Re: sql query not using indexes

On Wed, 20 Sep 2000, User Lenzi wrote:

> if I start a query:
>
> explain select * from teste where login = 'xxx'
> results:
> Index Scan using teste1 on teste (cost=0.00..97.88 rows=25 )
>
>
> however a query:
> explain select * from teste where login > 'AAA'
> results:
> Seq Scan on teste ....
>
>
> On a machine running version 6.5 both queries results index scan.
>
> this results that the version 6.5 is faster than version 7.0.2 on this
> kind of
> query.
>
>
> Any explanation???

Have you done a vacuum analyze on the table? Also, what does the row
count for the second query look like? It's probably deciding that
there are too many rows that will match login >'AAA' for index scan
to be cost effective. So, actually, also, what does
select count(*) from teste where login>'AAA" give you on the 7.0.2 box.