Re: Patch for fail-back without fresh backup

On 16 June 2013 17:25, Samrat Revagade <revagade(dot)samrat(at)gmail(dot)com> wrote:
>
>
> On Sun, Jun 16, 2013 at 5:10 PM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>>
>>
>>
>> So I strongly object to calling this patch anything to do with
>> "failback safe". You simply don't have enough data to make such a bold
>> claim. (Which is why we call it synchronous replication and not "zero
>> data loss", for example).
>>
>> But that's not the whole story. I can see some utility in a patch that
>> makes all WAL transfer synchronous, rather than just commits. Some
>> name like synchronous_transfer might be appropriate. e.g.
>> synchronous_transfer = all | commit (default).
>>
>
> I agree with you about the fact that,
> Now a days the need of fresh backup in crash recovery seems to be a major
> problem.
> we might need to change the name of patch if there other problems too with
> crash recovery.

(Sorry don't understand)

>> The idea of another slew of parameters that are very similar to
>> synchronous replication but yet somehow different seems weird. I can't
>> see a reason why we'd want a second lot of parameters. Why not just
>> use the existing ones for sync rep? (I'm surprised the Parameter
>> Police haven't visited you in the night...) Sure, we might want to
>> expand the design for how we specify multi-node sync rep, but that is
>> a different patch.
>>
>
> The different set of parameters are needed to differentiate between
> fail-safe standby and synchronous standby, the fail-safe standby and standby
> in synchronous replication can be two different servers.

Why would they be different? What possible reason would you have for
that config? There is no *need* for those parameters, the proposal
could work perfectly well without them.

Let's make this patch fulfill the stated objectives, not add in
optional extras, especially ones that don't appear well thought
through. If you wish to enhance the design for the specification of
multi-node sync rep, make that a separate patch, later.

--
Simon Riggs http://www.2ndQuadrant.com/
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