Re: [HACKERS] Index not used on simple select

Поиск
Список
Период
Сортировка
От Ole Gjerde
Тема Re: [HACKERS] Index not used on simple select
Дата
Msg-id Pine.LNX.4.05.9907231445360.8120-100000@snowman.icebox.org
обсуждение исходный текст
Ответ на Re: [HACKERS] Index not used on simple select  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы UPDATE memory exhaustion
Список pgsql-hackers
On Fri, 23 Jul 1999, Tom Lane wrote:
> It looks like the highly skewed distribution of nsn values (what you
> sent me had 997 '' entries, only 3 non-empty strings) is confusing the

As a note, it doesn't seem to matter wether the field has '' or NULL.
Even after I do a update to set all all rows with '' to NULL, it still
does the same thing.

Also, my full set of data is not quite so skewed.  The nsn field has about
450,000 non-empty rows in it.

Thanks,
Ole Gjerde




В списке pgsql-hackers по дате отправления:

Предыдущее
От: Oleg Bartunov
Дата:
Сообщение: vacuum analyze problem
Следующее
От: Tom Lane
Дата:
Сообщение: Re: [HACKERS] Re: SSL patch