Re: Use pg_rewind when target timeline was switched

On Fri, Sep 18, 2015 at 12:34 PM, Michael Paquier
<michael(dot)paquier(at)gmail(dot)com> wrote:
> On Fri, Sep 18, 2015 at 9:00 AM, Alexander Korotkov wrote:
>> BTW, it would be an option to generate system_identifier to each new
>> timeline, by analogy of initdb do for the whole WAL.
>> Having such system_identifiers we can distinguish different timeline which
>> have assigned same ids.
>> Any thoughts?
>
> If you mean a new field incorporated in XLogLongPageHeader and
> ControlFile to ensure that a new timeline generated is unique across
> the same installation identified with system_identifier, then I'm not
> against it for something up to 2 bytes (even 1 byte would be fine),

Er, 2 bytes may be a bad idea as well, 1/16k% chance of collision
looks dangerous when rewinding a node... It could cause silent data
corruption on the standby being rewounded.
--
Michael