Re: Statistics on a table

On Tue, 8 Jul 2003, Maksim Likharev wrote:

> Hi,
> I just found very interesting situation,
> statistic ( n_distinct in particular) records for one of my columns,
> greatly under calculated it saying:
>
> 49726, but in reality 33409816.
>
> So planer never choose index but rather using table scan, and query
> never returns,
> is it any way how I can improve that?

You might see if raising the statistics target with ALTER TABLE ALTER
COLUMN followed by an analyze helps getting reasonable values any.  Maybe
try a few thousand?

> I can turn seqscan off but is it safe?

It's somewhat of a large hammer, especially if you're doing joins with
this table or something.