On 2013-05-09 12:09:04 -0400, Robert Haas wrote:
> On Mon, Mar 25, 2013 at 4:31 PM, Josh Berkus <josh@agliodbs.com> wrote:
> > In the past, setting vacuum_freeze_min_age (vfma) really low (say to
> > 10000 or 50000) would have caused lots of extra writing work due to
> > dirtying extra pages for freezing. This has been our stated reason to
> > keep vfma high, despite the obvious advantage of freezing tuples while
> > they're still in the cache.
>
> That, and Tom's concern about forensics, which I understand to be the
> larger sticking point.
FWIW I found having sensible xmin/xmax repeatedly really useful for
debugging problems. Most problems don't get noticed within minutes so
loosing evidence that fast is bad.
Greetings,
Andres Freund
--
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
