Re: replication consistency checking

On Sun, Jun 14, 2015 at 2:23 PM, jaime soler <jaime(dot)soler(at)gmail(dot)com> wrote:

> El jue, 11-06-2015 a las 07:14 +0200, hydra escribió:
> >
> >
> > On Tue, Jun 9, 2015 at 9:47 PM, Jan Lentfer <Jan(dot)Lentfer(at)web(dot)de>
> > wrote:
> >
> >
> >
> >
> > > Am 05.06.2015 um 16:56 schrieb Scott Ribe
> > <scott_ribe(at)elevated-dev(dot)com>:
> > >
> > >> On Jun 5, 2015, at 8:42 AM, Igor Neyman
> > <ineyman(at)perceptron(dot)com> wrote:
> > >>
> > >> The problem I see with “checksum utility” is that for it to
> > work both compared servers should be “static”: not
> > transactions while it does its job.
> > >
> > > Indeed, and that was brought up before and OP seems to be
> > ignoring it. What magic does MySQL (supposedly) use to compare
> > databases without interfering with updates?
> > >
> > Also, if I remember the Postgres SR bug correctly, this kind
> > of check that Percona provides would not have helped with this
> > kind of bug. The corruption did not occur *during* replication
> > but only if you restarted the slave because transactions were
> > falsely marked as commited or non-commited when the slave came
> > up again. You might have noticed the corruption earlier,
> > though.
> >
> >
> >
> > Ok but we do restart our slaves from time to time (upgrades) so sooner
> > or later you would discover if that would be the problem. But maybe it
> > will discover bugs/problems that occur *during* replication.
>
> Are you or your company considering to fund "this tool"?, if yes, maybe
> you get some feedback at pgsql-hackers(at)postgresql(dot)org
>
>
Hello,
at first I wanted to know whether something is done in this area. I've only
find pg_comparator:
http://www.cri.ensmp.fr/~coelho/pg_comparator/pg_comparator.html

but haven't tested yet. If I don't find anything usable I will consider
your advice. But I'm just an IT admin doing my job so it's not my decision.
However thanks for the idea.

> >
> >
> >
> > > One could imagine a built-in feature in PG which depends on
> > using MVCC and having both sides look at the same snapshot.
> > (Which would require repeatable reads.)
> > I actually think this would a need thing to have (for
> > pre-production) test environments, like alpha or beta testing.
> >
> > Jan
> >
> >
>
>
>