Re: Synchronized snapshots versus multiple databases

From: Andrew Dunstan <andrew(at)dunslane(dot)net>
To: Florian Pflug <fgp(at)phlo(dot)org>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: Synchronized snapshots versus multiple databases
Date: 2011-10-21 16:37:30
Message-ID: 4EA19FCA.30904@dunslane.net
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On 10/21/2011 12:05 PM, Florian Pflug wrote:
> On Oct21, 2011, at 17:36 , Tom Lane wrote:
>> 1. Restrict exported snapshots to be loaded only by transactions running
>> in the same database as the exporter. This would fix the problem, but
>> it cuts out one of the main use-cases for sync snapshots, namely getting
>> cluster-wide-consistent dumps in pg_dumpall.
> Isn't the use-case getting consistent *parallel* dumps of a single database
> rather than consistent dump of multiple databases? Since we don't have atomic
> cross-database commits, what does using the same snapshot to dump multiple
> databases buy us?

That was my understanding of the use case.

cheers

andrew

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