Re: Why doesn't it use indexes?

On Tue, 2 Jul 2002, Ahti Legonkov wrote:

Check the actual time by explain analyze.
If sequential scan (your table is small e.g.) is faster
then there is no need for index use.
Also check the enable_indexscan variable.

> Hi,
> 
> I have this query:
> select * from reo inner join usr on reo.owner_id=usr.user_id
> 
> I also have created these indexes:
> CREATE INDEX "owner_id_reo_key" ON reo (owner_id);
> CREATE INDEX "user_id_user_key" ON usr (user_id);
> 
> Explain tells me this:
> Merge Join  (cost=1341.74..1481.12 rows=299697 width=461)
>    ->  Sort  (cost=775.05..775.05 rows=6629 width=328)
>          ->  Seq Scan on apartment_reo reo  (cost=0.00..354.29 rows=6629 
> width=328)
>    ->  Sort  (cost=566.69..566.69 rows=4521 width=133)
>          ->  Seq Scan on USER usr  (cost=0.00..292.21 rows=4521 width=133)
> 
> Why it does not use indexes I have created?
> 
> 

-- 
Achilleus Mantzios
S/W Engineer
IT dept
Dynacom Tankers Mngmt
tel:    +30-10-8981112
fax:    +30-10-8981877
email:  achill@matrix.gatewaynet.com       mantzios@softlab.ece.ntua.gr