**Use case**

If FixedString is used with more than 256 bytes in size, it is suspicious and most likely indicates misusage.
Forbid this by default and add a setting to override it; ATTACH queries should allow creating tables nevertheless.

See also: `allow_suspicious_low_cardinality_types`.

bool sanity_check_compression_codecs = !attach && !context_->getSettingsRef().allow_suspicious_codecs;
    bool allow_experimental_codecs = attach || context_->getSettingsRef().allow_experimental_codecs;
    ColumnsDescription res;
    auto name_type_it = column_names_and_types.begin();
    for (auto ast_it = columns_ast.children.begin(); ast_it != columns_ast.children.end(); ++ast_it, ++name_type_it)
    {
        ColumnDescription column;
        auto & col_decl = (*ast_it)->as<ASTColumnDeclaration &>();
        column.name = col_decl.name;
        
        if (col_decl.default_specifier == "AUTO_INCREMENT"
            && !context_->getSettingsRef().compatibility_ignore_auto_increment_in_create_table)
        {
            throw Exception(
                "AUTO_INCREMENT is not supported. To ignore the keyword in column declaration, set "
                "`compatibility_ignore_auto_increment_in_create_table` to true",
                ErrorCodes::SYNTAX_ERROR);
        }
        if (col_decl.default_expression)
        {
            ASTPtr default_expr =
                col_decl.default_specifier == "EPHEMERAL" && col_decl.default_expression->as<ASTLiteral>()->value.isNull() ?
                    std::make_shared<ASTLiteral>(DataTypeFactory::instance().get(col_decl.type)->getDefault()) :
                    col_decl.default_expression->clone();
            if (col_decl.type)
                column.type = name_type_it->type;
            else
            {
                column.type = defaults_sample_block.getByName(column.name).type;