Re: Counting all rows

On Saturday 23 June 2007 05:38:56 Andreas Kretschmer wrote:
> Stefan Arentz <stefan(dot)arentz(at)gmail(dot)com> schrieb:
> > I need to get statistics from a bunch of tables. Simply the number of
> > records in them.
> >
> > The query plan looks like this:
> >
> > => explain select count(id) from stuff;
> > QUERY PLAN
> > -------------------------------------------------------------------
> > Aggregate (cost=1629.69..1629.70 rows=1 width=8)
> > -> Seq Scan on stuff (cost=0.00..1517.75 rows=44775 width=8)
> >
> > The sequential scan kind of worries me. Is there a better/faster way to
> > do this?
>
> Yes.
>
> A "select count(*) from foo;" enforces a seq. scan. Solutions for this
> are discussed here: http://www.varlena.com/GeneralBits/120.php
>
>
> Andreas

Is there any neat trick for doing this for paging estimates? It looks like
the only way to get a result count from a more complex query is to either
fetch a count first, or to fetch all records and count them in the
application.

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