Horton

Re: Review: Patch to compute Max LSN of Data Pages

Andres Freund <andres@2ndquadrant.com>

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From: 'Andres Freund' <andres@2ndquadrant.com>
To: Amit Kapila <amit.kapila@huawei.com>
Cc: 'Hari Babu' <haribabu.kommi@huawei.com>, 'Robert Haas' <robertmhaas@gmail.com>, 'Josh Berkus' <josh@agliodbs.com>, pgsql-hackers@postgresql.org
Date: 2013-07-08T11:45:56Z
Lists: pgsql-hackers 
On 2013-07-08 17:10:43 +0530, Amit Kapila wrote:
> On Monday, July 08, 2013 4:26 PM Andres Freund wrote:
> > On 2013-07-08 16:17:54 +0530, Hari Babu wrote:
> > > +    This utility can also be used to decide whether backup is
> > required or not when the data page
> > > +    in old-master precedes the last applied LSN in old-standby
> > (i.e., new-master) at the
> > > +    moment of the failover.
> > > +   </para>
> > > +  </refsect1>
> > 
> > I don't think this is safe in any interesting set of cases. Am I
> > missing
> > something?
> 
> No, you are not missing anything. It can be only used to find max LSN in
> database which can avoid further corruption 

Why is the patch submitted documenting it as a use-case then? I find it
rather scary if the *patch authors* document a known unsafe use case as
one of the known use-cases.

Greetings,

Andres Freund

-- 
 Andres Freund	                   http://www.2ndQuadrant.com/
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