Re: BUG #5530: Default cost of crypt causes poor decisions

Поиск
Список
Период
Сортировка
От Tom Lane
Тема Re: BUG #5530: Default cost of crypt causes poor decisions
Дата
Msg-id 25610.1277850091@sss.pgh.pa.us
обсуждение исходный текст
Ответ на BUG #5530: Default cost of crypt causes poor decisions  ("Baegle" <al@wifiny.org>)
Список pgsql-bugs
"Baegle" <al@wifiny.org> writes:
> The default cost of crypt() is 1, but crypt is intentionally a high cost
> function. This mis-match between assigned cost and actual cost causes the
> query planner to use crypt too soon and slows down execution of queries
> significantly. The cost of the function should be more congruent with it's
> intended cost.

Perhaps, but the same could be said of most of the contrib/pgcrypto
functions, no?  Which ones do you think should have a nondefault cost,
and what should we set it to?

Also, it'd be easier to persuade people this is worth worrying about if
you showed a real-world case where it's a problem.  crypt() doesn't seem
like a function that would be very likely to be used in contexts where
this'd matter.

            regards, tom lane

В списке pgsql-bugs по дате отправления:

Предыдущее
От: Tom Lane
Дата:
Сообщение: Re: Function works in 8.4 but not in 9.0 beta2 "ERROR: structure of query does not match function result type"
Следующее
От: Bruce Momjian
Дата:
Сообщение: Re: local_preload_libraries filenames converted to lowercase