Re: [HACKERS] getting rid of SnapshotNow

Поиск
Список
Период
Сортировка
От Alvaro Herrera
Тема Re: [HACKERS] getting rid of SnapshotNow
Дата
Msg-id 20130719162932.GA4130@eldon.alvh.no-ip.org
обсуждение исходный текст
Ответ на Re: [HACKERS] getting rid of SnapshotNow  (Robert Haas <robertmhaas@gmail.com>)
Ответы Re: [HACKERS] getting rid of SnapshotNow  (Robert Haas <robertmhaas@gmail.com>)
Список pgsql-odbc
Robert Haas escribió:
> On Fri, Jul 19, 2013 at 1:27 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:

> > Why not tell people to use SnapshotDirty if they need a
> > not-guaranteed-consistent result?  At least then it's pretty obvious
> > that you're getting some randomness in with your news.

> On further reflection, I think perhaps pgrowlocks should just register
> a fresh MVCC snapshot and use that.  Using SnapshotDirty would return
> TIDs of unseen tuples, which does not seem to be what is wanted there.

I think seeing otherwise invisible rows is useful in pgrowlocks.  It
helps observe the effects on tuples written by concurrent transactions
during experimentation.  But then, maybe this functionality belongs in
pageinspect instead.

--
Álvaro Herrera                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services


В списке pgsql-odbc по дате отправления:

Предыдущее
От: Tom Lane
Дата:
Сообщение: Re: [HACKERS] getting rid of SnapshotNow
Следующее
От: Robert Haas
Дата:
Сообщение: Re: [HACKERS] getting rid of SnapshotNow