On Wed, Jun 9, 2010 at 12:09 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> If you
>> freeze all tuples by the time the pages are marked all-visible,
>> perhaps via the xmin-preserving mechanism Simon suggested, then you
>> can use the visibility map to skip anti-wraparound vacuum as well as
>> regular vacuum. That sounds to me like it's accomplishing something.
>> Is it a complete solution? No. Is it better than what we have now?
>> Yes.
>
> I do like the idea of using a status bit rather than FrozenXid to mark a
> frozen tuple, because that eliminates the conflict between wanting to
> freeze aggressively for performance reasons and wanting to preserve Xids
> for forensic reasons. But it doesn't seem to do much for Josh's
> original problem.
OK, I see. So maybe we add a Todo to implement that, and then keep
thinking about how to fix Josh's problem.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company
