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

Hi,

On 2013-06-16 17:19:49 -0700, Josh Berkus wrote:
> Amit posted a new version of this patch on January 23rd. But last
> comment on it by Tom is "not sure everyone wants this".
>
> https://commitfest.postgresql.org/action/patch_view?id=905

> ... so, what's the status of this patch?

That comment was referencing a mail of mine - so perhaps I better
explain:

I think the usecase for this utility isn't big enough to be included in
postgres since it really can only help in a very limited
circumstances. And I think it's too likely to be misused for stuff it's
not useable for (e.g. remastering).

The only scenario I see is that somebody deleted/corrupted
pg_controldata. In that scenario the tool is supposed to be used to find
the biggest lsn used so far so the user then can use pg_resetxlog to set
that as the wal starting point.
But that can be way much easier solved by just setting the LSN to
something very, very high. The database cannot be used for anything
reliable afterwards anyway.

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services