Executable settings like `max_command_execution_time` or `command_termination_timeout` cannot be set for `executable()` table function at all. Which means that the hardcoded values will be used.
I suggest to add it to executable function definition.
The simplest way is:
```
SELECT * FROM executable('<script name>', '<format>', (SET max_command_execution_time=100), (SELECT * FROM table))
```
As executable constructor already parses input `SELECT` statements anyway, adding `SET` statement there seems pretty logical.
Ideas? Any other better API?
I can implement that one.
{
    ASTs elements;
    auto parse_element = [&]
    {
        ASTPtr element;
        if (!elem_parser->parse(pos, element, expected))
            return false;
        elements.push_back(element);
        return true;
    };
    if (!parseUtil(pos, expected, parse_element, *separator_parser, allow_empty))
        return false;
    auto list = std::make_shared<ASTExpressionList>(result_separator);
    list->children = std::move(elements);
    node = list;
    return true;
}
bool ParserUnionList::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)