Re: Query optimizer 8.0.1 (and 8.0)

Поиск
Список
Период
Сортировка
От Tom Lane
Тема Re: Query optimizer 8.0.1 (and 8.0)
Дата
Msg-id 27032.1107790330@sss.pgh.pa.us
обсуждение исходный текст
Ответ на Re: Query optimizer 8.0.1 (and 8.0)  (pgsql@mohawksoft.com)
Ответы Re: Query optimizer 8.0.1 (and 8.0)  (pgsql@mohawksoft.com)
Список pgsql-hackers
pgsql@mohawksoft.com writes:
> On a very basic level, why bother sampling the whole table at all? Why not
> check one block and infer all information from that? Because we know that
> isn't enough data. In a table of 4.6 million rows, can you say with any
> mathmatical certainty that a sample of 100 points can be, in any way,
> representative?

This is a statistical argument, not a rhetorical one, and I'm not going
to bother answering handwaving.  Show me some mathematical arguments for
a specific sampling rule and I'll listen.
        regards, tom lane


В списке pgsql-hackers по дате отправления:

Предыдущее
От: Tom Lane
Дата:
Сообщение: Re: Inline MemoryContextSwitchTo?
Следующее
От: Tom Lane
Дата:
Сообщение: Re: Thinking about breaking up the BufMgrLock