
> > Because we do not want the dba to decide which statistics are optimal,
> > there should probably be an analyze helper application that is invoked
> > with "vacuum analyze database optimal" or some such, that also decides 
> > whether a table was sufficiently altered to justify new stats gathering
> > or vacuum.
> 
> And on what are you going to base "sufficiently altered"?

Probably current table size vs table size in statistics and maybe timestamp
when statistics were last updated. Good would also be the active row count, but 
we don't have cheap access to the current value.

The point is, that if the combined effort of all "hackers" (with the help of 
some large scale users) cannot come to a more or less generally adequate answer, 
the field dba most certainly won't eighter.

Andreas

Mon, 18 Jun 2001 17:21:09 +0200
Zeugswetter Andreas SB  <ZeugswetterA@wien.spardat.at>
AW: AW: Call for alpha testing: planner statistics revi
	sion s
Zeugswetter Andreas SB  <ZeugswetterA@wien.spardat.at> writes:
>> And on what are you going to base "sufficiently altered"?

> Probably current table size vs table size in statistics and maybe
> timestamp when statistics were last updated. Good would also be the
> active row count, but we don't have cheap access to the current value.

Once we get done with online VACUUM and internal free space re-use
(which is next on my to-do list), growth of the physical file will be
a poor guide to number of updated tuples, too.  So the above proposal
reduces to "time since last update", for which we do not need any
backend support: people already run VACUUM ANALYZE from cron tasks.

> The point is, that if the combined effort of all "hackers" (with the
> help of some large scale users) cannot come to a more or less
> generally adequate answer, the field dba most certainly won't eighter.

True, but I regard your "if" as unproven.  The reason for this call for
alpha testing is to find out whether we have a good enough solution or
not.  I feel no compulsion to assume that it's not good enough on the
basis of no evidence.

			regards, tom lane

Mon, 18 Jun 2001 11:31:19 -0400
Tom Lane <tgl@sss.pgh.pa.us>
Re: AW: AW: Call for alpha testing: planner statistics revi sion s 