Re: NOT IN subquery optimization

Поиск
Список
Период
Сортировка
От Tom Lane
Тема Re: NOT IN subquery optimization
Дата
Msg-id 5699.1551650765@sss.pgh.pa.us
обсуждение исходный текст
Ответ на Re: NOT IN subquery optimization  (David Rowley <david.rowley@2ndquadrant.com>)
Ответы Re: NOT IN subquery optimization
Список pgsql-hackers
David Rowley <david.rowley@2ndquadrant.com> writes:
> On Mon, 4 Mar 2019 at 04:42, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> You absolutely will get errors during btree insertions and searches
>> if a datatype's btree comparison functions ever return NULL (for
>> non-NULL inputs).

> I understand this is the case if an index happens to be used, but
> there's no guarantee that's going to be the case. I was looking at the
> case where an index was not used.

Not following your point?  An index opclass is surely not going to be
designed on the assumption that it can never be used in an index.
Therefore, its support functions can't return NULL unless the index AM
allows that.

            regards, tom lane


В списке pgsql-hackers по дате отправления:

Предыдущее
От: David Rowley
Дата:
Сообщение: Re: NOT IN subquery optimization
Следующее
От: David Rowley
Дата:
Сообщение: Re: NOT IN subquery optimization