Re: pg_upgrade and statistics

On Tue, Mar 13, 2012 at 12:08:41PM -0300, Alvaro Herrera wrote:
> > > You're wrong.  Autovacuum does not consider time, only dead/live tuple
> > > counts.  The formulas it uses are in the autovacuum docs; some details
> > > (such as the fact that it skips tables that do not have stat entries)
> > > might be missing.
> > 
> > Oh, yes.  Thank you for the correction;  not sure what I was thinking.
> > 
> > How would they trigger an autovacuum then?
> 
> We don't have any mechanism to trigger it currently.  Maybe we could
> inject fake messages to the stats collector so that it'd believe the
> tables have lots of new tuples and an analyze is necessary.

Ewe!  Yes, I thought some more and realized these are system _views_,
meaning we can't just update them with UPDATE.  It sounds like something
pg_upgrade will have to do with a server-side function, someday.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +