On Mon, 7 Apr 2003 pgsql@mohawksoft.com wrote:
> > Kenji Sugita <sugita@srapc1327.sra.co.jp> writes:
> >> Why do dead tuples cause incorrect expected rows by ANALYZE?
> >
> > Because it extrapolates the density of live rows in the whole table
> > from their density in the first few pages.
> >
> > There has been some previous discussion of how to improve this, but no
> > really workable ideas AFAIR. Ultimately, unless you want to abandon
> > the notion that ANALYZE only samples the table and doesn't read the
> > whole thing, there will be situations where it gets fooled. But
> > possibly we can make those situations less likely to correspond to
> > common real-world cases.
>
> Couldn't there be an ANALYZE FULL option?
There's something close, that is, you can change the statistics target for
a column in a table like so:
ALTER TABLE [ ONLY ] table [ * ] ALTER [ COLUMN ] column SET STATISTICS integer
which can make it so that more of the rows are analyzed.
