Re: [HACKERS] Autovacuum loose ends

On Fri, Jul 29, 2005 at 03:33:09PM -0400, Tom Lane wrote:

> It occurs to me that vacuuming to prevent XID wraparound is not the only
> reason to do DB-wide vacuums: we also need to keep
> pg_database.datvacuumxid from getting too old, else we will have
> problems with clog bloat.  We may need to rethink the test used.

Hmm.  I have a patch for this, but now that it's ready, I wonder if it's
really needed.  If I understand vacuum_set_xid_limits() correctly, it's
very difficult for the vacuumxid to be far behind the freeze limit.  And
in the case it's actually behind, then there's nothing we can do -- the
only way out is for the user to end the long-running transaction.

--
Alvaro Herrera (<alvherre[a]alvh.no-ip.org>)
"Cómo ponemos nuestros dedos en la arcilla del otro. Eso es la amistad; jugar
al alfarero y ver qué formas se pueden sacar del otro" (C. Halloway en
La Feria de las Tinieblas, R. Bradbury)