Re: How Postgresql Compares... Count(*) and others

Поиск
Список
Период
Сортировка
От Tom Lane
Тема Re: How Postgresql Compares... Count(*) and others
Дата
Msg-id 499.995773781@sss.pgh.pa.us
обсуждение исходный текст
Ответ на How Postgresql Compares... Count(*) and others  (Mark kirkwood <markir@slingshot.co.nz>)
Ответы Re: How Postgresql.... Putting Count(*) To Bed (Hopefully)
Список pgsql-general
Дерево обсуждения 
Mark kirkwood <markir@slingshot.co.nz> writes:
> I have not tried to see if it makes any difference in Postgresql...

Postgres converts count(*) to count(1) at the grammar stage (cf. gram.y,
about line 4817 in current sources).  So if you think you detect any
performance difference, you're surely hallucinating...

            regards, tom lane

В списке pgsql-general по дате отправления: