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(at)matrix(dot)gatewaynet(dot)com
mantzios(at)softlab(dot)ece(dot)ntua(dot)gr