tables (that we are renaming); don't allow to create tables in places where tables will be renamed.
    TableGuards table_guards;

    for (const auto & elem : rename.elements)
    {
        descriptions.emplace_back(elem, current_database);
        const auto & description = descriptions.back();

        UniqueTableName from(description.from_database_name, description.from_table_name);
        UniqueTableName to(description.to_database_name, description.to_table_name);

        table_guards[from];
        table_guards[to];
    }

    auto & database_catalog = DatabaseCatalog::instance();

    /// Must do it in consistent order.
    for (auto & table_guard : table_guards)
        table_guard.second = database_catalog.getDDLGuard(table_guard.first.database_name, table_guard.first.table_name);

    if (rename.database)
        return executeToDatabase(rename, descriptions);
    else
        return executeToTables(rename, descriptions, table_guards);
}

BlockIO InterpreterRenameQuery::executeToTables(const ASTRenameQuery & rename, const RenameDescriptions & descriptions, TableGuards & ddl_guards)
{