Re: Function execution costs 'n all that
От | Neil Conway |
---|---|
Тема | Re: Function execution costs 'n all that |
Дата | |
Msg-id | 1168887288.6174.109.camel@localhost.localdomain обсуждение исходный текст |
Ответ на | Re: Function execution costs 'n all that (Richard Troy <rtroy@ScienceTools.com>) |
Ответы |
Re: Function execution costs 'n all that
Re: Function execution costs 'n all that Re: Function execution costs 'n all that |
Список | pgsql-hackers |
On Mon, 2007-01-15 at 10:51 -0800, Richard Troy wrote: > I therefore propose that the engine evaluate - > benchmark, if you will - all functions as they are ingested, or > vacuum-like at some later date (when valid data for testing may exist), > and assign a cost relative to what it already knows - the built-ins, for > example. That seems pretty unworkable. It is unsafe, for one: evaluating a function may have side effects (inside or outside the database), so the DBMS cannot just invoke user-defined functions at whim. Also, the relationship between a function's arguments and its performance will often be highly complex -- it would be very difficult, not too mention computationally infeasible, to reconstruct that relationship automatically, especially without any real knowledge about the function's behavior. -Neil
В списке pgsql-hackers по дате отправления: