> On Tue, 28 Aug 2001, Reinoud van Leeuwen wrote:
>
>> Can somebody explain to me:
>>
>> > radius=# explain select count (radiuspk) from radius ;
>> > NOTICE: QUERY PLAN:
>> >
>> > Aggregate (cost=12839.79..12839.79 rows=1 width=8)
>> > -> Seq Scan on radius (cost=0.00..11843.43 rows=39854
On Tue, 28 Aug 2001, Reinoud van Leeuwen wrote:
> Can somebody explain to me:
>
> > radius=# explain select count (radiuspk) from radius ;
> > NOTICE: QUERY PLAN:
> >
> > Aggregate (cost=12839.79..12839.79 rows=1 width=8)
> > -> Seq Scan on radius (cost=0.00..11843.43 rows=398543 width=8)
Reinoud van Leeuwen writes:
> > radius=# select count (radiuspk) from radius ;
> > count
> >
> > 398543
> > (1 row)
>
> This query takes about 3 seconds. But the query plan *already* knows the
> number of rows ("rows=398543").
This is only an estimate which is only updated by VACUU
Can somebody explain to me:
> radius=# explain select count (radiuspk) from radius ;
> NOTICE: QUERY PLAN:
>
> Aggregate (cost=12839.79..12839.79 rows=1 width=8)
> -> Seq Scan on radius (cost=0.00..11843.43 rows=398543 width=8)
>
> EXPLAIN
This query answers me *instantly* after hitting r