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.