Re: Standalone synchronous master - Mailing list pgsql-hackers

From Andres Freund
Subject Re: Standalone synchronous master
Date
Msg-id 20140108230438.GT14280@awork2.anarazel.de
Whole thread Raw
In response to Re: Standalone synchronous master  ("Joshua D. Drake" <jd@commandprompt.com>)
List pgsql-hackers
On 2014-01-08 14:52:07 -0800, Joshua D. Drake wrote:
> On 01/08/2014 02:46 PM, Andres Freund wrote:
> >>The idea is that we know that data on db0 is not written until we know for a
> >>fact that db1 also has that data. That is great and a guarantee of data
> >>integrity between the two nodes.
> >
> >That guarantee is never there. The only thing guaranteed is that the
> >client isn't notified of the commit until db1 has received the data.
> 
> Well ugh on that.. but that is for another reply.

You do realize that locally you have the same guarantees? If the client
didn't receive a reply to a COMMIT you won't know whether the tx
committed or not. If that's not sufficient you need to use 2pc and a
transaction manager.

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services



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