Re: Collect frequency statistics for arrays

Поиск
Список
Период
Сортировка
От Tom Lane
Тема Re: Collect frequency statistics for arrays
Дата
Msg-id 26664.1330557044@sss.pgh.pa.us
обсуждение исходный текст
Ответ на Re: Collect frequency statistics for arrays  (Nathan Boley <npboley@gmail.com>)
Ответы Re: Collect frequency statistics for arrays  (Nathan Boley <npboley@gmail.com>)
Список pgsql-hackers
Nathan Boley <npboley@gmail.com> writes:
> On Wed, Feb 29, 2012 at 2:43 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Nathan Boley <npboley@gmail.com> writes:
>>> If I understand you're suggestion, queries of the form
>>> SELECT * FROM rel
>>> WHERE ARRAY[ 1,2,3,4 ] <= x
>>> � � �AND x <=ARRAY[ 1, 2, 3, 1000];
>>> would no longer use an index. Is that correct?

>> No, just that we'd no longer have statistics relevant to that, and would
>> have to fall back on default selectivity assumptions.

> Which, currently, would mean queries of that form would typically use
> a table scan, right?

No, it doesn't.

> What about MCV's? Will those be removed as well?

Sure.  Those seem even less useful.
        regards, tom lane


В списке pgsql-hackers по дате отправления:

Предыдущее
От: Nathan Boley
Дата:
Сообщение: Re: Collect frequency statistics for arrays
Следующее
От: "A.M."
Дата:
Сообщение: Re: pg_upgrade --logfile option documentation