Re: Incorrect expected rows by ANALYZE

On Mon, 7 Apr 2003 pgsql(at)mohawksoft(dot)com wrote:

> > Kenji Sugita <sugita(at)srapc1327(dot)sra(dot)co(dot)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.