Re: Why we lost Uber as a user

On 28 Jul 2016 12:19, "Vitaly Burovoy" <vitaly(dot)burovoy(at)gmail(dot)com> wrote:
>
> On 7/28/16, Geoff Winkless <pgsqladmin(at)geoff(dot)dj> wrote:
> > On 27 July 2016 at 17:04, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> >
> >> Well, their big complaint about binary replication is that a bug can
> >> spread from a master to all slaves, which doesn't happen with statement
> >> level replication.
> >
> > ​
> > I'm not sure that that makes sense to me. If there's a database bug that
> > occurs when you run a statement on the master, it seems there's a decent
> > chance that that same bug is going to occur when you run the same
statement
> > on the slave.
> >
> > Obviously it depends on the type of bug and how identical the slave is,
but
> > statement-level replication certainly doesn't preclude such a bug from
> > propagating.
> >
> > ​Geoff
>
> Please, read the article first! The bug is about wrong visibility of
> tuples after applying WAL at slaves.
> For example, you can see two different records selecting from a table
> by a primary key (moreover, their PKs are the same, but other columns
> differ).

I read the article. It affected slaves as well as the master.

I quote:
"because of the way replication works, this issue has the potential to
spread into all of the databases in a replication hierarchy"

I maintain that this is a nonsense argument. Especially since (as you
pointed out and as I missed first time around) the bug actually occurred at
different records on different slaves, so he invalidates his own point.

Geoff