> -----Original Message-----
> From: Bruce Momjian [mailto:pgman@candle.pha.pa.us]
>
> > Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > > That certainly would make sense. We have hesitated to gather more
> > > statistics because of the time involved. Fuller statistics
> on just the
> > > indexed columns could be a big win and be done fairly quickly because
> > > the rows are already sorted in the index.
> >
> > Yeah, a scan over just the index itself would be a perfect way to
> > gather stats. The normal objection to it (can't tell whether entries
> > correspond to currently-valid tuples) doesn't apply, because we don't
> > really care whether the stats are perfectly accurate.
> >
> > Should put this in TODO, along with something about splitting the
> > ANALYZE function out of VACUUM and making it invokable as a separate
> > statement.
>
> Added:
>
> * Remove ANALYZE from VACUUM so it can be run separately without locks
> * Gather more accurate statistics using indexes
>
Gathering statistics using indexes on-fly is best.
However VACUUM(without ANALYZE) already scans all indexes using
vc_scanoneind()/vc_vaconeind(). Isn't it availble anyway ?
Regards.
Hiroshi Inoue
Inoue@tpf.co.jp
