Re: Allow WAL information to recover corrupted pg_controldata

>> I believe if WAL files are proper as mentioned in Alvaro's mail, the
purposed logic should generate
>> correct values.
>> Do you see any problem in logic purposed in my original mail.
>> Can I resume my work on this feature?

> Maybe I'm missing your point, but... why don't you just use PITR to
> recover from the corruption of pg_control?

AFAIK PITR can be used in a scenario where there is a base back-up and we
have archived
the WAL files after that, now it can use WAL files to apply on base-backup.

In this scenario we don't know a point from where to start the next replay. 
So I believe it will be difficult to use PITR in this scenario.


-----Original Message-----
From: Fujii Masao [mailto:masao.fujii@gmail.com] 
Sent: Tuesday, June 19, 2012 7:44 PM
To: Amit Kapila
Cc: Tom Lane; Alvaro Herrera; Cédric Villemain; Pg Hackers; Robert Haas
Subject: Re: [HACKERS] Allow WAL information to recover corrupted
pg_controldata

On Tue, Jun 19, 2012 at 2:44 AM, Amit Kapila <amit.kapila@huawei.com> wrote:
>> AFAIR you can create pg_control from scratch already with pg_resetxlog.
>> The hard part is coming up with values for the counters, such as the
>> next WAL location.  Some of them such as next OID are pretty harmless
>> if you don't guess right, but I'm worried that wrong next WAL could
>> make things worse not better.
>
> I believe if WAL files are proper as mentioned in Alvaro's mail, the
purposed logic should generate
> correct values.
> Do you see any problem in logic purposed in my original mail.
> Can I resume my work on this feature?

Maybe I'm missing your point, but... why don't you just use PITR to
recover from the corruption of pg_control?

Regards,

-- 
Fujii Masao