Re: adding a new column in IDENTIFY_SYSTEM

On Sun, May 15, 2011 at 6:03 PM, Jaime Casanova <jaime@2ndquadrant.com> wrote:
> On Thu, May 5, 2011 at 10:59 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Magnus Hagander <magnus@hagander.net> writes:
>>>> So even if people don't believe in the rationale behind the patch,
>>>> would allowing it harm anything at this point?
>>
>>> Adding it for the sake of upgrades seems very far fetched.
>>
>>> Adding it for the sake of giving a better error message seems like a
>>> very good idea. But in that case, the client side code to actually
>>> give a better error message should be included from the start, IMHO.
>>
>> What's not apparent to me is how we'll even get to this check; if
>> there's a mismatch, won't the database system identifier comparison
>> fail first in most scenarios?
>>
>
> that's why i didn't propose that to begin with... but thinking on
> that, we can use it to add a message in pg_basebackup, maybe just a
> warning if we are taking a basebackup from an incompatible system...
>
> but for that i will need to add xlog_internal.h and postgres.h to
> pg_basebackup and use the "#define FRONTEND 1" hack we have in
> pg_resetxlog
>

attached, comments?

--
Jaime Casanova         www.2ndQuadrant.com
Professional PostgreSQL: Soporte y capacitación de PostgreSQL