Re: [ADMIN] Processing very large TEXT columns (300MB+) using C/libpq

Поиск
Список
Период
Сортировка
От Geoff Winkless
Тема Re: [ADMIN] Processing very large TEXT columns (300MB+) using C/libpq
Дата
Msg-id CAEzk6fe8w+-MXxApaR5pAxCHmHRP=D2jgtBO0XwDu7Jew6aM=g@mail.gmail.com
обсуждение исходный текст
Ответ на Re: [ADMIN] Processing very large TEXT columns (300MB+) using C/libpq  (Bear Giles <bgiles@coyotesong.com>)
Ответы Re: [ADMIN] Processing very large TEXT columns (300MB+) using C/libpq  (Bear Giles <bgiles@coyotesong.com>)
Список pgsql-admin
Дерево обсуждения
On 20 October 2017 at 18:52, Bear Giles <bgiles@coyotesong.com> wrote:
As an aside any halfway decent optimizer would realize that the results of strlen() are unchanging as long as the contents of what it's passed isn't modified. That's a common enough pattern that it should be checked.

​IME this is a myth perpetuated by bad computer science lecturers who haven't thought through the consequences of what they're saying.​ strlen() can change because of changes inside the loop but also because of also threads in the system; I've not yet seen a compiler optimise that away, and neither should it, IMO.

G

В списке pgsql-admin по дате отправления:

Предыдущее
От: Bear Giles
Дата:
Сообщение: Re: [ADMIN] Processing very large TEXT columns (300MB+) using C/libpq
Следующее
От: Bear Giles
Дата:
Сообщение: Re: [ADMIN] Processing very large TEXT columns (300MB+) using C/libpq