Re: preserving forensic information when we freeze

On Wed, Jul 3, 2013 at 8:07 PM, Andres Freund <andres(at)2ndquadrant(dot)com> wrote:
> On 2013-07-02 16:29:56 -0400, Robert Haas wrote:
>> There's no possibility of getting confused here; if X is still around
>> at all, it's xmax is of the same generation as Y's xmin. Otherwise,
>> we've had an undetected XID wraparound.
>
> Another issue I thought about is what we will return for SELECT xmin
> FROM blarg; Some people use that in their applications (IIRC
> skytools/pqg/londiste does so) and they might get confused if we
> suddently return xids from the future. On the other hand, not returning
> the original xid would be a shame as well...

Skytools/pqg/londiste use only txid_* APIs, they don't look at
4-byte xids on table rows.

--
marko