
> We have a TODO item
> 	* Update reltuples in COPY
> 
> I was just about to go do this when I realized that it may not be such
> a hot idea after all.

Imho it is not a good idea at all. The statistics are a very sensitive area,
that imho should only be calculated on request. I already don't like the
statistics that are implicitly created during create index.

Eighter you have online stats keeping or you don't.
For me this is a definite all or nothing issue. Anything inbetween is 
only good for unpleasant surprises.

I have very strong feelings about this, because of bad experience.
I would be willing to go into detail.

A syntactic extension to copy ("with analyze") on the other hand would 
be a feature.

Andreas

Tue, 22 May 2001 09:19:53 +0200
Zeugswetter Andreas SB  <ZeugswetterA@wien.spardat.at>
AW: Is stats update during COPY IN really a good idea?
[ Charset ISO-8859-1 unsupported, converting... ]
> 
> > We have a TODO item
> > 	* Update reltuples in COPY
> > 
> > I was just about to go do this when I realized that it may not be such
> > a hot idea after all.
> 
> Imho it is not a good idea at all. The statistics are a very sensitive area,
> that imho should only be calculated on request. I already don't like the
> statistics that are implicitly created during create index.

OK, if you feel strongly, and Tom does, I will remove the item. 
However, just remember that pg_class already has a row count that we
force in there by default.

	test=> create table test (x int);
	CREATE
	test=> select reltuples from pg_class where relname = 'test';
	 reltuples 
	-----------
	      1000
	(1 row)

I was just suggesting we make that accurate if we can, even if we can
make it accurate only 80% of the time.  Once we INSERT, it isn't
accurate anymore anyway.  This is just an estimate, and in my mind, it
doesn't have to be accurate in all cases.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

Tue, 22 May 2001 07:53:31 -0400 (EDT)
Bruce Momjian <pgman@candle.pha.pa.us>
Re: AW: Is stats update during COPY IN really a good idea?