Message-ID: <1434284619.3638.10.camel@gmail.com>
Subject: Re: replication consistency checking
From: jaime soler <jaime.soler@gmail.com>
Reply-To: jaime.soler@gmail.com
To: hydra <hydrapolic@gmail.com>
Cc: pgsql-admin <pgsql-admin@postgresql.org>
Date: Sun, 14 Jun 2015 14:23:39 +0200
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El jue, 11-06-2015 a las 07:14 +0200, hydra escribió:
> 
> 
> On Tue, Jun 9, 2015 at 9:47 PM, Jan Lentfer <Jan.Lentfer@web.de>
> wrote:
>         
>         
>         
>         
>         > Am 05.06.2015 um 16:56 schrieb Scott Ribe
>         <scott_ribe@elevated-dev.com>:
>         >
>         >> On Jun 5, 2015, at 8:42 AM, Igor Neyman
>         <ineyman@perceptron.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@postgresql.org 

> 
>  
>         
>         > 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
> 
> 


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