Re: Sync Rep v17

On Tue, 2011-03-01 at 15:25 +0900, Fujii Masao wrote:
> On Tue, Mar 1, 2011 at 9:19 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> > On Mon, 2011-02-28 at 18:40 +0000, Simon Riggs wrote:
> >> > SyncRepReleaseWaiters should be called when walsender exits. Otherwise,
> >> > if the standby crashes while a transaction is waiting for replication,
> >> > it waits infinitely.
> >>
> >> Will think on this.
> >
> > The behaviour seems correct to me:
> >
> > If allow_standalone_primary = off then you wish to wait forever (at your
> > request...)
>
> No, I've never wished wait-forever option for now. I'd like to make
> the primary work alone when there is no connected standby, for
> high-availability.

Good news, please excuse that reference.

> > If allow_standalone_primary = on then we sit and wait until we hit
> > client timeout, which occurs even after last standby has gone.
>
> In that case, why do backends need to wait until the timeout occurs?
> We can make those backends resume their transaction as soon as
> the last standby has gone. No?

The guarantee provided is that we will wait for up to client timeout for
the sync standby to confirm. If we stop waiting right at the point that
an "event" occurs, it breaks the whole purpose of the feature.

--
Simon Riggs http://www.2ndQuadrant.com/books/
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