Re: AW: Is stats update during COPY IN really a good idea?

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Zeugswetter Andreas SB <ZeugswetterA(at)wien(dot)spardat(dot)at>
Cc: "'Tom Lane'" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: AW: Is stats update during COPY IN really a good idea?
Date: 2001-05-22 11:53:31
Message-ID: 200105221153.f4MBrVU29854@candle.pha.pa.us
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>
> > 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(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
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