Re: Patch for fail-back without fresh backup

On Fri, Sep 27, 2013 at 5:18 PM, Pavan Deolasee
 wrote:
> On Fri, Sep 27, 2013 at 1:28 PM, Sawada Masahiko 
> wrote:
>>
>>
>> >
>>
>> Thank you for comment. I think it is good simple idea.
>> In your opinion, if synchronous_transfer is set 'all' and
>> synchronous_commit is set 'on',
>> the master wait for data flush eve if user sets synchronous_commit to
>> 'local' or 'off'.
>> For example, when user want to do transaction early, user can't do this.
>> we leave the such situation as constraint?
>>
>
> No, user can still override the transaction commit point wait. So if
>
> synchronous_transfer is set to "all":
>  - If synchronous_commit is ON - wait at all points
>  - If synchronous_commit is OFF - wait only at buffer flush (and other
> related to failback safety) points
>
> synchronous_transfer is set to "data_flush":
>  - If synchronous_commit is either ON o OFF - do not wait at commit points,
> but wait at all other points
>
> synchronous_transfer is set to "commit":
>  - If synchronous_commit is ON - wait at commit point
>  - If synchronous_commit is OFF - do not wait at any point
>

Thank you for explain. Understood.
if synchronous_transfer is set 'all' and user changes
synchronous_commit to 'off'( or 'local') at a transaction,
the master server wait at buffer flush, but doesn't wait at commit
points. Right?

In currently patch, synchronous_transfer works in cooperation with
synchronous_commit.
But if user changes synchronous_commit at a transaction, they are not
in cooperation.
So, your idea might be better than currently behaviour of synchronous_transfer.

Regards,

-------
Sawada Masahiko