Re: what to revert
От | Amit Kapila |
---|---|
Тема | Re: what to revert |
Дата | |
Msg-id | CAA4eK1LkQy_tmGHydjkkORYjfrPTU_uiPcxZaFDvitNnvWd7ow@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: what to revert (Andres Freund <andres@anarazel.de>) |
Список | pgsql-hackers |
On Thu, May 5, 2016 at 8:44 AM, Andres Freund <andres@anarazel.de> wrote:
>
> On 2016-05-05 06:08:39 +0300, Ants Aasma wrote:
> > On 5 May 2016 1:28 a.m., "Andres Freund" <andres@anarazel.de> wrote:
> > > On 2016-05-04 18:22:27 -0400, Robert Haas wrote:
> > > > How would the semantics change?
> > >
> > > Right now the time for computing the snapshot is relevant, if
> > > maintenance of xids is moved, it'll likely be tied to the time xids are
> > > assigned. That seems perfectly alright, but it'll change behaviour.
> >
> > FWIW moving the maintenance to a clock tick process will not change user
> > visible semantics in any significant way. The change could easily be made
> > in the next release.
>
> I'm not convinced of that - right now the timeout is computed as a
> offset to the time a snapshot with a certain xmin horizon is
> taken.
>
> On 2016-05-05 06:08:39 +0300, Ants Aasma wrote:
> > On 5 May 2016 1:28 a.m., "Andres Freund" <andres@anarazel.de> wrote:
> > > On 2016-05-04 18:22:27 -0400, Robert Haas wrote:
> > > > How would the semantics change?
> > >
> > > Right now the time for computing the snapshot is relevant, if
> > > maintenance of xids is moved, it'll likely be tied to the time xids are
> > > assigned. That seems perfectly alright, but it'll change behaviour.
> >
> > FWIW moving the maintenance to a clock tick process will not change user
> > visible semantics in any significant way. The change could easily be made
> > in the next release.
>
> I'm not convinced of that - right now the timeout is computed as a
> offset to the time a snapshot with a certain xmin horizon is
> taken.
Here are you talking about snapshot time (snapshot->whenTaken) which is updated at the time of GetSnapshotData()?
В списке pgsql-hackers по дате отправления: