Re: preserving forensic information when we freeze

On 05/28/2013 06:21 AM, Robert Haas wrote:
> As a general statement, I view this work as something that is likely
> needed no matter which one of the "remove freezing" approaches that
> have been proposed we choose to adopt.  It does not fix anything in
> and of itself, but it (hopefully) removes an objection to the entire
> line of inquiry.

Agreed.  I have some ideas on how to reduce the impact of freezing as
well (of course), and the description of your approach certainly seems
to benefit them, especially as it removes the whole "forensic
information" objection.

One question though: if we're not removing the xmin, how do we know the
maximum xid to which we can prune clog?  I can imagine several ways
given your approach.

-- 
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com